关键词: 喷丸, 应力松弛, 循环载荷, 数值仿真

Abstract:

The residual compressive stress field induced by shot peening can effectively improve the fatigue resistance of materials.However,the residual stress isn't constant,and its relaxation phenomenon caused by cyclic loading will reduce the effects of the shot peening on the fatigue resistance of materials.In order to conveniently and quickly achieve a residual stress field in a stable state,a numerical method to predict the residual stress relaxation under cyclic loading is proposed,and then it is used to achieve the stable residual stress fields of 7075 aluminum alloy specimens under different shot peening intensities and different load strengths.It is found that the simulation results accords well with the experimental results obtained through X-ray diffraction method.Thus,the correctness of the proposed numerical method is verified.In addition,the proposed numerical method is also applied to revealing the influences of the cycle numbers of loading,the stress ratios,the initial residual stress field and the plastic strains caused by the shot peening on the residual stress relaxation induced by the shot peening.

Key words: shot peening, stress relaxation, cyclic load, numerical simulation