销钉接触对电位法测试精度影响的边界元分析

 用边界元法分析了销钉接触对3种电流输入方式下紧凑拉伸试样的电位函数影响。结果表明,销钉接触对电位测试精度有显著影响。试验中应首先考虑对俏钉孔进行绝缘。当不可能对销钉孔进行绝缘时,应对电位函数进行修正或变换电流输入位置。

ANALYSES ON EFFECT OF DOWEL CONTACT WITH HOLEON MEASURING ACCURACY OF ELECTRICAL POTENTIALMETHOD WITH BOUNDARY ELEMENT METHOD

It is well known that the accurate electrical potential function is one of the necessary conditions for guaranteeing the precision of measurement with electrical potential method (EPM). But up to now, there is no published report in the open literature on effect of dowel contact with hole on the measuring accuracy of EPM of compact tension specimen. The new contribution of this paper is that such an effect is studied with boundary element method. The author's analysis shows that the contact of dowel with hole has significant effect on the measuring accuracy of EPM. Firstly, it should be considered whether dowel can be insulated with hole or not. If dowel can be insulated with hole, the optimum measuring to input current. If dowel can not be insulated with hole, point C should be adopted as the place to input current. However, for the case of measuring small crack behaviour, probing sensitivity becomes the main problem, then point A should also be adopted as the place to input current, but the electrical potential function must be correctly modified to eliminate the error of measurement due to the effect of dowel contact with hole.