Effect of laser peening area on residual stress field in small-hole specimens

To investigate the effect of different laser peening area on the residual stress field in a hole specimen of 7075-T7451 aluminum alloy, the process of laser peening and residual stress distribution of the hole specimen were simulated by finite element analysis software ABAQUS. The results show that both the compressive stress of surface residual and the tensile stress of unshocked area increase as laser peening area becomes bigger,the tensile stress of unshocked area changes from 52MPa to 344MPa. The residual stress distribution along inner hole wall turns out to be worse with the increase of laser peening area, the value of the worst stress along the hole inner wall changes from the compressive stress 38MPa to the tensile stress 49MPa. Within a certain range of laser peening area, the increase of laser peening area enlarges surface compressive stress coverage and makes residual stress distribution of inner hole wall worse. For laser peening of a hole specimen, it is important to control laser peening area and the surface residual stress distribution along hole inner wall, in order to improve the fatigue resistance.