选择不同应变花对主应力测试结果的影响

Effect on Measurement Results of Principal Stress by Selecting Different Strain Rosettes

为精确得到应力梯度较大点的应力状态,对5种应变片黏贴方案(即45°-3直角应变花、60°-3等角形应变花、120°-3Y形应变花、45°-4扇形应变花及多次黏贴单轴应变片)分别进行了研究,求解出待测点位的应力状态。利用ANSYS对构件上同一点的应力状态进行数值计算,并将实测值与数值计算结果进行对比与误差分析。结果表明,不同种类应变花布片方案测试结果存在差异,采用多次黏贴单轴应变片方案的测量结果更为准确。

When stress state of dangerous point of structure surface is measured with resistance strain measurement technique, the selection of strain rosette is of great importance. To measure stress state of point with larger stress gradient, five different strain rosette schemes, i. e. 45°-3 rectangular rosette, 60°-3 equiangular rosette, 120°-3Y rosette, 45°-4 sector rosette and multiple uniaxial strain gage adhesion, for convenience multiple SG is called later, were studied in detail to obtain stress state of point to be measured, respectively. Finite element analysis software ANSYS was used to analyze numerically stress state of the same point with strain rosette attached. The difierences as well as relative errors between different strain rosette schemes and numerical results were analyzed. We concluded that differences exist by using different strain rosette scheme and the multiple SG are more accurate than others.