钻孔法测量残余应力过程中钻孔附加应变的研究(Ⅱ)

Strains Induced by Hole Drilling Method for Residual Stresses Measurement

本文应用弹塑性理论研究了被测试样的屈服强度、应力场对钻孔法测量残余应力过程中钻孔附加应变的影响,使用简化的理论模型推导了低速旋转钻头钻孔产生附加应变的一般表达式.结果表明钻孔引入的附加应变与被测试样的原始残余应力状态有关,随应力水平增加而增大,在压应力减小到某一临界值σ时,钻孔附加应变为零。在 Ly12铝合金上的实验测量结果与理论结果一致。

The effects of yield strength,stress field on the drilling strain induced during residual stress measurements have been studied according to elastoplastic theory.A general formula for strain induced by low-speed drilling is derived according to simplified theoretic model.The results shown that the induced drilling strain is related to the original residual stress state in specimen.The induced drilling strain increases with an increment of stress,and reduces to zero as compressive stress decreases to a critical value σ_g.The experimental results measured on Ly12 aluminium alloy are coincident with the theoretic values.