一种测量平面主应力的简便方法

A simple and convenient method about measurement of principal stresses in plane stress state

测量一点的主应力的电测实验是材料力学实验中的基本实验。在该实验中，为了测量构件表面一点的主应力大小及方向，通常采用3个1／4桥路，测量该点沿3个敏感栅方向的线应变，根据平面应变状态分析和广义胡克定律求得该点的主应力大小及方向。该文通过对构件表面一种常见应力状态的分析，提出了只用1个1／4桥路和1个1/2桥路便可测得该点主应力大小及方向的简便方法，从而简化了实验过程，提高了测量精度。

The experiment of measuring principle stresses at one point by the strain gauge method is a basic experiment in mechanics of materials. To determinate volumes and directions of the principle stresses, constantly three 1/4-bridges should be applied to measure normal strains along three sensitive grids. Based on the analysis of the plane stress state and generalized Hooke＇ s law, volumes and directions of the principle stresses at one point will be obtained. According to the analysis of a common stress state, a simple and convenient method is suggested, which only uses one 1/4 and one 1/2-bridges to measure volumes and directions of the principle stresses at one point. Thereby, the procedure of the experiment is simplified and the accuracy is increased.