力学进展 2019 , 49 (1): 201910-201910https://doi.org/10.6052/1000-0992-18-007

力学

多物理场耦合作用分析的近场动力学理论与方法

顾鑫 1 ,章青 1 , ,,ErdoganMadenci 2

1河海大学力学与材料学院工程力学系, 南京 211100
2 Department of Aerospace and Mechanical Engineering,University of Arizona,Tucson 85721, USA

Review of peridynamics for multi-physics coupling modeling

GU Xin 1 ,ZHANG Qing 1 , ,,MADENCI Erdogan 2

1 Department of Engineering Mechanics,College of Mechanics and Material,Hohai University, Nanjing 211100, China
2 Department of Aerospace and Mechanical Engineering,University of Arizona, Tucson 85721, USA

中图分类号:O33,O34,O39

文献标识码:A

通讯作者: †E-mail: lxzhangqing@hhu.edu.cn

收稿日期:2018-04-25

接受日期:2018-09-5

网络出版日期:2019-01-15

版权声明:2019 开云棋牌官方 This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

基金资助: 国家自然科学基金项目(11672101,11372099)、国家重点研发计划(2017YFC1502603,2018YFC0406703)、江苏省自然科学基金项目(BK20151493)和2016年国家建设高水平大学公派研究生项目(201606710089)资助.

作者简介:

作者简介:章青, 男, 博士, 河海大学力学与材料学院教授、博士生导师、工程力学国家重点学科学术带头人. 现任国际计算力学协会理事, 开云棋牌官方 理事及计算力学专委会副主任, 南方计算力学联络委员会主任等多个学会的理事和常务理事. 《计算力学学报》《应用数学与力学》《力学季刊》《河海大学学报》 Journal of Peridynamics and Nonlocal Modeling 等期刊编委, 多个国际学术会议主席和学术委员会委员. 长期从事计算固体力学、工程材料的力学特性与本构理论、工程结构灾变破坏力学、多场耦合等问题的研究. 主持和参加国家重点基础研究发展计划、国家科技攻关、国家重点研发计划、国家自然科学基金和重点工程科研项目80余项, 在国内外学术刊物和会议上发表论文200余篇, 出版专著和教材9部.


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摘要

广义来说, 近场动力学(peri-dynamics,PD)是假设每个物质点在承受一定范围内的非接触相互作用下,研究整个物理系统演化过程的理论,为涉及非连续和非局部相互作用的问题提供了一个统一的数学框架,具有广泛的适用性.在简要介绍诸多工程对于多物理场模型和数值计算软件的迫切需求后,针对现有商用软件在处理结构非连续演化问题时遇到的瓶颈,引入近场动力学理论和方法. 概述近场动力学固体力学模型,系统阐述近场动力学扩散模型和近场动力学多物理场耦合建模的研究现状和进展,主要涉及电子元器件、电子封装和岩土工程领域的多物理场耦合建模,包括热--力、湿--热--力、热--氧、热--力--氧、力--电、热--电、力--热--电、多孔介质的水--力流固相互作用等非耦合、半耦合与完全耦合模型,强调发展耦合方程数值解法的重要性.最后对扩散问题和多物理场耦合问题的近场动力学理论模型、数值算法和工程应用做进一步展望.

关键词: 近场动力学 ; 非局部理论 ; 多物理场 ; 耦合建模

Abstract

Generally, peridynamics is a theory focusing on the evolution of a physical system, which is based on the assumption that each material point interacts with the other material points within a certain domain through non-contact or nonlocal interactions. It provides a unified mathematical framework for analyzing problems involving the evolving discontinuities and nonlocality. After a brief introduction of the peridynamic solid models and the urgent requirements on multi-physics models and corresponding commercial software, which have the capability of dealing with the evolving discontinuities, we made a systematic review on peridynamic nonlocal diffusion and peridynamic multi-physics coupled modeling. It can be found that the existing multi-physics coupled modeling studies mostly concentrated on the problems in the electronic components, electronic packaging and geotechnical engineering fields, including the un-coupled, partial coupled and fully coupled models about thermo-mechanics, hygro-thermo-mechanics, thermo-oxidative, thermo-mechanics-oxidative, mechanics-electronics, thermo-electronics, thermo-mechanics-electronics, fluid-solid interaction model for porous medium. Finally, several potential problems in the theoretical model, numerical algorithm and engineering application of peridynamic diffusion modeling and multi-physics coupled modeling are suggested.

Keywords: peridynamics ; nonlocal theory ; multi-physics field ; coupled modeling

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顾鑫 , 章青 , ErdoganMadenci . 多物理场耦合作用分析的近场动力学理论与方法 [J]. 力学进展 , 2019, 49(1): 201910-201910https://doi.org/10.6052/1000-0992-18-007

GU Xin , ZHANG Qing , MADENCI Erdogan . Review of peridynamics for multi-physics coupling modeling [J]. Advances in Mechanics , 2019, 49(1): 201910-201910https://doi.org/10.6052/1000-0992-18-007

1 引 言

传统连续介质力学理论建立在局部相互作用思想的基础上,并以偏微分方程进行问题的刻画与描述,与此相对应的以有限单元法为代表的数值方法在众多科学问题和工程应用领域取得了极大成功.但在处理固体材料和结构破坏等不连续变形时遇到瓶颈,根源在于控制方程中变量的空间导数在裂纹等强不连续处不存在、在材料界面等弱不连续处不唯一(Silling 2000,Silling et al. 2007,Madenci & Oterkus 2014,Bobaru et al. 2016,黄丹等 2010,章青等 2016a,乔丕忠等 2017), 为此,往往需将控制方程和不连续条件分开处理, 造成求解困难. 2000年,美国Sandia国家实验室的 Silling 博士提出近场动力学(peridynamics, PD)理论和相应数值方法,希望在统一的数学框架下模拟固体结构中裂纹萌生、扩展、分叉和汇合的演化过程.

近场动力学的固体力学模型及其数值方法已在不同尺度的各种材料与结构的静动力变形和裂纹扩展问题中得到成功应用(Madenci & Oterkus 2014;Bobaru et al. 2016;黄丹等 2010;章青等 2016b;乔丕忠等 2017;Gu et al. 2016,2017,2018).近场动力学是一种以积分方程为基础的基于非局部相互作用思想的连续介质力学理论,积分型非局部空间导数的定义避免了传统空间导数不存在或不唯一问题,且其通过近场范围内物质点间的非接触相互作用建模、传递物理量与考虑材料和结构的特征长度尺度.当近场范围尺寸趋于零时, 该理论解答收敛于传统局部理论解答,是对传统连续介质力学理论的一种有益补充.近场动力学理论分为键型近场动力学(bond-based PD, BB PD)、常规状态型近场动力学(ordinary state-based PD, OSB PD)和非常规状态型近场动力学(non-ordinary state-based PD, NOSB PD).广义来说,近场动力学是假设每个物质点在承受一定范围内的非接触相互作用下,研究整个物理系统变化过程的理论(韩非 2017),为涉及非连续和非局部相互作用的问题提供了一个统一的数学模型,已被推广至热质传导/扩散领域和多物理场耦合领域,以充分利用其便于处理结构非连续变形问题和包含非局部相互作用效应的特点.

实际工程结构都处在力、水(水分、蒸汽、渗流)、热、电、磁等多物理场环境中,涉及不同的多场耦合建模, 如:微机电系统涉及力--热、力--电、电--热、力--电--热、力--热--电--磁、湿--热--力等多场耦合,环境地质与岩石力学问题涉及热--水--力耦合、热--水--力--化耦合,高寒地区饱和冻土和混凝土结构、高温干旱和潮湿地区的混凝土结构开裂破坏均涉及水(湿)--热--力耦合,页岩气等油藏开采与大坝的高水压水力劈裂问题与多孔弹性介质的水--力流固耦合问题密切相关.随着研究的不断深入,各工程领域对多物理场耦合模型和仿真软件的需求大、精度和稳健性要求高(孙培德等2007), 虽然已有COMSOL, ANSYS,ADINA等当前广泛采用的多物理场计算平台,但在涉及结构破坏等不连续问题时尚有不足(徐涛和宋力 2007).发展基于近场动力学的多物理场耦合模型、数值计算方法和计算软件将为多场耦合问题的研究开辟新的途径.

近场动力学固体力学模型和热质传导/扩散模型是基于近场动力学方法建立多物理场耦合模型的基础.在简要介绍近场动力学固体力学模型的基础上,本文将系统总结近场动力学扩散模型和多物理场耦合模型的研究进展,包括热--力、湿--热--力、热--氧、热--力--氧、力--电、热--电、力--热--电、多孔介质的水--力流固相互作用等非耦合、半耦合、完全耦合模型,并对基于近场动力学方法的多物理场耦合模型、数值算法和工程应用进行展望.

2 近场动力学固体力学模型

图1(a)所示, 在传统连续介质力学线弹性理论中,代表体积单元与邻近接触的其他代表体积单元相互作用,其控制方程、应变能密度和本构关系分别为

$$\rho {\ddot{\pmb u}} (\pmb x,t) = \nabla \cdot \pmb \sigma + \pmb b (\pmb x,t)(1)$$

$$W^l = \frac{1}{2}\pmb \varepsilon :\pmb D :\pmb \varepsilon(2)$$

$$\pmb \sigma = \pmb D :\pmb \varepsilon(3)$$

图 1 传统局部接触模型和近场动力学非局部长程作用模型. (a)传统局部接触模型, (b)近场动力学非局部长程作用模型

其中, $\nabla $为散度算子, $\pmb \sigma$为Cauchy应力张量, $\pmb b $为体力密度, $\rho $为质量密度, $\pmb u$为物质点位移, ${\ddot{\pmb u}}$为加速度, $W^l$为应变能密度,$\pmb D $为描述材料性质的四阶张量, $\pmb \varepsilon $为应变张量.不难看出:应力--应变本构模型、应变能密度和控制方程都是位移梯度的函数,计算涉及位移的空间导数,导致传统连续介质力学在处理断裂破坏等非连续问题时存在困难.

图1(b)所示, 在近场动力学理论中,物质点受其近场范围内所有其他物质点的共同作用,以非局部作用积分项取代传统连续介质力学模型中的散度算子项,则其控制方程、应变能密度和本构力函数分别为(Silling 2000,Silling et al. 2007)

$$\rho {\ddot{\pmb u}} (\pmb x,t) = \int_{H_x} \pmb f (\pmb x,\pmb x' ,\pmb u ,\pmb u' ,t) {\rm d}V_{x'} + \pmb b (\pmb x,t)(4)$$

$$W^{nl} = \frac{1}{2}\int_{H_x} w(\pmb \eta ,\pmb \xi ){\rm d}V_{x'} = \frac{1}{2}\int_{H_x} \int_0^\eta \pmb f (\pmb x,\pmb x' ,\pmb u ,\pmb u' ,t) \cdot {\rm d}\pmb\eta {\rm d}V_{x'}(5)$$

$$\pmb f = \underline{\pmb T}\left[ {\pmb x,t} \right]\left\langle {\pmb x' - \pmb x} \right\rangle - \underline{\pmb T }\left[ {\pmb x' ,t} \right]\left\langle {\pmb x - \pmb x' } \right\rangle(6)$$

其中, $\pmb f$为本构力函数, 表示$t$时刻$\pmb x' $处单位体积物质点施加于$\pmb x$处物质点的作用力密度; $ \int_{H_ x } \pmb f (\pmb x,\pmb x',\pmb u ,\pmb u' ,t){\rm d}V_ {x' } $为物质点的合内力矢量, ${\rm d}V_{x' } $是$\pmb x' $处物质点的体积微元, $\delta$为近场范围尺寸, $H_x = H(\pmb x,\delta ): = \left\{ {\pmb x' \in R:\left\{ {\left\| {\pmb x' - \pmb x} \right\| \leq \delta }\right\}} \right\}$为物质点$\pmb x$的作用范围内物质点$\pmb x'$的集合, 近场范围外物质点与物质点$\pmb x$间相互作用力$\pmb f = {\rm 0}$. $W^{nl}$为近场动力学应变能密度, $\pmb\xi = \pmb x'- \pmb x$为初始相对位置矢量, $\pmb\eta = \pmb u'- \pmb u$为现时相对位移矢量; $w(\pmb \eta ,\pmb\xi)$为发生相对位移$\pmb\eta $时, 物质点对存储的单位体积应变能密度.$\underline{\pmb T }$是力矢量状态,是一个描述材料本构关系的力密度矢量, 为PD本构建模的关键; $\left[\ \right]$中表示该状态所属的空间和时间点, $\left\langle \ \right\rangle $表示该状态作用或映射的对象. 需要指出的是:本构力函数或者力状态都是位移差值的函数,可有效避免导数计算引起的奇异性问题.

以三维弹性材料模型为例,键型、常规状态型和非常规状态型近场动力学固体力学模型,力矢量状态(或本构力函数)分别为(Silling 2000,Silling & Askari 2005,Silling et al. 2007)

$$ \left. \begin{array}{ll} \underline{\pmb T }\left[ {\pmb x,t} \right] = - \underline{\pmb T }\left[ {\pmb x' ,t} \right] = \frac{1}{2}\pmb f ,\pmb f ( \pmb \xi ,\pmb \eta ) = cs\frac{\pmb \xi +\pmb \eta }{\left| \pmb \xi + \pmb \eta \right|},&\quad \mbox{BB-PD} \\ \underline{\pmb T }\left[ {\pmb x,t} \right] = \left( \frac{3k\theta }{m}\omega \left| \pmb\xi \right| + \alpha \omega \underline{e}^d \right)\frac{\pmb \xi + \pmb \eta }{\left| \pmb \xi + \pmb \eta \right|},\quad k = K,\quad \alpha = \frac{15G}{m},&\quad \mbox{OSB-PD} \\ \underline{\pmb T }\left[ {\pmb x,t} \right] = \omega \pmb P\pmb K^{ - 1}\pmb\xi ,&\quad \mbox{NOSB-PD} \\ \end{array} \right\}(7)$$

式中, $c$为微观模量, $s$为物质点对伸长率; $\omega$为影响函数, 加权量$m = \omega \left| \pmb\xi \right|\cdot \left|\pmb\xi \right| = \int_{H_x } \omega \left| \pmb\xi \right|^2{\rm d}V_{x'}$, 体应变$\theta = \frac{3}{m}\left[ {\omega \left| \pmb\xi \right|\cdot (\left| {\pmb\xi + \pmb\eta } \right| - \left| \pmb\xi \right|)} \right]$, 拉伸标量偏量部分$\underline{e}^d = \left(\left| {\pmb\xi + \pmb\eta } \right|-\right.$\linebreak $\left. \left| \pmb\xi \right|\right) - \frac{\theta \left| \pmb\xi \right|}{3}$, $K$和$G$分别为体积模量和剪切模量; $\pmb P $是第一Piola-Kirchhoff应力, $\pmb K =$\linebreak $ \int_{H_x } \omega \left( {\pmb\xi \otimes \pmb\xi } \right){\rm d}V_{x' } $为形状张量.

