基于比容测量对材料三维残余应力及其分布的测试分析

Measuring and Analysis of Three-dimensional Residual Stress and Its Distribution in Materials Based on Measurement of Specific Volume

目的判断比容差法是否可应用于材料内部残余应力分布状态的定量研究,旨在提供一种新的残余应力的测试方法。方法通过对材料非切应变时的弹性力学进行讨论,推导体积应变,得出残余应力的计算公式。应用比容差法对一种工业纯铝的残余应力状态进行定量测量与表征,并进行钻孔法的定量验证。在此基础上,应用比容差法对纯铝镦粗变形后的三维平均残余应力的分布进行了测量研究。结果比容差法对纯铝镦粗变形后的体积变化测量,可精确、定量表征材料的残余应力状态,与钻孔法实验结果相比,两者的误差在20%以内;镦粗变形后,残余压应力在坯料中心处取得最大值,且对称于中心沿高度方向逐渐减小,呈对称递减分布。结论比容差法可用于材料三维残余应力分布的研究,为残余应力分布规律,提供了一种新的有效且精确的测试方法,具有实际应用的价值。

The paper aims to estimate whether the differential specific volume analysis method can be appllecl to quanuta- tive research on residual stress distribution in material to provide a new measurement method for residual stress. Though dis- cussing the elasticity of non-shear strain in material, the equation describing residual stress was obtained by the deriving volume variation. Thus, the differential specific volume analysis method was taken for measuring and characterizing the residual stress state in pure aluminum. Then, this new method was quantitatively validated by hole drilling method. On this basis, the distribu- tion of three-dimensional average residual stress in forged pure aluminum was investigated by the differential specific volume analysis method. The residual stress distribution on the three-dimensional surface of pure aluminum after forging can be accu- rately characterized by this new method. Compared with the experimental results of hole drilling method, the deviation between them was less than 20%. After forging, the maximum of residual compressive stress appeared at the center of billet, and that the value decreased gradually along the height. The residual compressive stress displayed a symmetrical decreasing distribution. Therefore, the differential specific volume analysis method can be applied to research the three-dimensional residual stress dis- tribution, which proposes a new analysis and test method for predicting the distribution law of residual stress. It has practical application value.