预拉伸铝合金厚板内部残余应力分布的测试方法

Measurement of Residual Stress Distribution in Pre-stretched Thick Aluminum Plate

根据弹性力学理论,针对铝板内部拉、压应力分布所产生的两种不同应变情况,推导出适应不同应变情况的改进剥层应变法.为验证该方法的准确性,通过有限元的方法对试件施加已知的初始内应力,运用生死单元技术模拟材料的去除,将得到的应变代入利用推导公式设计的VB数据处理系统中求出剥层深度应力.将求得的应力与初始已知的应力相比较,发现两者能很好地吻合,说明该方法可以用于预拉伸铝合金厚板内部残余应力的测量.

Based on the theory of elastic mechanics, the improved formulae of strain layering-peeling are deduced to adapt for the two strains, i.e., the tensile and compressive strains due to relevant stress distributions in pre-stretched thick aluminum plate. To verify the exactness of the method, the known initial internal stresses are applied to specimen by FEM, and the process of layering peeled material is simulated using the Live and Death technique to solve the deep layer stress by way of substituting the strains thus obtained into the VB data processing system based on the deduced formulae. Comparing the solved stresses with known initial stresses, it is found that both coincide well with each other. The result reveals that the method proposed can be used to measure the residual stresses in pre-stretched thick aluminum plate.