需要指出的是: 在特定的物理场中,两物质点间的相互作用通过本构函数或响应函数描述,该函数与物质点空间相对位置相关.如果该响应函数只与近场范围内单一物质点对相关,则称为键型近场动力学模型;如果该响应函数与两个物质点所处的空间状态有关(即两物质点各自受其近场范围内的其他物质点作用),则称为状态型近场动力学模型.

3 近场动力学扩散模型研究进展

3.1 扩散问题的近场动力学描述

传热传质、非局部扩散和反常扩散问题具有非局部效应,研究者开展了基于近场动力学方法的扩散模型或传热传质研究.采用偏微分方程描述的热传导、水分浓度扩散、渗流水分含量扩散和电传导问题的传统局部扩散方程分别为(Jabakhanji 2013,Oterkus 2015)

$$\rho c_v \frac{\partial T\left( {\pmb x,t} \right)}{\partial t} = k_{\rm T} \nabla ^2T + s_{\rm T} \left( {\pmb x,t} \right) = - \nabla \cdot \pmb q _{\rm T} + s_{\rm T} \left( {\pmb x,t} \right),\quad \pmb q _{\rm T} = - k_{\rm T} \nabla T(8)$$ $$\frac{\partial C_{\rm M} \left( {\pmb x,t} \right)}{\partial t} = D_{\rm M} \nabla ^2C_{\rm M} + s_{\rm M} \left( {\pmb x,t} \right)(9)$$

$$\frac{\partial \theta \left( {\pmb x,t} \right)}{\partial t} = - \nabla \cdot \left[ {k_{h_{\rm m} } \nabla \left( {h_{\rm m} + z} \right)} \right] + s_{h_{\rm m} } \left( {\pmb x,t} \right) = - \nabla \cdot \pmb q _{h_{\rm m} } + s_{h_{\rm m} } \left( {\pmb x,t} \right),\pmb q _{h_{\rm m} } = - k_{h_{\rm m} } \nabla \left( {h_{\rm m} + z} \right)(10)$$

$$c_{\rm E} \frac{\partial \varPhi \left( {\pmb x,t} \right)}{\partial t} = k_{\rm E} \nabla ^2\varPhi + s_{\rm E} \left( {\pmb x,t} \right) = - \nabla \cdot \pmb j + s_{\rm E} \left( {\pmb x,t} \right),\pmb j = - k_{\rm E} \nabla \varPhi(11)$$

其中, $\nabla ^2 = \partial _{xx}^2 + \partial _{yy}^2 + \partial _{zz}^2 $为拉普拉斯算子, $\nabla = \left( {\frac{\partial }{\partial x},\frac{\partial }{\partial y},\frac{\partial }{\partial z}} \right)$为梯度算子, $\nabla \cdot $为散度算子, $T$为温度, $c_v $为材料比热容, $k_{\rm T}$为材料热传导系数, $s_{\rm T} $为外部单位体积生热量, $\pmb q _{\rm T} $为热流密度或热通量. $C_{\rm M} $为水分浓度, $D_{\rm M}$为(湿分)水分扩散系数, $s_{\rm T} $为外溢或吸收导致的水分浓度改变.$\theta $为体积含水量, $h_{\rm m} $为介质水头, $z$为高程水头, $H = h_{\rm m} + z$为总水头, $k_{h_{\rm m} } $为介质导水率, $s_{h_{\rm m} } $为外溢或吸收水分, $\pmb q _{h_{\rm m} } $为水流通量矢量.$c_{\rm E} $为电容, $\varPhi $为电势, $k_{\rm E} $为材料电导率,$s_{\rm E} $为外源项, $\pmb j $为电流密度或电流通量.

采用近场动力学方法对上述四类问题进行建模,相对应的键型近场动力学扩散方程分别为(Jabakhanji 2013,Oterkus 2015)

$$\rho c_v \frac{\partial T\left( {\pmb x,t} \right)}{\partial t} = \int_{H_ x } f_{\rm T} \left( T,{T}',\pmb x,\pmb x' ,t \right){\rm d} V_{x' } + s_{\rm T} \left( {\pmb x,t} \right)(12)$$ $$\frac{\partial C_{\rm M} \left( {\pmb x,t} \right)}{\partial t} = \int_{H_ x } f_{\rm M} \left( {C_{\rm M} ,{C}'_{\rm M} ,\pmb x,\pmb x' ,t} \right){\rm d}V_{x' } + s_{\rm M} \left( {\pmb x,t} \right)(13)$$

$$ \frac{\partial \theta \left( {\pmb x,t} \right)}{\partial t} = \int_{H_ x } f_{h_{\rm m} } \left( {h_{\rm m} ,{h}'_{\rm m} ,\pmb x,\pmb x' ,t} \right){\rm d}V_{x' } + s_{h_{\rm m} } \left( {\pmb x,t} \right)(14)$$

$$c_{\rm E} \frac{\partial \varPhi \left( {\pmb x,t} \right)}{\partial t} = \int_{H_ x } f_{\rm E} \left( {\varPhi ,{\varPhi }',\pmb x,\pmb x' ,t} \right){\rm d}V_{x' } + s_{\rm E} \left( {\pmb x,t} \right)(15)$$

其中, 当近场范围为完整对称线段、圆形或球形时,不同物理场扩散问题的响应函数及其相应的一维、二维和三维PD微观传导/扩散系数分别如表1,所示.

表1 不同物理场传导/扩散问题的PD响应函数( Oterkus 2015 )

注:A为一维杆件横截面面积,^为二维板厚度.

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此外, 响应函数还可以取为$f_{\rm T} = \kappa _{\rm T} \frac{{T}' - T}{\left| \pmb\xi \right|^2}$和$f_{\rm T} = \kappa _{\rm T} \left( {{T}' - T} \right)$等形式, 此时微观传导系数发生变化(Agwai 2011). 上述四式中响应函数可写为

$$f_{\rm T} = {Q}_{\rm T} \left[ {\pmb x,t} \right]\left\langle {\pmb x' - \pmb x} \right\rangle - {Q}_{\rm T} \left[ {\pmb x' ,t} \right]\left\langle {\pmb x - \pmb x' } \right\rangle(16)$$

下标T可分别替换为M, $h_{\rm m} $和E,为状态型近场动力学中的标量热/水/电流量密度状态. 需要指出:由于采用相同近场范围内的积分表达,近场动力学运动方程和扩散方程可以统一在一个非局部微分算子(Du et al.2012,2013, Xu et al. 2016)框架内.

3.2 基于近场动力学方法的扩散问题研究成果

为弥补传统局部理论在分析微电子器件涉及的不连续力学问题时的不足,Gerstle 等 (2008)Read 等(2011)首次给出热传导、电传导、以及原子和空穴扩散的键型近场动力学非局部扩散模型,提出了温度场、电场、原子空穴浓度场变化的PD表述和数值求解方法,研究了一维电子迁移的多物理耦合过程,得到了机械变形、热传导、电势分布(电荷流动)和原子空穴扩散的结果,为扩散问题和多物理场耦合问题的PD建模研究奠定了基础. 此后,Oterkus等 (2013)将电迁移问题的近场动力学分析方法拓展至高维,研究了由电迁移、热迁移和应力迁移诱发原子空穴扩散而导致微结构材料性质裂化问题.Bobaru和Duangpanya (2010,2012)从热传导Fourier定律和能量守恒法则出发构建了键型PD一维、二维非稳态热传导方程,基于线性变化势场分布和局部与非局部等效方法、详细给出两种微观热传导函数的推导方法,通过典型一维、二维热传导问题验证了PD解答,并研究了考虑含裂纹方板的热传导问题.Agwai等(2011)通过典型一维热传导问题验证了该键型PD热传导模型的合理性.此后,Agwai (2011)Oterkus等(2014a)采用Euler-Lagrange方程和热能守恒方法推导了状态型近场动力学热传导方程,初步给出了非常规态型热传导模型,简化后得到键型近场动力学热传导方程,提出了3种热响应(内核)函数形式以及对应的微观热传导系数的计算方法,给出详细的空间离散积分、时间差分、初始条件和边界条件施加的数值实现方法,验证了键型PD模型在分析一维杆、二维板和三维块体在多种边界条件下热传导问题的有效性.Chen 和Bobaru (2015a)以及Jafari 等(2017)分别研究了带有不同热响应(内核)函数键型PD热传导模型解答的$\delta $ 收敛性和$m$收敛性问题.刘硕等(2018)采用键型近场动力学无网格粒子法与有限元耦合方法研究了二维热传导问题.王飞 等(2017)给出了非均匀材料的键型PD热传导方程,通过键两端物质点热传导参数的加权平均描述非均匀特征,并分析PD各个计算参数对热传导结果的影响;刘英凯和程站起(2018)研究了功能梯度材料的热传导问题.Liao 等(2017)采用非常规状态近场动力学的缩减算子定义了非局部积分型温度梯度,构建了非常规状态近场动力学热传导模型.Wang L J等 (2016,2018)研究了上述Fourier型热传导的键型PD模型的Green函数解答,并进一步提出了非Fourier型热传导的PD模型,给出了广义态型热传导方程和键型热传导方程,并对比传统非Fourier结果和实验结果, 验证了该键型PD模型的有效性.王超聪等(2017)建立基于接触近邻的近场动力学热传导模型,引入热烧蚀断键准则, 模拟了热防护材料的热烧蚀温度场演化.

Han 等(2016)Diyaroglu 等 (2017a,2017b)给出多种物理场的键型近场动力学扩散方程形式,通过LINK33三维热传导杆单元和MASS71热质量单元,在ANSYS软件中分别实现了PD热扩散、水分浓度扩散、电传导、归一化湿度场扩散问题的数值模拟,以充分利用ANSYS软件的高效隐式求解器,得到的一维杆和三维交叉堆叠封装结构浓度扩散问题的PD预测结果具有很高的精度.

此外, 考虑``均质单管''水分运输通道,Jabakhanji和Mohtar (2015)建立了适用于饱和、均质和各向同性或各向异性土壤介质(多孔介质)中水分流动的键型近场动力学扩散模型,包括水分流动的扩散方程和湿度通量表达,给出由传统水分流动模型确定一维、二维PD微观水力传导系数的方法.进而针对非均匀或非饱和土体不具有常量水力传导系数的特点,考虑``并行双管''水分运输通道,将该模型推广到非饱和与非均质土壤介质,对比验证了一维均匀饱和土柱的排水问题、二维水平土层中的水分扩散问题以及初始饱和含水量的二维垂直非均质土柱排水问题.同一阶段,Katiyar 等(2014)提出了多孔介质的压力驱动流体输运问题或渗流问题的PD方法,基于质量守恒方程的变分原理, 推导出状态型近场动力学传质方程,考虑多孔介质的物质点间存在的流动通道,建立单相牛顿流体(小常压缩系数液体)在非均质各向异性多孔介质中的二维渗流模型,并给出了均质各向同性多孔介质的键型PD渗流模型,采用该PD渗流模型模拟了均质和非均质方形区域的五点井汇流问题. 此外,Delgoshaie 等 (2015)Meyer 和 Jenny(2017)从离散孔隙网络结点的流量守恒出发,将多孔介质均匀化为连续介质, 建立积分型非局部达西定律, 归一化后,在空间均匀对称下, 能复现非局部扩散模型方程(Du et al. 2012),与局部连续达西定律相比,非局部连续达西定律得到的结果更接近孔隙网络流动模型的计算结果.

4 近场动力学多物理场耦合模型研究进展

4.1 考虑多物理场作用效应的非耦合PD本构模型

在近场动力学中, 本构力函数或力矢量状态的构造是建模关键, 在单纯力场中,通常依赖于近场范围内物质点间初始和现时相对位置.分布规律已知的温度场、水分或离子浓度场、多孔介质渗流场等对固体结构变形场的影响可以反映在本构力函数或力矢量状态中,类似于传统热弹性本构建模, 但不能考虑扩散效应对温度、湿度和结构响应等的影响,是一种单向非耦合的多物理场作用下的近场动力学模型.

为研究热力载荷作用下的电子封装结构的力学响应,Kilic 和 Madenci(2010)首次提出了含温度项的键型PD热力本构函数,采用该非耦合PD热力模型分析了给定温度变化下物体的变形规律,研究了含初始裂纹的淬火玻璃在不同初始缺陷和温度条件下的裂纹扩展问题,捕捉到了裂纹偏转、分叉及连接现象(Kilic & Madenci 2009), 如图2所示. 此后,Jeon 等 (2015)Mella 和 Wenman (2015)Xu等(2018)以及Giannakeas 等(2017)分别采用非耦合键型PD热力模型研究了钢化玻璃、核燃料芯块、淬火玻璃板、陶瓷板块在常规热力载荷、冷水浴或热冲击载荷作用下的动态裂纹扩展.基于同样的建模思路,Madenci 和 Oterkus (2017a)Zhang 和 Qiao(2018)在力矢量状态(Silling et al. 2007,Le et al.2014)中加入物质点的温度改变(变温)项,分别建立了非耦合的常规状态型近场动力学热弹性模型和热黏弹性模型,分析了热力载荷下矩形板变形与双材料梁(如图3)的变形开裂问题.Oterkus等(2014c)在键型PD本构力函数中考虑湿度增量、蒸汽压或水压的影响,建立了非耦合PD湿热力本构模型.苏伯阳等(2018)将该湿热力模型应用到非均匀复合材料中,模拟了不同湿热环境下复合材料的冲击损伤问题.

图 2 淬火玻璃裂纹扩展、偏转、分叉及连接现象( Kilic & Madenci 2009 )

图 3 均匀温升导致双材料梁界面裂纹扩展 ( Zhang & Qiao 2018 )

考虑温度(Kilic & Madenci 2009,2010)、湿度 (Oterkus et al.2014c)、蒸气压(Oterkus et al. 2014c)或水压(Oterkus et al.2017)对固体变形的影响, 键型PD本构力函数可构造为

$$ \pmb f (\pmb \xi ,\pmb\eta ,T,C,P) = c\left( {s - \alpha T_{\rm avg} - \beta C_{\rm avg} - \gamma P_{\rm avg} }\right)\frac{\pmb \xi + \pmb \eta }{\left| {\pmb \xi +\pmb \eta } \right|}(17)$$

其中, $s$为键伸长率, $T_{\rm avg} $和$C_{\rm avg}$为物质点对的自身与环境温度或湿度差值的平均, 即$T_{\rm avg} {\rm = }\frac{ {T - T_0 } + {{T}' - T_0 } }{2}$和$C_{\rm avg} = \frac{{C - C_0 } + {{C}' - C_0 } }{2}$, $T_0 $和$C_0$为环境温度和湿度, $P_{\rm avg} {\rm = }\frac{P + {P}'}{2}$为键两端物质点的平均压力, $c = \frac{18K}{\pi \delta^4}$为三维微观模量, $K$为体积模量, $\alpha $为材料热膨胀系数,$\beta $为材料吸湿膨胀系数, $\gamma $为孔压系数(Oterkus et al.2014c,2017).

