TC17钛合金超声喷丸强化残余应力场分析

Residual Stress Field Analysis of TC17 Titanium Alloy by Ultrasonic Shot Peening

为探究TC17钛合金超声喷丸强化残余应力场分布状态,基于ABAQUS/Explicit建立了超声喷丸振动系统,结合仿真与试验结果分别探究了0.15 A与0.25 A喷丸强度下TC17钛合金试样的应力场、表面形貌和应变层分布状态。两种喷丸强度下,残余压应力最大值均处于次表面区域。在表面残余应力均值、次表面残余压应力最大值、残余应力层深度方面仿真数值与试验结果差异较小,整体偏差小于15%。随着喷丸强度增加,施密特因子集中分布范围有降低的趋势。0.25 A喷丸强度下应变层与残余压应力层深度分布相近,分别较0.15 A喷丸强度下的深度值提升57.1%与53.3%。高周疲劳结果表明,相比0.15 A喷丸强度,0.25 A喷丸强度下疲劳极限提高4.7%,两种喷丸强度下疲劳寿命均达到10^(7)次循环。残余压应力层深度在高载荷低循环下作用较小,在低载荷高循环下对裂纹萌生的抑制作用增加,较高的表面残余压应力及较深的残余压应力层深度对抑制残余拉应力引起的疲劳失效效果更显著。

In order to explore the distribution of residual stress field in TC17 titanium alloy with ultrasonic shot peening,an ultrasonic shot peening vibration system was established based on ABAQUS/Explicit.Combined with simulation and experiment,the stress field,surface morphology and strain layer distribution of TC17 titanium alloy with 0.15 A and 0.25 A shot peening intensities were investigated respectively.Under two shot peening intensities,the maximum value of compressive residual stress is all in the sub-surface region.There is a small difference between the value of simulation and the test in the mean value of residual stress on the surface,the maximum value of compressive residual stress on the sub-surface and the depth of residual stress layer,and the overall deviation is less than 15%.With the increase of shot peening intensity,the concentrated distribution of Schmid factor tends to decrease.Under shot peening intensity of 0.25 A,the depth distribution of strain layer and compressive residual stress layer is similar,increasing by 57.1% and 53.3% compared to 0.15 A respectively.High cycle fatigue results show that,compared with 0.15 A,0.25 A shot peening intensity fatigue limit increases by 4.7%,and the fatigue life under two kinds of shot peening intensities achieve 10^(7)cycles.The depth of compressive residual stress layer has little effect under high load and low cycle,and inhibition of crack initiation increases under low load and high cycle.Higher surface compressive residual stress and depth of compressive residual stress layer have more significant effects on restraining fatigue caused by tensive residual stress.