Abstract:The vibration control of linear boring bar system attached with linear dynamic vibration absorber and nonlinear energy sink under external harmonic excitation is studied. By ignoring the nonlinear factors in the boring bar system, the three degree of freedom motion equation of the boring bar system attached with linear dynamic vibration absorber and nonlinear energy sink is established, and the forced vibration of the boring bar system with combined dynamic vibration absorber is studied. The approximate analytical solution of boring bar system with combined dynamic vibration absorber is obtained by means of averaging method. The accuracy of the approximate analytical solution is verified by comparing with the numerical solution, and they are in good agreement with each other. By using the approximate analytical solution, the effects of linear dynamic vibration absorber and nonlinear energy sink parameters on the vibration suppression performance of boring bar are analyzed in detail. Based on the analysis of the influence law of the combined dynamic vibration absorber on linear boring bar system, the parameters of the combined dynamic vibration absorber with given mass are optimized, in which the linear dynamic vibration absorber parameters are optimized by using the approximate analytical solution of H _∞optimization method, and the damping of nonlinear energy sink is optimized by the approximate analytical solution of the system. The analysis results show that the combination of linear dynamic vibration absorber and nonlinear energy sink can effectively suppress the vibration of linear boring bar system, moreover, the linear boring bar system can obtain better vibration attenuation effect by using the combined dynamic vibration absorber with optimized parameters. By adding nonlinear energy sink can not only improve the vibration suppression effect of linear dynamic vibration absorber, but also improve the robustness of vibration control system. The analysis results can provide a reference for the design of built-in damping boring bar.