激光喷丸强化TC4钛合金疲劳性能的数值模拟研究

Numerical Study on Fatigue Property of TC4 Titanium Alloy by Laser Shock Peening

采用有限元软件ABAQUS和MSC.Fatigue为平台,对不同喷丸方式(单面、双面)、不同激光功率密度(5.66,7.08,8.49 GW/cm2)、以及不同喷丸路径(3、5、7排)下,对TC4钛合金单联中心孔试样激光喷丸过程进行数值模拟研究,分析不同工艺参数对TC4钛合金残余应力分布以及疲劳寿命的影响。结果表明:双面激光喷丸的效果远优于单面激光喷丸,双面喷丸后最大残余压应力值比单面喷丸后增加了29%。同时,双面激光喷丸后,上表面最大残余压应力值达-746 MPa,比下表面最大残余压应力值提高了21%。激光喷丸后试样表面残余压应力随着激光功率密度以及喷丸覆盖率的增大而增大,最后趋于饱和;不同喷丸覆盖率对深度方向上残余应力影响不大。模拟结果表明,激光喷丸强化诱导的残余压应力分布对TC4钛合金单联中心孔试样有较好的延寿作用。

The finite element analysis software ABAQUS and MSC.Fatigue were used to establish the model of laser peening（LP） and fatigue life of TC4 titanium alloy. The effect of shot peening way of single side and double sides as well as power density ranging from 5.66 GW/cm2 to 8.49 GW/cm2 , coverage rate ranging from 3 rows to 7 rows on residual stress field and fatigue life of TC4 titanium alloy subjected to LP were studied. The results show that the residual stress distribution of double sides is better than single side which result in a great increase of 29%, meanwhile, the maximum top surface residual stress reach -290 MPa after double sides subjected to LP which increase by 21% than bottom surface residual stress. The surface residual stress increase with power density and coverage rate, and finally reaches saturate state. The residual stress depth has little relation with the coverage rate.h can be concluded that the residual stress field induced by LP has a good inhibition effect on fatigue properties.