4.2 考虑多物理场作用效应的PD耦合模型

基于非局部PD固体力学模型和PD扩散模型,研究者开展了PD多物理场耦合模型研究,主要针对电子器件、电子封装结构和土壤岩石等多孔介质,涉及热--力耦合、热--氧耦合、热--力--氧耦合、湿--热--力耦合、力--电耦合、热--电耦合、力--热--电耦合和水--力流固耦合等多物理场作用效应.

4.2.1 热--力耦合模型

在完全耦合的PD热力模型中,温度场对变形场的影响通过热力本构模型反映在固体力学方程中,而变形场对温度场的影响则通过结构变形加热和冷却项反映在热传导方程中.Agwai (2011)Oterkus 和 Madenci (2013)Oterkus等(2014b)基于热能和机械能能量守恒方程和热力学自由能函数(Silling & Lehoucq 2010), 建立了完全耦合的状态型近场动力学热力模型,并简化得到键型PD热力耦合模型与无量纲化的键型PD热力耦合模型,他们采用交错差分格式求解耦合方程,分析验证了一维、二维、三维热传导问题,研究了一维杆件、二维均质板和单向纤维增强复合薄板的热力耦合变形问题.基于该键型PD完全耦合热力模型,Chen等(2016,2017)忽略热传导方程中的变形影响项,建立了空间均匀和非均匀离散模型的单向弱耦合键型PD热力模型,在模型中, 温度场变化对结构变形产生影响,但变形场不对温度场的改变产生影响,采用Newton-Raphson方法在MOOSE软件实现其隐式计算,分析了二维和三维核燃料芯块的断裂问题.Hu 等(2018)建立了基于非规则非均匀离散的键型和常规态型近场动力学固体力学模型和热传导模型,验证了非均匀离散PD模型在分析结构变形和热传导问题的有效性,最后采用隐显式方法分析了三维核燃料芯块的断裂问题,其结果如图4,所示.D'Antuono 和 Morandini(2017)采用常规状态型近场动力学热力本构方程描述结构变形,以键型PD热传导方程描述温度场变化, 发展了弱耦合PD热力模型,采用多速率显式积分技术求解两类控制方程,在Peridigm中模拟了弹脆性陶瓷薄板与厚板的热冲击致裂行为,观察到二维有序平行裂纹集和三维柱状节理蜂窝裂纹模式.Wang Y T等(2018)采用键型PD热力耦合模型分析了岩石热力裂纹问题.Oterkus(2015)系统研究了多物理场耦合问题,除上述热扩散和完全耦合热力模型外,还涉及电子封装领域湿热蒸汽变形的湿--热--力耦合问题(Oterkus et al.2014c)和电子迁移致损问题(Oterkus et al.2013)、高温环境下聚合物基复合材料表面氧化或老化的热--氧耦合问题(Madenci & Oterkus 2017b),以及核燃料芯块高温开裂的热--力氧耦合问题(Oterkus & Madenci2017).

图 4 热载荷作用下核燃料芯块开裂后的温度、位移和损伤分布 ( Hu et al. 2018 ). (a)温度(K), (b)径向位移(mm), (c) 损伤

4.2.2 力--电、热--电、热--力--电耦合模型

针对柔性电子器件领域的多物理作用,Roy 和 Roy(2016)提出了力--电(挠曲电)耦合的近场动力学模型,该模型能够描述纳米尺度挠曲电耦合导致的对称电介质非均匀变形问题.基于纳米尺度的电子跃迁将会引起材料的压电电阻效应,且电流具有非局部性,Prakash 和 Seidel (2016,2017)考虑变形对电子跃迁和电势分布影响的单向作用效应,建立了键型近场动力学力电耦合模型, 通过改变导电系数和压阻系数,分析了碳纳米管(CNT)增强聚合物纳米复合材料的压电电阻响应问题,得到的结果如图5,所示.基于Seebeck效应、Peltier效应、Thomson效应和高斯定理,张振宇(2015)提出适用于含不连续缺陷热电材料的基于接触近邻Voronoi胞元的近场动力学热电耦合模型,并分析了三维热电器件的热电转换效率问题.Assefa 等 (2017a,2017b)采用广义Fourier热传导定律和广义欧姆定律, 考虑热电耦合效应,基于热能守恒和电荷守恒, 建立了状态型近场动力学热传导和电传导方程,并建立相互耦合的键型PD热电方程,得到了一二维热电耦合问题的键型PD热电模拟结果.Wildman 和 Gazonas(2015,2017)采用近场动力学方法研究了固体电介质在电热力耦合作用下的脆性失效破坏问题,在他们的研究中, 忽略热扩散效应,仅在PD本构模型中考虑由电流焦耳热效应导致的温度改变,将洛伦兹力和开尔文极化力等静电力加到PD本构力中,以反映静电场对机械变形场的影响,电传导系数是温度和电场的非线性函数, 结构变形损伤将改变介电常数,并采用有限差分法或有限元法求解静电场方程,采用无网格粒子法求解近场动力学固体力学方程,介电材料方板在高电压下裂纹扩展模式与实验观测到的脆性固体通道状和树状的介电击穿失效现象吻合良好.

图 5 在0.15%和0.3%拉伸应变水平下,含纯环氧树脂粘合剂微结构损伤和电导率云图( Prakash & Seidel 2017 )

4.2.3 多孔弹性介质中的流--固耦合模型

鉴于传统多孔介质弹性理论不能很好地模拟土壤干缩致裂、油藏开采中水力劈裂等不连续变形问题,研究者发展了近场动力学框架内的多孔介质弹性理论,以描述多孔介质中液体流动与多孔介质固体变形的相互作用.

Turner (2013)在常规状态型近场动力学弹性本构建模时,在力矢量状态中考虑流体孔隙压力效应,建立PD多孔弹性理论的固体变形分析方法,以反映流体压力对多孔介质变形的影响,并分析了地层中液体采掘导致的表面沉降和饱和岩土体固结问题,但该模型通过解析解或者其他数值方法预先给定孔隙压力,不考虑固体变形对液体流动和孔隙压力变化的影响,因而属于非耦合的流固相互作用分析模型.Jabakhanji(2013)基于PD方法分析土壤干缩致裂问题,采用土壤收缩特征曲线(含水量减少导致土壤体积改变)计及水分流动对固体变形和开裂的影响,并与土约束实验的干缩开裂结果进行比较,但该模型只能分析含水率减少导致土壤体积改变引起的土壤收缩致裂问题,且也仅是包含含水量对固体变形作用效应的单向耦合模型. 基于Katiyar 等(2014)提出的多孔介质渗流模型和常规状态近场动力学固体力学模型,Ouchi 等 (2015a,2015b,2016,2017a,2017b)将孔压修正到常规状态型PD弹性模型中,以反映流体运动对固体变形的作用,将多孔介质孔隙率设为介质应变、孔压和总平均应力的函数,以反映固体变形对流体运动的影响,发展了适用于流体驱动断裂问题的非均质多孔弹性介质的流--固耦合模型,通过一维饱和岩体的固结理论结果对该流--固耦合模型进行了验证.进而采用含裂隙渗透系数和孔隙度的孔隙流动方程描述裂隙区域流体运动(裂隙渗透系数和孔隙度分别依赖于裂缝宽度和损伤情况),同时考虑裂隙流体和孔隙流体的对流输运,通过非常规状态PD的力矢量状态施加初始地应力场,分析了平面应变条件下单相流驱动单裂纹扩展问题,研究了水力裂缝与单/多自然裂缝的相互作用(如图6),模拟了天然裂隙储层中多水力裂纹扩展问题,探讨了微观小尺度非均匀性对岩体水力裂纹扩展模式的影响,以及储层非均质特性对垂直水力裂纹偏转、弯曲和分叉的影响.Nadimi 等(2016)采用PDLAMMPS软件带有的近场动力学常规状态黏弹性模型,分析了不同注水速率下的三维非均质地层材料块体的水力劈裂问题.Edmiston (2015)联合运用损伤依赖的局部渗流方程和键型近场动力学方程,提出流体流动与固体变形的双向耦合分析方法以分析水力劈裂问题,该耦合模型通过形函数插值类数值方法计算裂隙压力、并通过体力密度项施加到近场动力学运动方程中,通过变渗透系数反映变形和损伤对局部渗流方程的影响,但未考虑结构变形对渗流方程孔隙率的影响,也没有考虑孔压变化对结构变形的影响.Oterkus等(2017)建立双向流固耦合的近场动力学多孔弹性模型,该耦合模型在键型PD运动方程中引入流体孔压项,通过建立非局部形式的达西渗流方程, 以反映固体变形对孔压变化的影响,分析验证了经典的五点井汇流问题、一二维固结问题和水力压裂裂纹扩展问题,但同样没有考虑结构变形对孔隙率变化的影响.吴凡等(2017)采用键型近场动力学模型,通过追踪裂纹面施加水压力函数载荷方法,初步模拟了射孔水平井剖面的水力压裂问题. 此外,Ishimoto 等(2017)采用无网格粒子近场动力学数值方法与欧拉有限元法耦合建模方法,模拟了压力容器壁裂纹扩展时的氢气泄露问题.

图 6 不含自然裂隙与含自然裂隙储层中多水力裂纹扩展.(a)计算模型, (b) 8500\,s时的损伤分布( Ouchi et al. 2015b )

4.2.4 力--化学腐蚀损伤模型

腐蚀环境中金属表面易发生点蚀现象, 致使材料和结构发生腐蚀损伤开裂,点蚀过程可视为金属离子在固/液双相材料中的溶解扩散问题.基于近场动力学非局部扩散方程, 研究者进行了金属电化学腐蚀破坏分析.Chen 和 Bobaru (2015b)基于PD扩散方程和波动方程开展点蚀损伤研究,采用近场动力学方法描述腐蚀过程中阳极反应的浓度变化过程与相边界移动,建立基于浓度与近场动力学``力键''损伤关系的腐蚀损伤模型,分别进行了一维、二维和三维的点蚀过程分析,得到了图7所示的损伤演化过程,与实验观察到的表面损伤现象具有一致性,证明该PD腐蚀模型能够模拟一定厚度范围内金属腐蚀对结构损伤的影响.Chen等(2016)同时考虑点蚀由活化和扩散控制的机理,研究表面钝化膜对结构点蚀损伤过程的影响.Jafarzadeh 等(2017)在前述近场动力学腐蚀模型基础上,进一步引入再钝化膜和盐膜形成模型.白小敏等(2017)实现了近场动力学对不同过电位下一维点蚀的动力学模拟.De Meo 和 Oterkus(2017)在商业有限元软件ANSYS中建立了近场动力学点蚀损伤模型,利用商业软件中隐式求解算法高效地模拟了二维点蚀损伤开裂问题.De Meo等(2016)采用近场动力学方法,计算模拟了水溶液中含预制裂纹薄铁板的吸附氢应力腐蚀开裂问题,裂纹扩展速度和分叉行为与实验结果吻合良好.

图 7 三维结构点蚀问题的损伤演化(取对称半结构显示) ( Chen & Bobaru 2015b ).(a) $t=0$s, (b) $t=5$s, (c) $t=10$s, (d) $t=20$s

4.2.5 水分/离子浓度--力耦合模型

由于湿热应力和蒸气压的存在,电子封装结构在制造过程中吸收的水分易使结构产生变形与损伤,Oterkus等(2014c)建立了湿--热--力耦合模型,在已知热量温度场和水分湿度场条件下,构造包含变形、温度、湿度和蒸气压的键型PD本构力函数,给出键型PD热传导模型、水分浓度扩散模型与蒸气压的计算方法,分别验证了热--力模型和水(湿)--力模型的预测结果,以及电子封装结构在湿热蒸汽变形条件共同作用下的位移场结果. 最近,Wang H等 (2018a)采用近场动力学研究了锂电池断裂问题,采用近场动力学微分算子将裂尖局部形式的锂离子浓度方程转化为对应的非局部积分形式,同时在键型PD本构力函数中加入锂离子浓度的影响,初步计算模拟了含多裂纹电极板的开裂.

4.3 耦合模型的数值解法

采用显式动力学方法求解PD积分方程时,空间域常采用均匀无网格粒子离散, 且每一物质点所属变量为常数,空间积分采用中心单高斯点积分法,时间域采用向前差分、中心差分或四阶龙格库塔差分等格式,以使得计算结果的稳定性、收敛性和精度得到保证 (Silling & Askari 2005). 通常来说, 多物理场模型的控制方程是相互耦联的,常用的解法包括: (1)分离交错式解法: 将所有控制方程分开考虑,按时间序列交错迭代求解, 直到计算结果满足收敛条件(Oterkus et al.2014b,戴旭东等 2001),发展合适的无条件稳定交错算法能较为高效稳定的求解耦合方程(Farhat et al. 1991);(2)整体解法: 将所有控制方程作为一个系统,采用隐式方法整体求解方程变量(Oterkus et al. 2014b);(3)通过提供方程变量间的函数关系, 将不同场方程解耦成非耦联的,分别求解各自场的独立积分方程.

目前, PD多物理场研究大多采用分离交错式解法,但不同控制方程显式时间积分的稳定时间步长可能存在较大的量级差距,交错计算方式极大的增加了计算时间, 无条件稳定的隐式时间积分方法将具有优势.此外, 常采用的基于空间均匀离散的PD计算格式,欲获得高精度结果通常需要匹配较精细的离散网格, 从而导致计算量巨大问题,因此有必要发展基于非均匀离散的PD计算格式, 以及基于GPU等的并行计算方法.

5 结语

经过近20年的发展,近场动力学已形成了较为完善的理论体系和数值计算方法.因近场动力学自然包含非局部效应和便于处理结构非连续演化的特点,自问世以来, 就备受数学、力学、物理和工程界的关注,在宏、细、微观各个尺度的诸多材料和结构的静动力变形和非连续力学问题中得到广泛应用,并在多物理场问题的研究中得到初步拓展.

本文简要介绍了近场动力学固体力学模型,系统综述了近场动力学扩散模型和近场动力学多物理场耦合建模的研究现状和进展,现有研究主要集中在电子元器件、电子封装结构和岩土工程领域.扩散和多物理场问题的近场动力学理论和数值计算方法虽然取得了众多成果,但仍有诸多问题有待进一步研究解决, 如:多物理场的状态型PD扩散模型和耦合模型的构建、键型和态型PD非线性材料的本构力函数的建立、非常规态型PD的稳定性问题和裂纹扩展模拟问题、非均匀离散与自适应分析、PD耦合方程的高效稳定求解方法、多物理场作用下多尺度问题的PD模拟、各种增强复合材料的多物理场模型和应用分析等.

