散斑干涉微区应变测量术在腐蚀疲劳裂尖形变研究中的应用

AN APPLICATION OF SPI TECHNIQUE FOR STUDING STRAIN DISTRIBUTION AT CF CRACK TIP

建立了计算机控制自动化散斑干涉微区应变测量系统,介绍了工作原理及其在腐蚀疲劳裂尖形变行为研究中的应用,该方法可测定材料裂尖局部应变场。通过比较A537钢充氢前后裂尖应变场的变化与阳极溶解对纯Cu裂尖应变分布的改变、研究了腐蚀疲劳过程中裂尖材料的化学-力学效应,结果表明:充氢使裂尖应变减小。

A computerized digital speckle-interferometry(SPI) system has been set up todetermine the in-plane distribution of displacement and strain at crack tip of CF specimens.The effect of corrosion factors on plastic deformation at crack tip in CF process has been ex-amined by comparing the near-tip strain fields of steel A537 before and after hydrogen char-ging, and of pure Cu before and after applying an anodic current in 3.5% NaCl. The resultsshowed that the clasic finite element mathematical models were not suitable to describe thenear-tip deforamtion under the experimental conditions. Hydrogen charging made the cracktip plasticity decreased for steel A537 and the anodic dissolution enhanced the near-tipdeformation of pure Cu specimen.