VIBRATIONAL CHARACTERISTICS OF HONEYCOMB SANDWICH CANTILEVER PLATE WITH CURVED-WALL CORE

As a kind of porous material, the honeycomb structure has the advantages of light weight, high strength, high stiffness, sound insulation, noise reduction, heat insulation and other excellent performance. Therefore, it is widely used in the field of transportation vehicles and aerospace etc. The traditional straight wall honeycomb is prone to stress concentration after loading, which will lead to crack failure and shorten the service life of the honeycombs. In order to solve this problem of honeycombs with straight walls, a honeycomb sandwich plate with circular arc core layer is designed in this paper. The equivalent parameters of honeycomb core are derived based on unit load method and the dynamic model of the curved-wall-core honeycomb sandwich plate is derived. The Chebyshev-Ritz method was used to solve the natural frequencies of honeycomb sandwich plate under cantilever boundaries, and the finite element method is used to compare. The errors of the first five natural frequencies are all within 5% from the two methods. The modes corresponding to each order of natural frequencies obtained from the finite element model are consistent with those obtained from the theoretical model. The curved honeycomb sandwich plate is prepared by 3D printing polylactic acid (PLA). The Young’s modulus of the printed PLA was measured by quasi-static tensile of the tensile specimen using a universal testing machine. The vibration test platform is built to do the sine sweep test, fixed frequency harmonic resides test and impact test. The comparison shows that the first five natural frequencies obtained from the vibration test of the 3D printing model verify the calculation results of the theoretical model and the finite element model. It is found that the curved-wall honeycomb core has a certain impact resistant performance in a specific frequency band. The obtained research results will provide theoretical support for the application of curved wall honeycombs in vibration and vibrational isolation.