疲劳裂纹扩展门槛值试验方法的探讨

本文就恒K控制的K梯度法疲劳裂纹扩展门槛值试验的实施方法。从硬件、软件及数值处理等方面进行了探讨,提出了用软、硬件滤波相结合的方法来减小裂纹长度测量值的波动,以提高试验的测量与控制精度。同时讨论了采用通用性较好的能描述全过程的疲劳裂纹扩展速率表达式进行外推估计疲劳门槛值的方法及其实际应用。本文也指出用王永廉提出的表达式将包含有低速扩展段数据点的试验数据进行曲线拟合外推,即能得到实用的门槛值数据,而试验时间比标准试验要少得多。

A Discussion on the Fatigue Crack Growth Rate Threshold Testing Method

This paper discusses the implement of the K gradient testing method by constant K control for fatigue crack growth rate threshold in hard ware, software and data processing, and puts forward that it has the advantages for crack length measuring to introduce both hardware filter and software filter which are important to the accurary of measuring and controlling. The paper also discusses the method of estimating fatigue crack growth rate threshold by inferring from a general fatigue crack growth rate expression which can de-seribe the whole testing curve as well as the application of the method with better unver-sality. The paper also points out that through some special treatment it is able for one to get usable data of fatigue crack growth rate threshold time if use the general fatigue crack growth rate expression proposed by Wang Yonglian from one's testing data and has e-nough data in low speed segment of propagation curve.