悬臂弯曲加载表面裂纹长度与施力点位移的相关性研究

在悬臂弯曲加载方式下,采用五件带缺口光滑板状试样,通过循环载荷控制模式,研究了表面裂纹长度2c与试样施力点位移的相关性,结果表明:表面裂纹长度与施力点位移的谷值无相关性,但与施力点位移的峰值DP具有明显的相关性,即在表面裂纹扩展初期,DP几乎不发生变化,但随着表面裂纹的进一步扩展,DP开始增加,在表面裂纹扩展的后期,DP显著增加;在表面裂纹扩展的中后期,2c与DP满足递增多项式关系。根据2c与DP的函数关系,可为实现复杂环境条件下表面裂纹长度的自动化测量提供依据。

Study on Correlation between Surface Crack Length and Displacement of Loaded Point under Cantilever Bending Loading

Under cantilever bending loading,pertinence of surface crack length 2c to displacement of loaded point of the specimen was investigated,which was controlled by cyclic load with five notched smooth plate specimens. The results showed that there was no correlation between 2c and displacement valley-value of loaded point,but the correlation between 2c and displacement peak-value DPof loaded point is very obvious. During the original stage of surface crack propagation,DPkeeps nearly a constant and with further propagation of surface crack,DPbegins to increase and at the last stage of surface crack propagation, DPincreases obviously. At the median and last stage,2c and DPsatisfies a relation of polynomial increased by degrees. The function relation of 2c and DPwould provide reference for measuring surface crack length automatically under the conditions of complicated circumstance.