【摘要】 根据压痕法测量原理,建立了有限元分析模型,构造了残余应力范围σres/σy为-0.7~+0.7,分析了在不同载荷下压痕位移量,压痕接触应力分布规律,建立了不同位置处残余应力应变标定关系,在测试中根据不同位置处所得的应变量,代入到相应的标定关系式,计算得出残余应力。研究结果表明:残余拉、压应力程度大,压痕等效应力值大,弹塑性边界c宽。残余压应力程度越大,抗变形能力大,变形量小,接触应力分布范围窄;反之成立。在一定条件下根据所标定的残余应力应变关系所计算得到残余应力,与预先设定应力其吻合程度较高,说明标定关系可行;但也存在一定的偏差,在L=3mm处最大偏差范围在1%~31%。因此,合理的测试位置和测试技术的进一步研究对于提高残余应力测试精度尤为重要。更多还原

【Abstract】 The finite element analysis model with varying ratio of residual stress to yield stress σres/σy,was created to analyze the influence of residual stress on the indentation deformaion and indentation stress distributiom under different loads.It is shown that indentation equivalent stress increases and the elastic-plastic boundary c broadens as the residual stress increases.The indentation deformation,such as indentation depth,contact radius,and contact stress field distribution decrease with the compression residual stress,and vice versa.And an expression was obtained by quadratic polynomial fitting method to describe σres/σyand strain ε at different position under different loads.From experiment,strain value was measured, the residual stress was calculated by the established expression.The results show although the values from indentation testing are in good agreement with that given pre-stress,some difference exists at different measuring distance.The larger deviation ranges from 1% to 31% at measuring distance L=3mm.So measuring distance should be chosen reasonably,measuring technology should be further studied to improve testing accuracy.更多还原