云纹干涉与钻孔法测量残余应力的实验方法与系统

An Experimental Method and System for Residual Stress Measurement with Moiré Interferometry and Hole Drilling

应变片钻孔法是工程中应用最广的残余应力测量方法之一.由于应变片只能得到其长度范围内的平均应变,测量误差比较大.本文提出用云纹干涉法测量的位移信息代替应变片测量的应变信息来确定残余应力,用有限元建立位移与残余应力之间的关系.基于以上理论,开发了一种可以进行现场残余应力测量的便携式云纹干涉钻孔系统,并用该仪器进行了铝合金激光焊接接头的残余应力测量,得到了焊缝中心残余应力值.

Strain gage hole drilling method is one of the most popular residual stress measurement methods. Because the strain data measured by gages are the average strains in the length of the gages, the measurement error is possiblly rather large. This paper proposes a method where displacement data measured by moiré interferometry instead of the strain information are used, and finite element method was used to establish the relationship between the displacement and the residual stress. Based on the above theory, a portable moiré interferometry and hole drilling system was designed. Residual stresses of a laser welded aluminium alloy were measured by using this system.