致 谢

The authors have declared that no competing interests exist.


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. Chinese Journal of Theoretical and Applied Mechanics, 50 : 339 - 348 ).

DOIURL[本文引用: 1]摘要

求解含裂纹等不连续问题一直是计算力学的重点研究课题之一,以偏微分方程为基础的连续介质力学方法处理不连续问题时面临很大的困难. 近场动力学方法是一种基于积分方程的非局部理论,在处理不连续问题时有很大的优越性. 本文提出了求解含裂纹热传导问题的一种新的近场动力学与有限元法的耦合方法. 结合近场动力学方法处理不连续问题的优势以及有限元方法计算效率高的优势,将求解区域划分为两个区域,近场动力学区域和有限元区域. 包含裂纹的区域采用近场动力学方法建模,其他区域采用有限元方法建模. 本文提出的耦合方案实施简单方便,近场动力学区域与有限元区域之间不需要设置重叠区域. 耦合方法通过近场动力学粒子与其域内所有粒子(包括近场动力学粒子和有限元节点)以非局部方式连接,有限元节点与其周围的所有粒子以有限元方式相互作用. 将有限元热传导矩阵和近场动力学粒子相互作用矩阵写入同一整体热传导矩阵中,并采用Guyan缩聚法进一步减小计算量. 分别采用连续介质力学方法和近场动力学方法对一维以及二维温度场算例进行模拟,结果表明,本文的耦合方法具有较高的计算精度和计算效率. 该耦合方案可以进一步拓展到热力耦合条件下含裂纹材料和结构的裂纹扩展问题.
[6] 刘英凯 , 程站起 . 2018 .

功能梯度材料热传导问题的近场动力学模型

. 力学季刊, 39 : 82 - 89

URL[本文引用: 1]摘要

当材料中存在不连续性缺陷的时候,传统的基于连续介质理论的方法在研究热传导问题时存在诸多不便.我们基于近场动力学方法(Peridynamics)建立了功能梯度材料的热传导模型,并且研究了在温度荷载作用下功能梯度材料的温度场的变化表现.该文概述了PD方法应用于热传导问题时的详细理论基础,描述了其建模思路以及计算体系,给出了使用PD方法模拟结构承受温度荷载时的计算格式,讨论了不同梯度形式对功能梯度材料内热传导的影响.算例结果表明:通过PD模型所得到的温度场与解析解吻合较好,证明了PD方法在分析功能梯度材料热传导行为等问题时的可行性.

( Liu Y K , Cheng Z Q . 2018 .

Transient heat conduction model for functionally graded materials based on peridynamics

. Chinese Quarterly of Mechanics, 39 : 82 - 89 ).

URL[本文引用: 1]摘要

当材料中存在不连续性缺陷的时候,传统的基于连续介质理论的方法在研究热传导问题时存在诸多不便.我们基于近场动力学方法(Peridynamics)建立了功能梯度材料的热传导模型,并且研究了在温度荷载作用下功能梯度材料的温度场的变化表现.该文概述了PD方法应用于热传导问题时的详细理论基础,描述了其建模思路以及计算体系,给出了使用PD方法模拟结构承受温度荷载时的计算格式,讨论了不同梯度形式对功能梯度材料内热传导的影响.算例结果表明:通过PD模型所得到的温度场与解析解吻合较好,证明了PD方法在分析功能梯度材料热传导行为等问题时的可行性.
[7] 乔丕忠 , 张勇 , 张恒 , 张律文 . 2017 .

近场动力学研究进展

. 力学季刊, 38 : 1 - 13

DOIURL[本文引用: 2]摘要

近场动力学(Peridynamics或PD)理论基于非局部作用思想,采用空间积分描述物质内部作用,对于从连续到非连续、微观到宏观的力学行为具有统一的表述,数值上天然具有无网格属性和不连续求解功能,在分析不连续,多尺度等问题时展现出了具有优势的适用性和可靠性.本文介绍了近场动力学的发展背景;概述了其理论基础、数值实现过程和计算体系,并在此基础上探讨了近场动力学理论和数值模型的适定性,以及与传统连续介质模型和分子动力学模型进行耦合的可行性;系统分析了近场动力学方法在各个领域上的应用发展现状和趋势,包括静态、动态破坏问题,基于近场动力学的材料模型,以及新兴的疲劳问题研究和多尺度、多物理场的耦合问题;最后对近场动力学方法目前存在的局限性和将来的研究进行了探讨.

( Qiao P Z , Zhang Y , Zhang H , Zhang L W . 2017 .

A review on advances in peridynamics

. Chinese Quarterly of Mechanics, 38 : 1 - 13 ).

DOIURL[本文引用: 2]摘要

近场动力学(Peridynamics或PD)理论基于非局部作用思想,采用空间积分描述物质内部作用,对于从连续到非连续、微观到宏观的力学行为具有统一的表述,数值上天然具有无网格属性和不连续求解功能,在分析不连续,多尺度等问题时展现出了具有优势的适用性和可靠性.本文介绍了近场动力学的发展背景;概述了其理论基础、数值实现过程和计算体系,并在此基础上探讨了近场动力学理论和数值模型的适定性,以及与传统连续介质模型和分子动力学模型进行耦合的可行性;系统分析了近场动力学方法在各个领域上的应用发展现状和趋势,包括静态、动态破坏问题,基于近场动力学的材料模型,以及新兴的疲劳问题研究和多尺度、多物理场的耦合问题;最后对近场动力学方法目前存在的局限性和将来的研究进行了探讨.
[8] 苏伯阳 , 李书欣 , 刘立胜 , 赖欣 , 谷卫敏 . 2018 .

湿热环境下复合材料冲击损伤的近场动力学模拟

. 科学技术与工程, 18 : 201 - 206

URL[本文引用: 1]摘要

研究在湿热条件下复合材料的冲击损伤特征,是复合材料应用在舰船壳体的一个重要基础。现有的有限元方法在分析损伤及裂纹扩展问题中遇到了一定困难,需引入近场动力学(PD)理论,用于分析复合材料湿热冲击损伤。在复合材料近场动力学模型中,定义层内和层间共4种不同作用键;在本构方程中引入湿热伸长率项,改进键伸长率判定和键常数为湿热环境下的形式,建立了湿热环境下复合材料层合板PD模型。基于上述模型,模拟了不同湿热环境下复合材料层合板冲击损伤,并分析冲击速度对湿热处理复合材料层合板吸能性能的影响。结果表明:在冲击速度较低情况下,湿热因素对层合板冲击损伤影响较大;当温度与湿度共同作用时,层合板抵抗冲击能力更强。

( Su B Y , Li S X , Liu L S , Lai X , Gu W M . 2018 .

Peridynamic simulation of impact damage of composite material under hygrothermal environment

. Scicence Technolody and Engineering, 18 : 201 - 206 ).

URL[本文引用: 1]摘要

研究在湿热条件下复合材料的冲击损伤特征,是复合材料应用在舰船壳体的一个重要基础。现有的有限元方法在分析损伤及裂纹扩展问题中遇到了一定困难,需引入近场动力学(PD)理论,用于分析复合材料湿热冲击损伤。在复合材料近场动力学模型中,定义层内和层间共4种不同作用键;在本构方程中引入湿热伸长率项,改进键伸长率判定和键常数为湿热环境下的形式,建立了湿热环境下复合材料层合板PD模型。基于上述模型,模拟了不同湿热环境下复合材料层合板冲击损伤,并分析冲击速度对湿热处理复合材料层合板吸能性能的影响。结果表明:在冲击速度较低情况下,湿热因素对层合板冲击损伤影响较大;当温度与湿度共同作用时,层合板抵抗冲击能力更强。
[9] 孙培德 , 杨东全 , 陈奕柏 . 2007 . 多物理场耦合模型及数值模拟导论. 北京 : 中国科学技术出版社

[本文引用: 1]

( Sun P D , Yang D Q , Chen Y B. 2007 . Introduction to Coupling Models for Multiphysics and Numerical Simulations. Beijing : Science and Technology of China Press) .

[本文引用: 1]

[10] 王超聪 , 刘齐文 , 刘立胜 , 赖欣 . 2017 .

热防护材料烧蚀温度场的近场动力学模拟

. 科学技术与工程, 17 : 172 - 176

URL[本文引用: 1]摘要

热防护材料烧蚀过程是一个典型的非线性、不连续问题。近场动力学理论采用空间积分方程代替偏微分方程,能自然地描述烧蚀面的移动而不需要引入其他临界条件和数值方法。提出了只考虑接触近邻的热键模型,推导了改进的近场动力学瞬态热传导理论,引入烧蚀损伤模型,能够简单准确地捕捉热流,实现了对烧蚀过程的描述。最后对方法的准确性和有效性进行了验证,数值结果与文献中的理论结果和实验结果吻合很好。

( Wang C C , Liu Q W , Liu L S , Lai X . 2017 .

Numerical simulation of ablation temperature for thermal protective composites based on peridynamics

. Scicence Technolody and Engineering, 17 : 172 - 176 ).

URL[本文引用: 1]摘要

热防护材料烧蚀过程是一个典型的非线性、不连续问题。近场动力学理论采用空间积分方程代替偏微分方程,能自然地描述烧蚀面的移动而不需要引入其他临界条件和数值方法。提出了只考虑接触近邻的热键模型,推导了改进的近场动力学瞬态热传导理论,引入烧蚀损伤模型,能够简单准确地捕捉热流,实现了对烧蚀过程的描述。最后对方法的准确性和有效性进行了验证,数值结果与文献中的理论结果和实验结果吻合很好。
[11] 王飞 , 马玉娥 , 郭妍宁 . 2017 .

近场动力学中内核参数对非均匀材料热传导数值解的影响研究

. 西北工业大学学报, 35 : 203 - 207

DOIURL[本文引用: 1]摘要

以近场动力学(peridynamic,简称PD)理论为基础,推导了非均匀材料的热传导方程,给出了PD非均匀物性值的计算方法,数值离散过程和数值计算控制方程。编写了FORTRAN程序,并把计算结果和解析法进行了对比分析,验证了PD法的正确性。重点研究了PD方法中内核参数(等效热导率比例系数、表面修正因子以及形状因子)对非均匀材料热传导数值解的影响。结果表明:等效热导率比例系数、表面修正因子对温度响应影响较大,形状因子的影响基本可以忽略。考虑表面效应且等效热导率取为近场范围内2个材料点上的平均值时,非均匀材料的温度响应与解析解最为接近。

( Wang F , Ma Y E , Guo Y N . 2017 .

Effects of kernel parameters of peridynamic theory on heat conduction numerical solution for non-homogeneous material

. Journal of Northwestern Polytechnical University, 35 : 203 - 207 ).

DOIURL[本文引用: 1]摘要

以近场动力学(peridynamic,简称PD)理论为基础,推导了非均匀材料的热传导方程,给出了PD非均匀物性值的计算方法,数值离散过程和数值计算控制方程。编写了FORTRAN程序,并把计算结果和解析法进行了对比分析,验证了PD法的正确性。重点研究了PD方法中内核参数(等效热导率比例系数、表面修正因子以及形状因子)对非均匀材料热传导数值解的影响。结果表明:等效热导率比例系数、表面修正因子对温度响应影响较大,形状因子的影响基本可以忽略。考虑表面效应且等效热导率取为近场范围内2个材料点上的平均值时,非均匀材料的温度响应与解析解最为接近。
[12] 吴凡 , 李书卉 , 段庆林 , 李熙夔 , 张洪武 . 2017 .

基于近场动力学方法的水力压裂过程数值模拟

. 计算机辅助工程, 26 : 1 - 6

DOIURL[本文引用: 1]摘要

利用近场动力学方法便于处理多裂纹萌生、扩展和分叉的优点,将其应用于页岩水力压裂过程的数值模拟.结合页岩水力压裂机理提出在近场动力学中由破坏度跟踪裂纹扩展路径,并通过在新生成裂纹面法线方向施加水压载荷的裂纹追踪方法,成功模拟单射孔横剖面开裂水压实验以及单射孔和多射孔水平井纵剖面的水力压裂过程,得到压裂导致的裂纹缝网结构.数值结果还表明初始射孔裂纹会显著影响后续的水力压裂过程.

( Wu F , Li S H , Duan Q L , Li X K , Zhang H W . 2017 .

Numerical simulation of hydraulic fracturing process based on peridynamics method

. Computer Aided Engineering, 26 : 1 - 6 ).

DOIURL[本文引用: 1]摘要

利用近场动力学方法便于处理多裂纹萌生、扩展和分叉的优点,将其应用于页岩水力压裂过程的数值模拟.结合页岩水力压裂机理提出在近场动力学中由破坏度跟踪裂纹扩展路径,并通过在新生成裂纹面法线方向施加水压载荷的裂纹追踪方法,成功模拟单射孔横剖面开裂水压实验以及单射孔和多射孔水平井纵剖面的水力压裂过程,得到压裂导致的裂纹缝网结构.数值结果还表明初始射孔裂纹会显著影响后续的水力压裂过程.
[13] 徐涛 , 宋力 . 2007 .

真实破裂过程分析软件与多物理场耦合软件结构力学模块对比研究

. 大连大学学报, 28 : 66 - 71

DOIURL[本文引用: 1]摘要

简要介绍了真实破裂过程分析软件系统(RFPA)和多物理场耦合数值模拟软件系统(COMSOL Multiphysics),并分别运用这两个软件系统对受拉应力作用下带孔平板试件和共心圆轴试件在热应力作用下的受力变形特征进行了数值模拟对比分析,指出真实破裂过程分析软件系统的特色在于对材料破坏过程的分析处理,而多物理场耦合数值模拟软件系统的特色在于对于复杂多场耦合问题的求解,将这两种软件系统各自的特色特点结合起来应用于材料破坏过程中的多场耦合问题分析是以后应当努力发展的方向.

( Xu T , Song L . 2007 .

Comparison study of realistic failure process analysis code and comsol multiphysics code

. Journal of Dalian University, 28 : 66 - 71 ).

DOIURL[本文引用: 1]摘要

简要介绍了真实破裂过程分析软件系统(RFPA)和多物理场耦合数值模拟软件系统(COMSOL Multiphysics),并分别运用这两个软件系统对受拉应力作用下带孔平板试件和共心圆轴试件在热应力作用下的受力变形特征进行了数值模拟对比分析,指出真实破裂过程分析软件系统的特色在于对材料破坏过程的分析处理,而多物理场耦合数值模拟软件系统的特色在于对于复杂多场耦合问题的求解,将这两种软件系统各自的特色特点结合起来应用于材料破坏过程中的多场耦合问题分析是以后应当努力发展的方向.
[14] 章青 , 顾鑫 , 郁杨天 . 2016 .

