铝合金预拉伸板残余应力的超声测量

摘要

The relationship between velocity of ultrasonic critically refracted longitudinal (LCR ) wave propagating along different angles with respect to the stress direction and stress was studied in this paper.Besides, the residual stress in pre-stretched aluminum alloy plate was measured by using this relation.Finally,the result of stress measurement by using this method was compared to that of using hole drilling method.The experimental results show that velocity of LCR wave propagating parallel to the stress orientation decreases and velocity of LCR wave propagating perpendicular to the stress direction has hardly changes with the gradually increasing applied stress,therefore LCR wave is only sensitive to stress component along its propagation direction and stress component at specific direction can be measured by using LCR wave.The results of stress measurement by using ultrasonic was verified by using hole drilling method and the result shows that the results of measurement using those two methods have a relatively good consistency in the trend of stress distribution.The difference of the absolute value of residual stress by using those two methods is caused by the difference of their measuring range.%探讨了与应力方向成不同角度传播的超声临界折射纵波速度与应力的关系，并利用这一关系对铝合金预拉伸板的残余应力进行了测量，最后对此方法的应力测量结果与钻孔法的测量结果进行了对比。结果表明：随应力增加，沿平行于应力方向传播的临界折射纵波速度减小，而沿垂直于应力方向传播的临界折射纵波速度变化不大，因此临界折射纵波仅对沿其传播方向上的应力分量敏感，可利用其测量特定方向上的应力分量。利用钻孔法对超声应力测量结果进行了验证，得出二者的测量结果在应力分布趋势上具有较好的一致性，两种方法获得的绝对残余应力值的差异是由于其测量范围不同所造成的。