“光弹性双轴应变计”在地应力测量中应用的可行性研究

FEASIBLE STUDY ON THE APPLICATION IN THE CRUSTAL STRESS MEASURE OF PHOTO ELASTIC BIAXIAL STRAIN GAUGE

摘要:

本文介绍了光弹性双轴应变计的原理、测量仪器和测量方法,并指出应变计中观测的最优点位置只与应变计材料的泊松比有关,最优点定位在给定的公差±0.25mm范围以内时,主应力差的可能误差为±4%。通过实验给出了该应变计的图象。

Abstract:

The authors present the principals, the measuring devices and method of a biaxial photoelastic strain gauge. It has been pointed out that the optimum position of measurement in the strain gauge depends upon the Poisson's ratio of the gauge material, only. Within a given positioning tolerance of ±0.25mm for the optimum measuring point, the maximum error of the measured differential principal stress is ±4%. Experiments show fringe patterns in the strain gauge with two clear and precisely perpendicular axes of symmetry, which indicate the directions of the principal strain. The biaxial photoelastic strain gauge made of proper materials with an outer diameter of 50mm, an inner diameter of 10mm, and a thickness of 4mm has a sensitivity of 6.45με. It provides a means of convenient, economic, and fast in-situ stress measurement.