Development of Hybrid Stress Measurement Technique Using Thermoelasticity and Photoelasticity and Its Application to Experimental Investigation of Fetting Problems.

本项目开发了一种基于热弹性和光弹性混合应用的全场应力分离测量新实验技术。利用所开发的技术进行了缺口和裂纹周围应力场测量的实验研究。所得结果总结如下：1。采用热弹性应力分析（TSA）和光弹性应力分析（PSA）相结合的应力分离测量技术。TSA法可测主应力之和，PSA法可测主应力方向和p*** **应力差。所有的应力分量都可以由莫尔应力圆来确定。研究了带圆孔加载板的应力分离问题。实验结果与边界元法分析结果进行了比较。实验结果表明，该方法得到的应力分量与边界元分析得到的应力分量基本一致。验证了所提出的应力分离混合测量的可行性。将所开发的混合应力分离测量技术应用于裂纹板在机械载荷作用下各应力分量的分布。实验结果与边界元法分析结果进行了比较。结果表明，中心裂纹和边缘裂纹周围的所有应力分量都可以准确地确定。根据实测应力分布计算应力强度因子和j积分。为了精确求出j积分，提出了近尖端不相容域积分法。结果表明，利用现有技术可以较准确地计算这些断裂力学参数。

The present project developed a new experimental technique of full-field stress separation measurement based on the hybrid use of thermoelasticity and photoelasticity. Several experimental investigations were carried out for measuring stress field around notches and cracks using the developed technique. The results obtained are summarized as follows.1. A hybrid measurement technique using both of thermoelastic stress analysis (TSA) and photoelastic stress analysis (PSA) developed for stress separation. The sum of principal stresses can be measured by TSA, while the difference of p***pal stresses and direction of principal stress can be measured by PSA. All of the stress components can be determined from the Mohr's stress circle.2. Stress separation of a loaded plate with a circular hole was investigated. The experimental results were compared with results of boundary element method analysis. It was found that the stress components experimentally obtained by the proposed technique coincided with those obtained by the boundary element analysis. Feasibility of the proposed hybrid measurement for stress separation is demonstrated.3. The developed hybrid stress separation measurement technique was applied for determining distribution of all individual stress components in cracked plates subjected to mechanical load. The experimental results were compared with results of boundary element method analysis. It was found that the all individual stress components around the center crack and the edge crack can be accurately determined. Stress intensity factors and the J-integrals were calculated from the measured stress distribution. For the accurate evaluation of J-integral, near tip exclusive domain integral method was newly proposed. It was found that these fracture mechanics parameters can be evaluated with good accuracies by the present techniques.