冲击载荷作用下颗粒材料动态力学响应的近场动力学模拟

. 力学学报, 48 : 56 - 63

DOIURL[本文引用: 1]摘要

The dynamic mechanical behavior of granular materials under impact load is a complex issue. Peridynamics as a new theory based on discontinuous and nonlocal hypothesis regards materials as compositions of massive material points with finite volume and finite mass, and builds an integral governing equation to reflect the motion law of material points. For all the features mentioned above, peridynamics is certainly suitable for describing and analyzing the dynamic behavior of particles. An improved PMB model considering the feature of nonlocal long range force and eliminating the oundary e ect and a repulsive force model at material point level to describe the inter-particle contact interaction are proposed. Then the method is applied to analyze the dynamics responses of tungsten carbide (WC) ceramic granular system su ering from impact loading. Wave velocities of the system were calculated accurately under di erent impact velocities compared with the experiment results. Phenomena of the motion, including translation and rotation, deformation and crushing of particles are reappeared. There are both total damaged particle and slight damaged particle near the impactor, and there are also particles far out from the impactor which are damaged. The extrusion, collision and shear slide between particles result in the particle crushing. The results indicate that the calculation model and analysis method developed here can well reflect the dynamic behavior of granular materials and have large application value.

( Zhang Q , Gu X , Yu Y T . 2016 .

Peridynamics simulation for dynamic response of granular materials under impact loading

. Chinese Journal of Theoretical and Applied Mechanics, 48 : 56 - 63 ).

DOIURL[本文引用: 1]摘要

The dynamic mechanical behavior of granular materials under impact load is a complex issue. Peridynamics as a new theory based on discontinuous and nonlocal hypothesis regards materials as compositions of massive material points with finite volume and finite mass, and builds an integral governing equation to reflect the motion law of material points. For all the features mentioned above, peridynamics is certainly suitable for describing and analyzing the dynamic behavior of particles. An improved PMB model considering the feature of nonlocal long range force and eliminating the oundary e ect and a repulsive force model at material point level to describe the inter-particle contact interaction are proposed. Then the method is applied to analyze the dynamics responses of tungsten carbide (WC) ceramic granular system su ering from impact loading. Wave velocities of the system were calculated accurately under di erent impact velocities compared with the experiment results. Phenomena of the motion, including translation and rotation, deformation and crushing of particles are reappeared. There are both total damaged particle and slight damaged particle near the impactor, and there are also particles far out from the impactor which are damaged. The extrusion, collision and shear slide between particles result in the particle crushing. The results indicate that the calculation model and analysis method developed here can well reflect the dynamic behavior of granular materials and have large application value.
[15] 章青 , 郁杨天 , 顾鑫 . 2016 .

近场动力学与有限元的混合建模方法

. 计算力学学报, 33 : 441 - 448

DOIURL[本文引用: 1]摘要

综述了近场动力学与有限元混合建模方法的研究进展,阐明了各种混合建模方法的基本原理与特点,并重点介绍本课题组在近场动力学与有限元方法混合建模方面的研究工作。现有近场动力学与有限元混合建模方法包括位移协调约束、力耦合、混合函数方法以及子模型方法等,除子模型方法外,都可归结为并行式多尺度分析方法,其基本思想是将计算结构划分为近场动力学子域、有限元子域以及两者的交界区域(或重叠区域、或界面单元、或过渡区域)。子模型方法可归结为显-显分析方法,先采用显式有限元进行整体分析,后采用近场动力学方法对重点区域进行分析。混合建模方法需要着重提高交界区域的计算精度,并且消除虚假力和虚假应力波问题。提出了通过力耦合的近场动力学与有限元混合建模的隐式分析方法,该方法不再设置重叠区,通过杆单元连接近场动力学子域与有限元子域,其中界面上的有限元结点不仅与其所在单元的其他结点发生作用,还通过杆单元与以其为圆心、一定半径的圆域内的其他物质点相互作用。研究表明,本文提出的混合模型和求解方法既能有效解决裂纹扩展等不连续问题,又可提高计算效率,为工程结构破坏问题的计算分析提供一种有效方法。

( Zhang Q , Yu Y T , Gu X . 2016 .

Hybrid modeling methods of peridynamics and finite element method

. Chinese Journal of Computational Mechanics, 33 : 441 - 448 ).

DOIURL[本文引用: 1]摘要

综述了近场动力学与有限元混合建模方法的研究进展,阐明了各种混合建模方法的基本原理与特点,并重点介绍本课题组在近场动力学与有限元方法混合建模方面的研究工作。现有近场动力学与有限元混合建模方法包括位移协调约束、力耦合、混合函数方法以及子模型方法等,除子模型方法外,都可归结为并行式多尺度分析方法,其基本思想是将计算结构划分为近场动力学子域、有限元子域以及两者的交界区域(或重叠区域、或界面单元、或过渡区域)。子模型方法可归结为显-显分析方法,先采用显式有限元进行整体分析,后采用近场动力学方法对重点区域进行分析。混合建模方法需要着重提高交界区域的计算精度,并且消除虚假力和虚假应力波问题。提出了通过力耦合的近场动力学与有限元混合建模的隐式分析方法,该方法不再设置重叠区,通过杆单元连接近场动力学子域与有限元子域,其中界面上的有限元结点不仅与其所在单元的其他结点发生作用,还通过杆单元与以其为圆心、一定半径的圆域内的其他物质点相互作用。研究表明,本文提出的混合模型和求解方法既能有效解决裂纹扩展等不连续问题,又可提高计算效率,为工程结构破坏问题的计算分析提供一种有效方法。
[16] 张振宇 . 2015 .

基于Voronoi图方法的近场动力学键理论及热电耦合理论研究. [硕士论文]

. 武汉: 武汉理工大学

URL[本文引用: 2]摘要

高效的热电器件是热电发电技术应用的核心,而热电耦合效应的精确模拟是热电器件设计的关键,为此国内外学者做了大量的研究工作,并取得了巨大的进展。但到目前为止,在宏观层面,研究工作中采用的数值方法主要是以有限元理论为代表的基于传统连续介质力学的理论,该类方法在处理连续问题时特别有效,但对于非连续场问题则显得有些乏力,如热电器件在服役过程中可能出现裂纹等现象。为此,本文采用近场动力学对热电器件设计中极为关注的热电耦合效应进行了分析,其主要研究内容如下。1.针对经典近场动力学中存在的边界效应问题,本文首次提出了一种基于Voronoi图的近场动力学键理论,该理论通过Voronoi图的方法确定粒子在求解域中的体积及粒子间的作用面。这一新的键理论不仅可以很好地解决经典近场动力学键理论中存在的边界效应问题,同时还突破了其对材料泊松比只能为固定值的限制。2.借鉴上述基于Voronoi图的键理论,建立了含Seebeck效应以及Peltier效应的传热键和导电键模型,以此为基础,结合高斯定理建立了含热电效应的热电耦合近场动力学理论。随后给出了在近场动力学理论中,热电耦合场分析时可能出现的各种边界条件的处理方法。3.详细推导了热电耦合分析的离散格式,建立了以系统矩阵为基础的热电耦合场分析方法,及针对各种边界条件的处理方法。结合算例验证了热电耦合近场动力学理论及数值方法的正确性。4.采用上述数值方法对热电器件的热电转换效率进行了数值模拟,分析了热电器件的几何特征及裂纹对热电器件的发电效率的影响规律。对于完美器件来说,热电材料的热电转换效率主要取决于半导体截面积与顶部导流板的面积之比。

( Zhang Z Y . 2015 .

Study of the voronoi based peridynamic bond theory and thermoelectric coupling theory. [Master Thesis]

. Wuhan: Wuhan University of Technology).

URL[本文引用: 2]摘要

高效的热电器件是热电发电技术应用的核心,而热电耦合效应的精确模拟是热电器件设计的关键,为此国内外学者做了大量的研究工作,并取得了巨大的进展。但到目前为止,在宏观层面,研究工作中采用的数值方法主要是以有限元理论为代表的基于传统连续介质力学的理论,该类方法在处理连续问题时特别有效,但对于非连续场问题则显得有些乏力,如热电器件在服役过程中可能出现裂纹等现象。为此,本文采用近场动力学对热电器件设计中极为关注的热电耦合效应进行了分析,其主要研究内容如下。1.针对经典近场动力学中存在的边界效应问题,本文首次提出了一种基于Voronoi图的近场动力学键理论,该理论通过Voronoi图的方法确定粒子在求解域中的体积及粒子间的作用面。这一新的键理论不仅可以很好地解决经典近场动力学键理论中存在的边界效应问题,同时还突破了其对材料泊松比只能为固定值的限制。2.借鉴上述基于Voronoi图的键理论,建立了含Seebeck效应以及Peltier效应的传热键和导电键模型,以此为基础,结合高斯定理建立了含热电效应的热电耦合近场动力学理论。随后给出了在近场动力学理论中,热电耦合场分析时可能出现的各种边界条件的处理方法。3.详细推导了热电耦合分析的离散格式,建立了以系统矩阵为基础的热电耦合场分析方法,及针对各种边界条件的处理方法。结合算例验证了热电耦合近场动力学理论及数值方法的正确性。4.采用上述数值方法对热电器件的热电转换效率进行了数值模拟,分析了热电器件的几何特征及裂纹对热电器件的发电效率的影响规律。对于完美器件来说,热电材料的热电转换效率主要取决于半导体截面积与顶部导流板的面积之比。
[17] Agwai A . 2011 .

A peridynamic approach for coupled fields. [PhD Thesis]

. Tucson: The University of Arizona.

[本文引用: 3]

[18] Agwai A , Guven I , Madenci E . 2011 .

A new thermomechanical fracture analysis approach for 3D integration technology//IEEE 61st Electronic Components and Technology Conference (ECTC)

, 740 - 745 .

[19] Assefa M , Lai X , Liu L S . 2017 .

Bond based peridynamic formulation for thermoelectric materials

. Materials Science Forum, 883 : 51 - 59 .

DOIURL[本文引用: 1]摘要

Modeling of heat and electrical current flow simultaneously in thermoelectric convertor using classical theories do not consider the influence of defects in the material. This is because traditional methods are developed based on partial differential equations (PDEs) and lead to infinite fluxes and stress fields at the crack tips. The usual way of solving such PDEs is by using numerical technique, like Finite Element Method (FEM). Although FEM is robust and versatile, it is not suitable to model evolving discontinuities since discontinuous fields are mathematically singular at the crack tip and required an external criterion for the prediction of crack growth. In this paper, we follow the concept of peridynamic (PD) theory to overcome the shortcomings above. Therefore, the main aim of this paper is to develop the peridynamic equations for the generalized Fourier090005s and Ohm090005s laws. Furthermore, we derived the peridynamic equations for the conservation of energy and charge for the coupled thermoelectric phenomena.
[20] Assefa M , Lai X , Liu L S , Liao Y . 2017 .

Peridynamic formulation for coupled thermoelectric phenomena

. Advances in Materials Science and Engineering, 2017 : 1 - 10 .

[本文引用: 2]

[21] Bobaru F , Duangpanya M . 2010 .

The peridynamic formulation for transient heat conduction

. International Journal of Heat and Mass Transfer, 53 : 4047 - 4059 .

DOIURL[本文引用: 1]摘要

In bodies where discontinuities, like cracks, emerge and interact, the classical equations for heat and mass transfer are not well suited. We propose a peridynamic model for transient heat (or mass) transfer which is valid when the body undergoes damage or evolving cracks. We use a constructive approach to find the peridynamic formulation for heat transfer and test the numerical convergence to the classical solutions in the limit of the horizon (the nonlocal parameter) going to zero for several one-dimensional problems with different types of boundary conditions. We observe an interesting property of the peridynamic solution: when two m-convergence curves, corresponding to two different horizons, for the solution at a point and an instant intersect, the intersection point is also the exact classical (local) solution. The present formulation can be easily extended to higher dimensions and be coupled with the mechanical peridynamic description for thermomechanical analyses of fracturing bodies, or for heat and mass transfer in bodies with evolving material discontinuities.
[22] Bobaru F , Duangpanya M . 2012 .

A peridynamic formulation for transient heat conduction in bodies with evolving discontinuities

. Journal of Computational Physics, 231 : 2764 - 2785 .

DOIURL[本文引用: 1]

[23] Bobaru F , Foster J T , Geubelle P H , Silling S A . 2016 .

Handbook of Peridynamic Modeling

. Raton: CRC press.

[本文引用: 2]

[24] Chen Z G , Bobaru F . 2015 .

Selecting the kernel in a peridynamic formulation: A study for transient heat diffusion

. Computer Physics Communications, 197 : 51 - 60 .

DOIURL摘要

The kernel in a peridynamic diffusion model represents the detailed interaction between points inside the nonlocal region around each material point. Several versions of the kernel function have been proposed. Although solutions associated with different kernels may all converge, under the appropriate discretization scheme, to the classical model when the horizon goes to zero, their convergence behavior varies. In this paper, we focus on the particular one-point Gauss quadrature method of spatial discretization of the peridynamic diffusion model and study the convergence properties of different kernels with respect to convergence to the classical, local, model for transient heat transfer equation in 1D, where exact representation of geometry is available. The one-point Gauss quadrature is the preferred method for discretizing peridynamic models because it leads to a meshfree model, well suited for problems with damage and fracture. We show the equivalency of two definitions for the peridynamic heat flux. We explain an apparent paradox and discuss a common pitfall in numerical approximations of nonlocal models and their convergence to local models. We also analyze the influence of two ways of imposing boundary conditions and that of the “skin effect” on the solution. We explain an interesting behavior of the peridynamic solutions for different horizon sizes, the crossing ofm-convergence curves at the classical solution value that happens for one of the ways of implementing the classical boundary conditions. The results presented here provide practical guidance in selecting the appropriate peridynamic kernel that makes the one-point Gauss quadrature an “asymptotically compatible” scheme. These results are directly applicable to any diffusion-type model, including mass diffusion problems.
[25] Chen Z G , Bobaru F . 2015 .

Peridynamic modeling of pitting corrosion damage

. Journal of the Mechanics and Physics of Solids, 78 : 352 - 381 .

DOIURL[本文引用: 1]摘要

61First model to simulate sub-surface corrosion damage in corrosion.61Corrosion reaction as nonlocal-diffusion plus phase-change in metal/electrolyte.61Activation, IR and diffusion-controlled corrosion regimes predicted with single model.61Damage evolution coupled with metal corrosion is modeled in 1D, 2D and 3D.61Mircostructural heterogeneities and overpotential shown to affect corrosion damage.
[26] Chen Z G , Zhang G F , Bobaru F . 2016 .

The influence of passive film damage on pitting corrosion

. Journal of The Electrochemical Society, 163 : 19 - 24 .

[本文引用: 2]

[27] Chen H L , Hu Y L , Spencer B W . 2016 .

A MOOSE-based implicit peridynamic thermomechanical model

// ASME 2016 International Mechanical Engineering Congress and Exposition, 2016 : V009T12A072.

[28] Chen H L , Hu Y L , Spencer B W . 2017 .

