疲劳裂纹扩展门槛值测试技术

Measuring and testing techniques of fatigue crack growth threshold

针对裂纹扩展门槛值测量技术中存在的不足,应用数字化测量技术采集试样测点位移与试验载荷,采用柔度法计算裂纹长度,由测点位移波形的峰值记录循环次数,多线程软件设计实现试验控制和数据采集、监视与处理一体化,从而保证测试结果的准确性.根据不同载荷比下40CrNiMo钢疲劳裂纹扩展门槛值成组试验的结果,验证了上述测试技术的可靠性与可行性.

In view of insufficiency in crack growth threshold measurement technology, the survey- point displacement of specimen and test-load are collected through digital measurement technolo- gy, and the crack size is calculated through the compliance method, the cycle index is recorded according to the wave crest of survey-point displacement. Besides, the integrated objective Of test control, data collection, monitoring and processing are implemented by the multi-thread software. The results of the fatigue crack growth thresholds of steel 40CrNiMo, which are obtained from group test method under different load-ratio, prove the reliability and feasibility of measuring and testing techniques.