铝合金薄板自冲铆接疲劳寿命仿真与分析

Simulation and analysis on fatigue life of self-piercing riveting for aluminum alloy sheet

建立铝合金薄板自冲铆接结构的疲劳寿命预测模型。采用有限元软件ABAQUS和疲劳分析软件FE-SAFE,通过有限元仿真和数理统计多元正交回归实验,研究了表面粗糙度和残余应力对自冲铆接构件疲劳寿命的影响规律。拟合出自变量为表面粗糙度、残余应力、最大应力,因变量为疲劳寿命的函数关系式,得出疲劳寿命随表面粗糙度和残余应力的变化趋势。研究结果表明:表面粗糙度、残余应力、最大应力及两两交互作用对疲劳寿命的影响从大到小的顺序为:残余应力、表面粗糙度与残余应力的交互作用、表面粗糙度;最大应力为固定值且表面粗糙度不变的情况下,残余应力减小,疲劳寿命增大;残余应力不变的情况下表面粗糙度增大,疲劳寿命减小。疲劳实验结果与仿真结果的平均误差为9.74%,证明仿真结果可靠。

The fatigue life prediction model of self-piecing riveting structure for aluminum alloy sheet was established,and based on the finite element software ABAQUS and the fatigue analysis software FE-SAFE,the influence laws of surface roughness and residual stress on the fatigue life of self-piecing riveting components were studied by finite element simulation and mathematical statistics multivariate orthogonal regression experiment.Then,the function relation taking surface roughness,residual stress as independent variables and maximum stress and taking fatigue life as dependent variable was fitted,and the variation trend of fatigue life with surface roughness and residual stress was obtained.The results show that the order of influences of surface roughness,residual stress,the maximum stress and pairwise interaction on the fatigue life is residual stress、interaction of surface roughness and residual stress and surface roughness.When the maximum stress is fixed and the surface roughness is unchanged,the residual stress decreases and the fatigue life increases,and when the residual stress is unchanged,the surface roughness increases and the fatigue life decreases.Finally,the average error between fatigue experiment results and simulation results is 9.74%,which proves that the simulation results are reliable.