Peridynamics using irregular domain discretization with moose-based implementation//ASME 2017 International Mechanical Engineering Congress and Exposition

, 2017 : V009T12A067-V009T12A067.

[本文引用: 1]

[29] De Meo D , Oterkus E . 2017 .

Finite element implementation of a peridynamic pitting corrosion damage model

. Ocean Engineering, 135 : 76 - 83 .

DOIURL[本文引用: 1]

[30] De Meo D , Diyaroglu C , Zhu N , Oterkus E , Siddiq M A . 2016 .

Modelling of stress-corrosion cracking by using peridynamics

. International Journal of Hydrogen Energy, 41 : 6593 - 6609 .

DOIURL[本文引用: 1]摘要

61A novel multiphysics peridynamic framework is used to predict crack initiation, propagation and branching due to stress corrosion cracking.61The model consists of a 2D polycrystalline pre-cracked thin steel plate subjected to mechanical load and exposed to a corrosive aqueous solution.61Novel micro-mechanical and hydrogen grain boundary diffusion peridynamic formulations are introduced.61The material is modelled at the microscale and first principle calculations are used to predict the toughness reduction of the material due to grain boundary hydrogen diffusion.61A good agreement between numerical and experimental results is found.
[31] Delgoshaie A H , Meyer D W , Jenny P , Tchelepi H A . 2015 .

Non-local formulation for multiscale flow in porous media

. Journal of Hydrology, 531 : 649 - 654 .

DOIURL[本文引用: 1]摘要

The multiscale nature of geological formations is reflected in the flow and transport behaviors of the pore fluids. For example, multiple pathways between different locations in the porous medium are usually present. The topology, length, and strength of these flow paths can vary significantly, and the total flow at a given location can be the result of contributions from a wide range of pathways between the points of interest. We use a high-resolution pore network of a natural porous formation as an example of the multiscale connectivity of the pore space. A single continuum model can capture the contributions from all the flow paths properly only if the control volume (computational cell) is much larger than the longest pathway. However, depending on the densities and lengths of these long pathways, choosing the appropriate size of the control volume that allows for a single continuum description of the properties, such as conductivity and transmissibility, may conflict with the desire to resolve the flow field properly. To capture the effects of the multiscale pathways on the flow, a non-local continuum model is described. The model can represent non-local effects, for which Darcy law is not valid. In the limit where the longest connections are much smaller than the size of the control volume, the model is consistent with Darcy law. The non-local model is used to describe the flow in complex pore networks. The pressure distributions obtained from the non-local model are compared with pore-network flow simulations, and the results are in excellent agreement. Importantly, such multiscale flow behaviors cannot be represented using the local Darcy law.
[32] Diyaroglu C , Oterkus S , Oterkus E , Madenci E . 2017 .

Peridynamic modeling of diffusion by using finite-element analysis. IEEE Transactions on Components,

Packaging and Manufacturing Technology, 7 : 1823 - 1831 .

DOIURL[本文引用: 1]摘要

Diffusion modeling is essential in understanding many physical phenomena such as heat transfer, moisture concentration, and electrical conductivity. In the presence of material and geometric discontinuities and nonlocal effects, a nonlocal continuum approach, named peridynamics (PD), can be advantageous over the traditional local approaches. PD is based on integro-differential equations without including any spatial derivatives. In general, these equations are solved numerically by employing meshless discretization techniques. Although fundamentally different, commercial finite-element software can be a suitable platform for PD simulations that may result in several computational benefits. Hence, this paper presents the PD diffusion modeling and implementation procedure in a widely used commercial finite-element analysis software, ANSYS. The accuracy and capability of this approach is demonstrated by considering several benchmark problems.
[33] Diyaroglu C , Oterkus S , Oterkus E , Madenci E , Han S , Hwang Y . 2017 .

Peridynamic wetness approach for moisture concentration analysis in electronic packages

. Microelectronics Reliability, 70 : 103 - 111 .

DOIURL[本文引用: 2]摘要

Within the finite element framework, a commonly accepted indirect approach employs the concept of normalized concentration to compute moisture concentration. It is referred to as etness approach. If the saturated concentration value is not dependent on temperature or time, the wetness equation is analogous to the standard diffusion equation whose solution can be constructed by using any commercial finite element analysis software such as ANSYS. However, the time dependency of saturated concentration requires special treatment under temperature dependent environmental conditions such as reflow process. As a result, the wetness equation is not directly analogous to the standard diffusion equation. This study presents the peridynamic wetness modeling for time dependent saturated concentration for computation of moisture concentration in electronic packages. It is computationally efficient as well as easy to implement without any iterations in each time step. Numerical results concerning the one-dimensional analysis illustrate the accuracy of this approach. Moisture concentration calculation in a three-dimensional electronic package configuration with many different material layers demonstrates its robustness.
[34] Du Q , Gunzburger M , Lehoucq R B , Zhou K . 2012 .

Analysis and approximation of nonlocal diffusion problems with volume constraints

. SIAM Review, 54 : 667 - 696 .

DOIURL[本文引用: 1]

[35] Du Q , Gunzburger M , Lehoucq R B , Zhou K . 2013 .

A nonlocal vector calculus, nonlocal volume-constrained problems, and nonlocal balance laws

. Mathematical Models and Methods in Applied Sciences, 23 : 493 - 540 .

DOIURL[本文引用: 1]摘要

A vector calculus for nonlocal operators is developed, including the definition of nonlocal divergence, gradient, and curl operators and the derivation of the corresponding adjoint operators. Nonlocal analogs of several theorems and identities of the vector calculus for differential operators are also presented. Relationships between the nonlocal operators and their differential counterparts are established, first in a distributional sense and then in a weak sense by considering weighted integrals of the nonlocal adjoint operators. The operators of the nonlocal calculus are used to define volume-constrained problems that are analogous to elliptic boundary-value problems for differential operators; this is demonstrated via some examples. Another application discussed is the posing of abstract nonlocal balance laws and deriving the corresponding nonlocal field equations; this is demonstrated for heat conduction and the peridynamics model for continuum mechanics.
[36] D'Antuono P , Morandini M . 2017 .

Thermal shock response via weakly coupled peridynamic thermo-mechanics

. International Journal of Solids and Structures, 129 : 74 - 89 .

DOIURL[本文引用: 1]

[37] Edmiston J K . 2015 .

Development of a geoperidynamic model for hydraulic fracture//In 49th US Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association

.

[本文引用: 1]

[38] Farhat C , Park K C , Dubois-Pelerin Y . 1991 .

An unconditionally stable staggered algorithm for transient finite element analysis of coupled thermoelastic problems

. Computer Methods in Applied Mechanics and Engineering, 85 : 349 - 365 .

DOIURL[本文引用: 1]摘要

An unconditionally stable second order accurate implicit-implicit staggered procedure for the finite element solution of fully coupled thermoelasticity transient problems is proposed. The procedure is stabilized with a semi-algebraic augmentation technique. A comparative cost analysis reveals the superiority of the proposed computational strategy to other conventional staggered procedures. Numerical examples of one- and two-dimensional thermomechanical coupled problems demonstrate the accuracy of the proposed numerical solution algorithm.
[39] Gerstle W H , Silling S A , Read D , Tewary V , Lehoucq R B . 2008 .

Peridynamic simulation of electromigration

. CMC-Computers Materials & Continua, 8 : 75 - 92 .

[本文引用: 1]

[40] Gu X , Zhang Q , Huang D , Yu Y T . 2016 .

Wave dispersion analysis and simulation method for concrete SHPB test in peridynamics

. Engineering Fracture Mechanics, 160 : 124 - 137 .

DOIURL[本文引用: 1]摘要

The Split Hopkinson Pressure Bar (SHPB) technique is a widely used method for measuring mechanical properties of materials subjected to high-strain-rate loads, while it is difficult to simulate the whole testing process including high-rate deformation, local damage and failure of materials by the common numerical methods. In this paper, an improved numerical approach based on the non-local peridynamic (PD) theory is employed to study the elastic wave dispersion and propagation and the impact failure of concrete Brazilian discs in SHPB test. Meanwhile, an improved PMB (Prototype Microelastic Brittle) model and an implementation method of the contact-impact process are introduced. In PD, the nonlocal long-range force controls the numerical dispersion of wave through different material point sizes and horizon sizes. The numerical dispersion can result in a slight distortion of the wave speed and crack propagation speed, which is not conductive to failure analysis of solids. The improved PMB model can effectively lessen the numerical dispersion compared with the original PMB model. Furthermore, the PD simulation of concrete Brazilian disc SHPB test can reproduce damage accumulation and progressive failure of a specimen, and produce typical final failure pattern. The PD simulation method for SHPB test can be used to analyze the dynamic response of solids suffering impact load.
[41] Gu X , Zhang Q , Xia X Z . 2017 . Voronoi-based peridynamics and cracking analysis with adaptive refinement. International Journal for Numerical Methods in Engineering, 112 : 2087 -- 2109 .

[本文引用: 1]

[42] Gu X , Madenci E , Zhang Q . 2018 .

Revisit of non-ordinary state-based peridynamics

. Engineering Fracture Mechanics, 190 : 31 - 52 .

DOIURL[本文引用: 1]摘要

The force density vector in the Non-Ordinary State-Based (NOSB) PeriDynamics (PD) replaces the internal force vector derived from the divergence of the stress tensor in the classical (local) stress equilibrium equations. It involves only the non-local form of the first order derivatives of stress and displacement components. Inherent in the NOSB PD formulation is the presence of oscillations especially in the regions of steep displacement gradients. This study introduces an alternative form of the force density vector by considering the internal force vector derived directly from the displacement equilibrium equations. It involves only the non-local form of the second-order derivatives of the displacement components. The numerical results from this form of the force density vector do not present any oscillations. Therefore, it is referred to as the Refined NOSB (RNOSB) PD. The simulations concern the comparisons of NOSB and RNOSB PD predictions for an isotropic plate with or without a notch or a crack under quasi-static and dynamic tensile loading. The RNOSB PD proves to be effective and accurate for cracking and fracture analysis without any numerical instability.
[43] Giannakeas I N , Papathanasiou T K , Bahai H . 2018 .

Simulation of thermal shock cracking in ceramics using bond-based peridynamics and FEM

. Journal of the European Ceramic Society, 38 : 3037 - 3048 .

DOIURL[本文引用: 1]

[44] Han S W , Diyaroglu C , Oterkus S , Madenci E , Oterkus E , Hwang Y , Seol H . 2016 . Peridynamic direct concentration approach by using ANSYS//IEEE 66th Electronic Components and Technology Conference (ECTC), 2016 : 544 - 549 .

[本文引用: 1]

[45] Hu Y L , Chen H L , Spencer B W , Madenci E . 2018

Thermomechanical peridynamic analysis with irregular non-uniform domain discretization

. Engineering Fracture Mechanics, 197 : 92 - 113 .

DOIURL[本文引用: 2]摘要

Irregular non-uniform discretization of the solution domain in models based on peridynamic theory can improve computational efficiency by allowing local refinement and remove mesh bias effects on crack initiation and propagation. However, the use of such discretizations generally requires adjustment of the classical peridynamic material parameters and usage of a variable horizon which results in the so-called ghost force effect in the interactions between differing horizons. This study presents a generalization of the original bond-based and ordinary state-based peridynamic models to permit the use of irregular non-uniform domain discretizations, in which the strain energy and thermal potential associated with a bond between two material points is split into two parts based on volumetric ratios. This division is potentially different for each bond due to the presence of irregular non-uniform discretization. The validity and accuracy of this proposed approach is established using several benchmark examples, and its applicability to real engineering problems is demonstrated by modeling thermally induced cracking in a three-dimensional nuclear fuel pellet.
[46] Ishimoto J , Sato T , Combescure A . 2017 .

Computational approach for hydrogen leakage with crack propagation of pressure vessel wall using coupled particle and Euler method

. International Journal of Hydrogen Energy, 42 : 10656 - 10682 .

DOIURL[本文引用: 1]摘要

61Hydrogen leakage accompany with tank wall crack propagation was newly analyzed.61Coupled particle and Eulerian methods has been developed for hydrogen safety problems.61Peridynamics model was verified as effective method for hydrogen tank crack analysis.61Volume concentration of gaseous hydrogen leakage from crack was computationally predicted.
[47] Jabakhanji R . 2013 .

Peridynamic modeling of coupled mechanical deformations and transient flow in unsaturated soils. [PhD Thesis]

. West Lafayette: Purdue University.

[本文引用: 3]

[48] Jabakhanji R , Mohtar R H . 2015 .

A peridynamic model of flow in porous media

. Advances in Water Resources, 78 : 22 - 35 .

DOIURL[本文引用: 1]摘要

This paper presents a nonlocal, derivative free model for transient flow in unsaturated, heterogeneous, and anisotropic soils. The formulation is based on the peridynamic model for solid mechanics. In the proposed model, flow and changes in moisture content are driven by pairwise interactions with other points across finite distances, and are expressed as functional integrals of the hydraulic potential field. Peridynamic expressions of the rate of change in moisture content, moisture flux, and flow power are derived, as are relationships between the peridynamic and the classic hydraulic conductivities; in addition, the model is validated. The absence of spacial derivatives makes the model a good candidate for flow simulations in fractured soils and lends itself to coupling with peridynamic mechanical models for simulating crack formation triggered by shrinkage and swelling, and assessing their potential impact on a wide range of processes, such as infiltration, contaminant transport, and slope stability.
[49] Jafarzadeh S , Chen Z G , Bobaru F . 2017 .

Peridynamic modeling of repassivation in pitting corrosion of stainless steel

. Corrosion, 74 : 393 - 414 .

[本文引用: 1]

[50] Jafari A , Bahaaddini R , Jahanbakhsh H . 2018 .

Numerical analysis of peridynamic and classical models in transient heat transfer, employing Galerkin approach

. Heat Transfer---Asian Research, 47 : 531 - 555 .

DOIURL[本文引用: 1]摘要

react-text: 379 The kernel in a peridynamic diffusion model represents the detailed interaction between points inside the nonlocal region around each material point. Several versions of the kernel function have been proposed. Although solutions associated with different kernels may all converge, under the appropriate discretization scheme, to the classical model when the horizon goes to zero, their... /react-text react-text: 380 /react-text [Show full abstract]
[51] Jenny P , Meyer D W . 2017 .

Non-local generalization of Darcy's law based on empirically extracted conductivity kernels

. Computational Geosciences, 21 : 1281 - 1288 .

