孔挤压强化残余应力场的三维有限元模拟和实验研究

3D Finite Element Simulation and Experimental Test on Residual Stress Field by Hole Cold Expansion

运用有限元软件ANSYS建立了孔挤压强化残余应力场的三维有限元模型,模拟计算了不同厚度7050-T7451铝合金构件孔挤压强化的三维残余应力场分布。模拟结果表明,孔边残余应力沿厚度方向呈梯度分布,入口残余压应力最小,是易于产生裂纹的部位;入口残余压应力随构件厚度增加而增大,达到最大值后,随厚度增加而减小并逐渐趋于稳定值。同时,使用X射线衍射应力分析技术测量了实际试样的残余应力,结果表明,入口表面的残余压应力明显小于出口表面,并且实验测量值与有限元模拟值吻合较好。

The residual stress field of 7050-T7451 aluminum alloy with different thickness caused by hole cold expansion was simulated by FEM using ANSYS codes.The results show that the residual compressive stress of the hole edge exists grades across the thickness and the residual compressive value is smallest at the entrance,so the entrance becomes the most weakest region.With the increment of the thickness,the residual compressive stress at the entrance increases until reaching the maximum,then decreases and gradually tends to a stable value.The residual stress of the specimen was measured by the X-ray.The results show that residual stresses are obviously less compressive on the entry surface compared to the exit surface.The measurement was consistent with the FEM simulation.