钻孔法中的残余应力场 Ⅱ.应用

Residual stress field in hole-drilling method-part Ⅱ:application

在修正的钻孔法测量残余应力的计算模型的基础上,推导了考虑硬化层时由释放应变表示的残余应力计算公式。以304不锈钢试件受单向均匀拉伸作用为例,将试件内的初始应力视为残余应力。钻孔测量了试件的释放应变,并分别按照不计硬化层和考虑硬化层两种方法计算了试件内的残余应力。同时采用16MnR钢试件在弯曲时的释放应变,分别采用这两种方法计算了试件内的残余应力。通过比较计算残余应力和真实残余应力(即给定的初始应力),计算了这两种方法的精度。此外,对轿车后桥的焊接残余应力进行了实测。结果表明,硬化层对残余应力的测量会产生明显的影响,从而进一步证明了将硬化层简化为异质圆环的计算模型的合理性和有效性。

Based on the modified computational model for the hole-drilling method to measure residual stresses,a new formula,considering the work-hardening layer,was developed to estimate the residual stress distribution by the relaxed strain.As an example,a 304 stainless steel specimen was submitted to a single uniform tension force,and the initial stress in the specimen was regarded as the residual stress.The relaxed strains were determined during hole drilling,and the residual stresses were introduced by two ways,in which the work-hardening layer was ignored and considered respectively.Using the relaxed strains published previously,the residual stresses in a bent 16MnR steel specimen were adopted by the same two ways as well.The accuracy of the two ways was presented by comparing the calculated residual stresses with the actual residual stresses,i.e.,the given initial stresses.Furthermore,the welding residual stresses were measured in a rear axle of the vehicle.The results indicate that the work-hardening layer has an obvious influence on distribution of the residual stress,and the modified computational model is logical and feasible.