基于轮廓法测试铝合金拉弯成形残余应力研究

Research on Measuring Residual Stresses in Aluminum Stretch-bending Workpiece by Using Contour Method

以2026-T3511铝合金T形结构件的拉弯成形件为研究对象,首先采用线切割将T形结构件分割成两块具有T形截面的试样,然后基于轮廓法测试应力原理应用激光位移传感器分别测试两个分割截面的轮廓变化,进而将两个截面的测量值拟合平均后与有限元模型结合以计算该试样的初始残余应力,从而获得该T形结构件的横截面法向应力并分析其分布特征。研究结果表明,基于轮廓法测得的应力分布与有限元仿真结果分布规律相近:峰值压应力为60MPa,峰值拉应力为40MPa;轮廓法在航空结构件应力测试中能够准确地获得其他测试方法无法获得的横截面完整的应力分布。

The aluminum alloy 2026-T3511 stretch-bending extrusion with T-section was measured by using contour method. The specimen was cut in two, then the contour of each cut surface was measured by using laser displacement sensor. The contour data was fit and combined with finite element model. The full map of residual stresses normal to the cross section was obtained. The finite element model of plastic forming was created to study about stresses distribution regularity. A distribution map of the specimen was got. The results show that the residual stresses from the contour method measuring is similar to the computer simulation of distribution regularity by finite element method. The peak value of compressive stress is 60MPa and the peak value of tensile stress is 40MPa. The contour method has advantage of getting full map of residual stresses distribution normal to the cross section over other methods.