盲孔法测量高残余应力的可靠性与精确度

Reliability and precision of blind hole drilling method for determining high residual stresses

钻孔法测量残余应力的范围是应力不超过材料屈服极限的一半。但是在许多情况下,钻孔法是用于测量焊接残余应力,而该应力峰值往往接近材料的屈服极限。本文探讨了盲孔法测量高残余应力的可靠性与精确度。为了模拟工程应用中测量残余应力的实际过程,本文采用标定的方法,即在试验机保持一定载荷不变的条件下进行贴片与钻孔操作,测得释放应变值。试验结果表明,用测得释放应变值计算出的应力值与标定应力值吻合较好,最大绝对误差仅为21MPa。

The scope of the residual stresses determined by the hole drilling method should not exceed one half of the material's yield strength. But this method is used to determine welding residual stresses in many cases where the stress peaks are often near the material's yield strength. The reliability and precision of the blind hole drilling method for determining high residual stresses were searched in this paper. For simulating the real process of determining residual stresses in engineering application, the calibrating method was taken. The operations of bonding strain gage rosette and hole drilling ware taken under the loading condition and the relaxation strains were measured. The results of experiment show that the data calculated with ths measured relaxation strains are in good agreement with its calibrated stresses and the largest absolute deviation is 21 MPa.