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Research on Evaluation of Stress-Intensity Factor by Means of A-C Potential Drop Technique

交流电势降法评价应力强度因子的研究

基本信息

批准号：
02452097
负责人：
ABE Hiroyuki
金额：
$ 3.14万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

项目摘要

The research has been performed to develop a new method based on a-c potential drop technique for evaluating stress-intensity factor. The main results are summarized as follows:1. An increment of a-c potential difference caused by a load change was found to have a proportional relationship with an increment of the stress-intensity factor, K_I, for 2-D stationary surface crack.2. The quantity ROO<mu/sigma> was found to be a useful parameter in order to explain the loading effect, where sigma and mu are the conductivity and the permeability, respectively. The quantity ROO<mu/sigma> was denoted by gamma.3. Line impedance was introduced as a thin layer along the front of the semielliptical surface crack. The property of line impedance was determined by a frequency of the current and the change in gamma, which was expressed as a function of K_I by a 2-D experiment.4. A method for evaluating the unknown value of K_I for a 3-D surface crack was proposed by utilizing the line impedance model and the measurements of the change in potential drop.5. The availability of the present method was verified by an example, where the evaluated value of K_I was confirmed to agree well with the solutions of elastic analyses reported so far.6. The effect of geometrical relationship between current input and output probes and potential measuring probes on the measurement of the change in potential drop due to the change in load was examined.In 1992, the investigators and co-workers received the R.E. Peterson Award from the Society for Experimental Mechanics (U.S.A.) for the paper concerned with the present research program. Also in 1993, the investigators and a co-worker received the JSME Medal from the Japan Society of Mechanical Engineers.

本文研究了一种基于交流电位降技术的应力强度因子计算方法。主要研究结果如下：1.对于二维静止表面裂纹，由载荷变化引起的a-c电位差的增量与应力强度因子K_I的增量成正比关系.发现数量ROO<mu/sigma>是一个有用的参数，以便解释加载效应，其中sigma和mu分别是电导率和渗透率。量R 00 <mu/sigma>由γ 3表示。线阻抗被引入作为一个薄层沿沿着的半椭圆形表面裂纹的前端。线阻抗的特性由电流的频率和伽马的变化决定，通过二维实验将伽马的变化表示为K_I的函数.提出了一种利用线阻抗模型和电位降变化测量来估算三维表面裂纹的K_I未知值的方法.通过算例验证了本文方法的有效性，计算结果与已有弹性分析结果吻合较好.考察了电流输入和输出探头与电位测量探头之间的几何关系对测量负载变化引起的电位降变化的影响。1992年，研究人员和同事收到了RE美国实验力学学会彼得森奖本文是关于本研究项目的论文。同样在1993年，研究人员和一位同事获得了日本机械工程师协会颁发的JSME奖章。