DOIURL[本文引用: 1]摘要

In the context of flow and transport in porous and fractured media, Darcy-based continuum models, while computationally inexpensive, are of limited use when the scale of interest is of similar size or smaller than the characteristic network connection length. Recently, we have outlined a non-local Darcy model that bridges the gap between network and Darcy-based descriptions. This formulation is able to account for non-local pressure effects that are not accounted for in a classical Darcy description. At the heart of this non-local flow formulation is a conductivity distribution or kernel that is related to the scalar permeability in the classical Darcy law. In this paper, ensembles of flow networks are considered, of which the necessary statistical information is assumed to be known. In order to relate the conductivity distribution with the flow statistics, a stochastic transport model for fluid particles, termed generalized continuous time random walk (g-CTRW), which is a generalization of correlated continuous time random walk, is introduced. Note that similar assumptions as for correlated CTRW are made, i.e., that lengths and velocities of connections between successive nodes along the trajectories can be described by Markov processes. In order to proceed with a theoretical analysis, a Boltzmann equation is presented, which is consistent with the particle time marching algorithm based on g-CTRW. An important outcome of the analysis is an expression relating the joint probability density function of velocity and connection length in the networks with the conductivity kernel. A numerical, stationary flow example demonstrates how the kernel can be extracted. Further, an algorithm is proposed to compute consistent velocity statistics, mean pressure distribution, and spatially varying conductivity kernel in the case of non-stationary flow. This coupled iterative approach is an attempt to consistently compute stochastic flow and transport in large network ensembles.
[52] Jeon B S , Stewart R J , Ahmed I Z . 2015 .

Peridynamic simulations of brittle structures with thermal residual deformation: Strengthening and structural reactivity of glasses under impacts//Proceedings of the Royal Society A: Mathematical Physical and Engineering Sciences

, 471 : 20150231 .

DOIURL[本文引用: 1]摘要

In glass research, the effect and influence of pre-deformation by thermal or chemical treatment is of great importance when configuring different mechanical properties or scratch resistance on the surface of glasses. In particular, such pre-deformation affects dynamic fracture or damage evolution when glass structures are under impact or collision conditions. Peridynamics provides a seamless approach for the simulation of dynamic damage evolution of the system under aggressive environments. Revising the pair interaction of each material point, the effect of pre-deformation is implemented, and the corresponding damage evolution can be simulated conveniently. Our approach is composed of two steps: first, a static solution is found via energy minimization with thermal boundary conditions in the peridynamic platform. Second, comparing the initial and the pre-deformed structures from the energy minimization, the effect of residual deformation, strengthening and reactive behaviour of brittle structures are seamlessly simulated. The developed methods are applied to the Prince Rupert drop and Bologna vial, which are classic examples of strengthened glasses. This study reports the first complete and successful simulation of dynamic behaviour of strengthened glasses, and a significant contribution in simulating residual stress behaviour in any material.
[53] Katiyar A , Foster J T , Ouchi H , Sharma M M . 2014 .

A peridynamic formulation of pressure driven convective fluid transport in porous media

. Journal of Computational Physics, 261 : 209 - 229 .

DOIURL[本文引用: 3]摘要

A general state-based peridynamic formulation is presented for convective single-phase flow of a liquid of small and constant compressibility in heterogeneous porous media. In addition to local fluid transport, possible anomalous diffusion due to non-local fluid transport is considered and simulated. The governing integral equations of the peridynamic formulation are computationally easier to solve in domains with discontinuities than the traditional conservation models containing spatial derivatives. A bond-based peridynamic formulation is also developed and demonstrated to be a special case of the state-based formulation. The non-local model does not assume continuity in the field variables, satisfies mass conservation over an arbitrary bounded body and approaches the corresponding local model as the non-local region goes to zero. The exact solution of the local model closely matches the non-local model for a classical two-dimensional flow problem with fluid sources and sinks and for both Neumann and Dirichlet boundary conditions. The model is shown to capture arbitrary flow discontinuities/heterogeneities without any fundamental changes to the model and with small incremental computational costs.
[54] Kilic B , Madenci E . 2009 .

Prediction of crack paths in a quenched glass plate by using peridynamic theory

. International Journal of Fracture, 156 : 165 - 177 .

DOIURL[本文引用: 3]摘要

The peridynamic theory is employed to predict crack growth patterns in quenched glass plates previously considered for an experimental investigation. The plates containing single and multiple pre-existing initial cracks are simulated to investigate the effects of peridynamic and experimental parameters on the crack paths. The critical stretch value in the peridynamic theory and the gap size between the heat reservoirs are determined to be the most significant parameters. The simulation results are in good agreement with the experimental observations published in the literature.
[55] Kilic B , Madenci E . 2010 .

Peridynamic Theory for Thermomechanical Analysis

. IEEE Transactions on Advanced Packaging, 33 : 97 - 105 .

DOIURL[本文引用: 1]摘要

Thermomechanical modeling for interconnects and electronic packages is a difficult challenge, especially for material interfaces and films under 1 mum dimension. Understanding and prediction of their mechanical failure require the simulation of material behavior in the presence of multiple length scales. However, the classical continuum theory is not capable of predicting failure without a posterior analysis with an external crack growth criteria and treats the interfaces having zero thickness. A new nonlocal continuum theory referred to as peridynamic theory offers the ability to predict failure at these length scales. This study presents a new response function as part of the peridynamic theory to include thermal loading. After validating this response function by comparing against the displacement predictions in benchmark problems against those of finite element method, the peridynamic theory is used to predict damage initiation and propagation in regions having dissimilar materials due to thermomechanical loading.
[56] Le Q V , Chan W K , Schwartz J . 2014 .

A two-dimensional ordinary, state-based peridynamic model for linearly elastic solids

. International Journal for Numerical Methods in Engineering, 98 : 547 - 561 .

DOIURL[本文引用: 1]摘要

SUMMARYPeridynamics is a non-local mechanics theory that uses integral equations to include discontinuities directly in the constitutive equations. A three-dimensional, state-based peridynamics model has been developed previously for linearly elastic solids with a customizable Poisson's ratio. For plane stress and plane strain conditions, however, a two-dimensional model is more efficient computationally. Here, such a two-dimensional state-based peridynamics model is presented. For verification, a 2D rectangular plate with a round hole in the middle is simulated under constant tensile stress. Dynamic relaxation and energy minimization methods are used to find the steady-state solution. The model shows m-convergence and -convergence behaviors when m increases and decreases. Simulation results show a close quantitative matching of the displacement and stress obtained from the 2D peridynamics and a finite element model used for comparison. Copyright 2014 John Wiley & Sons, Ltd.
[57] Liao Y , Liu L S , Liu Q W , Lai X , Assefa M , Liu J G . 2017 .

Peridynamic simulation of transient heat conduction problems in functionally gradient materials with cracks

. Journal of Thermal Stresses, 40 : 1484 - 1501 .

DOIURL摘要

(2017). Peridynamic simulation of transient heat conduction problems in functionally gradient materials with cracks. Journal of Thermal Stresses: Vol. 40, No. 12, pp. 1484-1501.
[58] Madenci E , Oterkus E . 2014 .

Peridynamic Theory and Its Applications

. New York: Springer.

DOIURL[本文引用: 2]摘要

Abstract This book presents the peridynamic theory, which provides the capability for improved modeling of progressive failure in materials and structures, and paves the way for addressing multi-physics and multi-scale problems. The book provides students and researchers with a theoretical and practical knowledge of the peridynamic theory and the skills required to analyze engineering problems. The text may be used in courses such as Multi-physics and Multi-scale Analysis, Nonlocal Computational Mechanics, and Computational Damage Prediction. Sample algorithms for the solution of benchmark problems are available so that the reader can modify these algorithms, and develop their own solution algorithms for specific problems. Students and researchers will find this book an essential and invaluable reference on the topic. 2014 Springer Science+Business Media New York. All rights are reserved.
[59] Madenci E , Oterkus S . 2017

a. Ordinary state-based peridynamics for thermoviscoelastic deformation

. Engineering Fracture Mechanics, 175 : 31 - 45 .

DOIURL[本文引用: 1]摘要

This study presents the ordinary state-based peridynamic (PD) constitutive relations for viscoelastic deformation under mechanical and thermal loads. The behavior of the viscous material is modeled in terms of Prony series. The constitutive constants are the same as those of the classical history-integral model, and they are also readily available from relaxation tests. The state variables are conjugate to the PD elastic stretch measures; hence, they are consistent with the kinematic assumptions of the elastic deformation. The PD viscoelastic deformation analysis successfully captures the relaxation behavior of the material. The numerical results concern first the verification problems, and subsequently, a double-lap joint with a viscoelastic adhesive where failure nucleates and grows.
[60] Madenci E , Oterkus S . 2017

b. Peridynamic modeling of thermo-oxidative damage evolution in a composite lamina

// In 58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2017 - 0197 .

[本文引用: 1]

[61] Mella R , Wenman M R . 2015 .

Modelling explicit fracture of nuclear fuel pellets using peridynamics

. Journal of Nuclear Materials, 467 : 58 - 67 .

DOIURL[本文引用: 1]摘要

Three dimensional models of explicit cracking of nuclear fuel pellets for a variety of power ratings have been explored with peridynamics, a non-local, mesh free, fracture mechanics method. These models were implemented in the explicitly integrated molecular dynamics code LAMMPS, which was modified to include thermal strains in solid bodies. The models of fuel fracture, during initial power transients, are shown to correlate with the mean number of cracks observed on the inner and outer edges of the pellet, by experimental post irradiation examination of fuel, for power ratings of 10 and 15 W g 1UO2. The models of the pellet show the ability to predict expected features such as the mid-height pellet crack, the correct number of radial cracks and initiation and coalescence of radial cracks. This work presents a modelling alternative to empirical fracture data found in many fuel performance codes and requires just one parameter of fracture strain. Weibull distributions of crack numbers were fitted to both numerical and experimental data using maximum likelihood estimation so that statistical comparison could be made. The findings show P-values of less than 0.5% suggesting an excellent agreement between model and experimental distributions.
[62] Multiphysics CO . 2012 .

Comsol Multiphysics User's Guide, Version 4.3a

.

[63] Nadimi S , Miscovic I , McLennan J . 2016 .

A 3D peridynamic simulation of hydraulic fracture process in a heterogeneous medium

. Journal of Petroleum Science and Engineering, 145 : 444 - 452 .

DOIURL[本文引用: 1]摘要

61Utility of the peridynamics theory (PD) in modeling the hydraulic fracture phenomenon.61Suitable for modeling coupled complex thermal-hydrologic-geomechanical process without using additional failure criteria or crack growth laws.61Using of integral equations, instead of the partial differential equations used in classical formulations.61Application of the peridynamic theory in simulation hydraulic fracturing in a heterogeneous medium.
[64] Oterkus S . 2015 .

Peridynamics for the solution of multiphysics problems. [PhD Thesis]

. Tucson: The University of Arizona.

URL[本文引用: 4]摘要

This study presents peridynamic field equations for mechanical deformation, thermal diffusion, moisture diffusion, electric potential distribution, porous flow and atomic diffusion in either an uncoupled or a coupled manner. It is a nonlocal theory with an internal length parameter. Therefore, it can capture physical phenomenon for the problems which include non-local effects and are not suitable for classical theories. Moreover, governing equations of peridynamics are based on integro-differential equations which permits the determination of the field variable in spite of discontinuities. Inherent with the nonlocal formulations, the imposition of the boundary conditions requires volume constraints. This study also describes the implementation of the essential and natural boundary conditions, and demonstrates the accuracy of their implementation. Solutions coupled field problems concerning plastic deformations, thermomechanics, hygrothermomechanics, hydraulic fracturing, thermal cracking of fuel pellet and electromigration are constructed. Their comparisons with the finite element predictions establish the validity of the PD field equations for coupled field analysis.
[65] Oterkus S , Fox J , Madenci E . 2013 . Simulation of electro-migration through peridynamics//IEEE 63rd Electronic Components and Technology Conference (ECTC), 2013 : 1488 - 1493 .

[本文引用: 1]

[66] Oterkus S , Madenci E . 2013 .

Crack growth prediction in fully-coupled thermal and deformation fields using peridynamic theory

// In 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2013 - 1477 .

DOIURL[本文引用: 2]摘要

This study presents a fully coupled peridynamic thermomechanical equations, and their nondimensional form for two-dimensional analysis. Peridynamic solutions to both the thermal and deformation field equations are verified against the known solutions. Subsequently, the coupled thermal and structural response of a plate with a pre-existing crack is investigated. It accurately predicts the temperature rise at the crack tips as the crack propagates.
[67] Oterkus S , Madenci E . 2014 .

Fully coupled thermomechanical analysis of fiber reinforced composites using peridynamics

// In 55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2014 - 0694 .

URL

[68] Oterkus S , Madenci E . 2017 .

Peridynamic modeling of fuel pellet cracking

. Engineering Fracture Mechanics, 176 : 23 - 37 .

DOIURL[本文引用: 4]摘要

This study presents the peridynamic simulation of thermal cracking behaviour in uranium dioxide, UO2fuel pellets that are used in light water reactors (LWR). The performance of the reactor is influenced by the thermo-mechanical behaviour of the pellets. During the fission process, the pellets are subjected to high temperature gradients, and the oxygen diffusion significantly affects the temperature distribution. Therefore, a coupled analysis of temperature and oxygen diffusions and deformation is unavoidable in order to predict accurate cracking behavior in a fuel pellet. The accuracy of the predictions is verified qualitatively by comparing with the previous studies.
[69] Oterkus S , Madenci E , Agwai A . 2014

a. Peridynamic thermal diffusion

. Journal of Computational Physics, 265 : 71 - 96 .

DOIURL[本文引用: 1]

[70] Oterkus S , Madenci E , Agwai A . 2014

b. Fully coupled peridynamic thermomechanics

. Journal of the Mechanics and Physics of Solids, 64 : 1 - 23 .

DOIURL[本文引用: 3]摘要

This study concerns the derivation of the coupled peridynamic (PD) thermomechanics equations based on thermodynamic considerations. The generalized peridynamic model for fully coupled thermomechanics is derived using the conservation of energy and the free-energy function. Subsequently, the bond-based coupled PD thermomechanics equations are obtained by reducing the generalized formulation. These equations are also cast into their nondimensional forms. After describing the numerical solution scheme, solutions to certain coupled thermomechanical problems with known previous solutions are presented.
[71] Oterkus S , Madenci E , Oterkus E , Hwang Y , Bae J , Han S . 2014c . Hygro-thermo-mechanical analysis and failure prediction in electronic packages by using peridynamics//IEEE 64th Electronic Components and Technology Conference (ECTC), 2014 : 973 - 982 .

[本文引用: 6]

[72] Oterkus S , Madenci E , Oterkus E . 2017 .

Fully coupled poroelastic peridynamic formulation for fluid-filled fractures

. Engineering Geology, 225 : 19 - 28 .

DOIURL摘要

61A new fully coupled poroelastic peridynamic formulation is developed.61The formulation is also suitable for fluid-filled fractures.61The formulation is validated by considering one- and two-dimensional consolidation problems.61A hydraulically pressurized crack case is analyzed.
[73] Ouchi H , Katiyar A , York J , Foster J T , Sharma M M . 2015

a. A fully coupled porous flow and geomechanics model for fluid driven cracks: A peridynamics approach

. Computational Mechanics, 55 : 561 - 576 .

