A、B标定值对盲孔法测定焊接残余应力精度的影响

本文利用盲孔应力松弛法测定焊接残余应力,发现标定值A、B不是与应力无关的常量。因此,在什么应力水平下标定出的A、B值才能用于计算残余应力,是影响测定精度的主要因素。本文还通过不同应力水平下的标定试验,提出这种测定残余应力的方法适用于残余应力大于1/4σs的场合。同时,标定A、B时加载应力应在(1/4～1/3)σs之间。在此范围内,加载应力越大,越有利于提高测定精度。

The Influence of Calibration Value A, B on the Measuring Accuracy of Residual Stresses by Hole-drilling Technique

It was found during residual stresses measurement by hole-drilling method that the calibration values A, B, parameters used for calculation of residual stresses, were not constants but dependent on the stress level at which A, B were to be determined. Thus, the selection of appropriate stress level for calibration will bring about a major influence on the accuracy of residual stress measurement. According to the calibration practice taken at various stress levels, it was recommended that the hole-drilling method can be used only for the situation that the residual stresses were greater than-as and the stress level of loading for calibrationof parameters A, B should be restricted between . Within thisrange of loading level, the greater the loading stress, the more favorable it was to the measuring accuracy.