DOIURL[本文引用: 2]摘要

A state-based non-local peridynamic formulation is presented for simulating fluid driven fractures in an arbitrary heterogeneous poroelastic medium. A recently developed peridynamic formulation of porous flow has been coupled with the existing peridynamic formulation of solid and fracture mechanics resulting in a peridynamic model that for the first time simulates poroelasticity and fluid-driven fracture propagation. This coupling is achieved by modeling the role of pore pressure on the deformation of porous media and vice versa through porosity variation with medium deformation, pore pressure and total mean stress. The poroelastic model is verified by simulating the one-dimensional consolidation of fluid saturated rock. An additional porous flow equation with material permeability dependent on fracture width is solved to simulate fluid flow in the fractured region. Finally, single fluid-driven fracture propagation with a two-dimensional plane strain assumption is simulated and verified against the corresponding classical analytical solution.
[74] Ouchi H , Katiyar A , Foster J T , Sharma M M . 2015 b.

A peridynamics model for the propagation of hydraulic fractures in heterogeneous, naturally fractured reservoirs//In SPE Hydraulic Fracturing Technology Conference 2015

. Society of Petroleum Engineers.

[本文引用: 3]

[75] Ouchi H . 2016 .

Development of peridynamics-based hydraulic fracturing model for fracture growth in heterogeneous reservoirs. [PhD Thesis]

. Austin: University of Texas.

[本文引用: 1]

[76] Ouchi H , Agrawal S , Foster J T , Sharma MM . 2017

a. Effect of small scale heterogeneity on the growth of hydraulic fractures//In SPE Hydraulic Fracturing Technology Conference and Exhibition

. Society of Petroleum Engineers.

[本文引用: 1]

[77] Ouchi H , Foster J T , Sharma M M . 2017

b. Effect of reservoir heterogeneity on the vertical migration of hydraulic fractures

. Journal of Petroleum Science and Engineering, 151 : 384 - 408 .

DOIURL[本文引用: 1]摘要

The effect of different types of vertical reservoir heterogeneities on fracture propagation was systematically investigated. A fully 3-D, poroelastic model that does not prescribe the crack propagation path is used to estimate the fracture geometry in vertically heterogeneous rocks. Complex fracture trajectories are shown to occur and this limits fracture height growth. It is shown that the presence of bedding planes, layer interfaces and even smaller scale heterogeneities can lead to fracture turning, kinking or branching. The mechanisms that control these characteristic fracture propagation behaviors (“turning”, “kinking”, and “branching”) near the layer interface are explored in detail. In layered systems, the mechanical property contrast between layers, the dip angle, the stress contrast and the mechanical properties of the layer interface all play an important role in controlling the fracture trajectory. Conditions under which each type of behavior is expected to occur are clearly delineated.
[78] Prakash N , Seidel G D . 2016 .

Electromechanical peridynamics modeling of piezoresistive response of carbon nanotube nanocomposites

. Computational Materials Science, 113 : 154 - 170 .

DOIURL[本文引用: 1]摘要

In this work, a coupled electromechanical peridynamics formulation is presented which is used to study the electrical and piezoresistive response of a carbon nanotube (CNT) reinforced polymer nanocomposite material. CNT nanocomposites are multiscale materials which have unique piezoresistive properties arising from mechanisms operating from the nanoscale to the macroscale. The origin of piezoresistivity in CNT nanocomposites is a nanoscale phenomenon known as electron hopping or the electrical tunneling effect which allows an electric current to flow between neighboring CNTs even when not in contact, thereby forming a conductive network. A nanoscale representative volume element of a CNT bundle is chosen, i.e. a local region of high CNT volume fraction within the polymer matrix, wherein coupled electromechanical peridynamic equations are solved to evaluate the effective electrical and piezoresistive properties. The peridynamics formulation is used to introduce electron hopping in a unique way, through electron hopping bonds which have a horizon distance and conductivity dictated by the appropriate physics operating at the nanoscale. The effective electromechanical response depends on parameters such as CNT volume fraction, properties of the polymer matrix between CNTs and applied strain which are investigated in detail. Both quasistatic and dynamic loading conditions are considered where the effective electromechanical response is found to depend on variations in the local conductivity of intertube regions.
[79] Prakash N , Seidel G D . 2017 .

Computational electromechanical peridynamics modeling of strain and damage sensing in nanocomposite bonded explosive materials (ncbx)

. Engineering Fracture Mechanics, 177 : 180 - 202 .

DOIURL[本文引用: 2]摘要

Polymer bonded explosives can sustain microstructural damage due to accidental impact, which may reduce their operational reliability or even cause unwanted ignition leading to detonation of the explosive. Therefore a nanocomposite piezoresistivity based sensing solution is discussed here that employs a carbon nanotube based nanocomposite binder in the explosive material by which in situ... [Show full abstract]
[80] Read D T , Tewary V K , Gerstle W H . 2011 .

Modeling electromigration using the peridynamics approach

. In Electromigration in Thin Films and Electronic Devices, 45 - 69 .

DOIURL[本文引用: 1]摘要

This chapter presents a summary of the information and reasoning needed to justify learning about peridynamics for the purpose of analyzing electromigration and provides guidance for the development of a complete peridynamics analysis. The additions needed to convert the original peridynamics model as developed for mechanics problems to a multiphysics model capable of treating electromigration are reviewed. Experimental data on void drift by electromigration are introduced to provide a specific target for a demonstration of the peridynamical approach. Model results for the basic phenomena of this experiment are presented. The peridynamics approach appears capable of simultaneously accommodating both constitutive laws and explicit treatment of multibody interactions, for handling different aspects of the behavior of the material system to be modeled.
[81] Roy P , Roy D . 2016 .

A peridynamic approach to flexoelectricity

. arXiv preprint arXiv: 1603 . 03894 .

URL[本文引用: 1]摘要

A flexoelectric peridynamic (PD) theory is proposed. Using the PD framework, the formulation introduces, perhaps for the first time, a nanoscale flexoelectric coupling that entails non-uniform strain in centrosymmetric dielectrics. This potentially enables PD modeling of a large class of phenomena in solid dielectrics involving cracks, discontinuities etc. wherein large strain gradients are present and the classical electromechanical theory based on partial differential equations do not directly apply. Derived from Hamilton's principle, PD electromechanical equations are shown to satisfy the global balance requirements. Linear PD constitutive equations reflect the electromechanical coupling effect, with the mechanical force state affected by the polarization state and the electrical force state in turn by the displacement state. An analytical solution of the PD electromechanical equations in the integral form is presented for the static case when a point mechanical force and a point electric force act in a three dimensional infinite solid dielectric. A parametric study on how the different length scales influence the response is also undertaken.
[82] Silling S A . 2000 .

Reformulation of elasticity theory for discontinuities and long-range forces

. Journal of the Mechanics and Physics of Solids, 48 : 175 - 209 .

DOIURL[本文引用: 3]摘要

Some materials may naturally form discontinuities such as cracks as a result of deformation. As an aid to the modeling of such materials, a new framework for the basic equations of continuum mechanics, called the ‘peridynamic’ formulation, is proposed. The propagation of linear stress waves in the new theory is discussed, and wave dispersion relations are derived. Material stability and its connection with wave propagation is investigated. It is demonstrated by an example that the reformulated approach permits the solution of fracture problems using the same equations either on or off the crack surface or crack tip. This is an advantage for modeling problems in which the location of a crack is not known in advance.
[83] Silling S A , Askari E . 2005 .

A meshfree method based on the peridynamic model of solid mechanics

. Computers & Structures, 83 : 1526 - 1535 .

DOIURL[本文引用: 2]摘要

An alternative theory of solid mechanics, known as the peridynamic theory, formulates problems in terms of integral equations rather than partial differential equations. This theory assumes that particles in a continuum interact with each other across a finite distance, as in molecular dynamics. Damage is incorporated in the theory at the level of these two-particle interactions, so localization and fracture occur as a natural outgrowth of the equation of motion and constitutive models. A numerical method for solving dynamic problems within the peridynamic theory is described. Accuracy and numerical stability are discussed. Examples illustrate the properties of the method for modeling brittle dynamic crack growth. [All rights reserved Elsevier]
[84] Silling S A , Epton M , Weckner O , Xu J F , Askari E . 2007 .

Peridynamic States and Constitutive Modeling

. Journal of Elasticity, 88 : 151 - 184 .

DOIURL[本文引用: 4]摘要

A generalization of the original peridynamic framework for solid mechanics is proposed. This generalization permits the response of a material at a point to depend collectively on the deformation of all bonds connected to the point. This extends the types of material response that can be reproduced by peridynamic theory to include an explicit dependence on such collectively determined quantities as volume change or shear angle. To accomplish this generalization, a mathematical object called a deformation state is defined, a function that maps any bond onto its image under the deformation. A similar object called a force state is defined, which contains the forces within bonds of all lengths and orientation. The relation between the deformation state and force state is the constitutive model for the material. In addition to providing a more general capability for reproducing material response, the new framework provides a means to incorporate a constitutive model from the conventional theory of solid mechanics directly into a peridynamic model. It also allows the condition of plastic incompressibility to be enforced in a peridynamic material model for permanent deformation analogous to conventional plasticity theory.
[85] Silling S A , Lehoucq R B . 2010 .

Peridynamic theory of solid mechanics

. Advances in Applied Mechanics, 44 : 73 - 168 .

DOIURL[本文引用: 1]

[86] Turner D Z . 2013 .

A non-local model for fluid-structure interaction with applications in hydraulic fracturing

. International Journal for Computational Methods in Engineering Science and Mechanics, 14 : 391 - 400 .

DOIURL[本文引用: 1]摘要

Modeling important engineering problems related to flow-induced damage (in the context of hydraulic fracturing among others) depends critically on characterizing the interaction of porous media and interstitial fluid flow. This work presents a new formulation for incorporating the effects of pore pressure in a non-local representation of solid mechanics. The result is a framework for modeling fluid-structure interaction problems with the discontinuity capturing advantages of an integral-based formulation. A number of numerical examples are used to show that the proposed formulation can be applied to measure the effect of leak-off during hydraulic fracturing as well as modeling consolidation of fluid-saturated rock and surface subsidence caused by fluid extraction from a geologic reservoir. The formulation incorporates the effect of pore pressure in the constitutive description of the porous material in a way that is appropriate for nonlinear materials, easily implemented in existing codes, straightforward in its evaluation (no history dependence), and justifiable from first principles. A mixture theory approach is used (deviating only slightly where necessary) to motivate an alteration to the peridynamic pressure term based on the fluid pore pressure. The resulting formulation has a number of similarities to the effective stress principle developed by Terzaghi and Biot and close correspondence is shown between the proposed method and the classical effective stress principle.
[87] Wang H L , Oterkus E , Oterkus S . 2018 .

Predicting fracture evolution during lithiation process using peridynamics

. Engineering Fracture Mechanics, 192 : 176 - 191 .

DOIURL[本文引用: 2]摘要

Silicon is regarded as one of the most promising anode materials for lithium-ion batteries due to its large electric capacity. However, silicon experiences large volumetric change during battery cycling which can lead to fracture and failure of lithium-ion batteries. The lithium concentration and anode material phase change have direct influence on hydrostatic stress and damage evolution. High pressure gradient around crack tips causes mass flux of lithium ions which increases the lithium-ion concentration in these regions. Therefore, it is essential to describe the physics of the problem by solving fully coupled mechanical-diffusion equations. In this study, these equations are solved using peridynamics in conjunction with newly introduced peridynamic differential operator concept used to convert partial differential equation into peridynamic form for the diffusion equation. After validating the developed framework, the capability of the current approach is demonstrated by considering a thin electrode plate with multiple pre-existing cracks oriented in different directions. It is shown that peridynamics can successfully predict the crack propagation process during the lithiation process.
[88] Wang L J , Xu J F , Wang J X . 2016 .

The Green's functions for peridynamic non-local diffusion//Proceedings of the Royal Society A: Mathematical Physical and Engineering Sciences

, 472 : 20160185 .

[本文引用: 1]

[89] Wang L J , Xu J F , Wang J X . 2018 .

A peridynamic framework and simulation of non-Fourier and nonlocal heat conduction

. International Journal of Heat and Mass Transfer, 118 : 1284 - 1292 .

DOIURL[本文引用: 1]

[90] Wang Y T , Zhou X P , Kou M M . 2018 .

A coupled thermo-mechanical bond-based peridynamics for simulating thermal cracking in rocks

. International Journal of Fracture, 211: 13--42.

DOIURL摘要

A coupled thermo-mechanical bond-based peridynamical (TM-BB-PD) method is developed to simulate thermal cracking processes in rocks. The coupled thermo-mechanical model consists of two parts. In the...
[91] Wildman R A , Gazonas G A . 2015 .

A dynamic electro-thermo-mechanical model of dielectric breakdown in solids using peridynamics

. Journal of Mechanics of Materials and Structures, 10 : 613 - 630 .

DOIURL[本文引用: 1]

[92] Wildman R A , Gazonas G A . 2017 .

A multiphysics finite element and peridynamics model of dielectric breakdown

. US Army Research Laboratory Aberdeen Proving Ground United States.

[本文引用: 1]

[93] Xu F F , Gunzburger M , Burkardt J . 2016 .

A multiscale method for nonlocal mechanics and diffusion and for the approximation of discontinuous functions

. Computer Methods in Applied Mechanics and Engineering, 307 : 117 - 143 .

DOIURL[本文引用: 1]摘要

A multiscale implementation of hybrid continuous/discontinuous finite element discretizations of nonlocal models for mechanics and diffusion in two dimensions is developed. The implementation features adaptive mesh refinement based on the detection of defects and results in an abrupt transition between refined elements that contain defects and unrefined elements free of defects. An additional difficulty overcome in the implementation is the design of accurate quadrature rules for stiffness matrix construction that are valid for any combination of the grid size and horizon parameter, the latter being the extent of nonlocal interactions. As a result, the methodology developed can attain optimal accuracy at very modest additional costs relative to situations for which the solution is smooth. Portions of the methodology can also be used for the optimal approximation, by piecewise linear polynomials, of given functions containing discontinuities. Several numerical examples are provided to illustrate the efficacy of the multiscale methodology.
[94] Xu Z P , Zhang G F , Chen Z G , Bobaru F . 2018 .

Elastic vortices and thermally-driven cracks in brittle materials with peridynamics

. International Journal of Fracture, 209 : 203 -- 222 .

DOIURL[本文引用: 2]摘要

Instabilities in thermally-driven crack growth in thin glass plates have been observed in experiments that slowly immerse a hot, pre-notched glass slide into a cold bath. We show that a nonlocal model
[95] Zhang H , Qiao P Z . 2018 .

An extended state-based peridynamic model for damage growth prediction of bimaterial structures under thermomechanical loading

. Engineering Fracture Mechanics, 189 : 81 -- 97 .

DOIURL[本文引用: 1]

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