计入构件形变影响的超声波测量应力方法

根据弹塑性力学的基本原理,分析了材料在弹性应变范围内受单向应力情况下应变对超声波传播时间的影响,提出了经应变修正的超声波测量应力模型.采用基于超声波纵波回波信号的声时测定方法测试了立方体试样在无应力和有应力状态下的时间变化量,数据的重复测量误差仅为0.01%.实验证明了超声波测量应力模型的正确性和声时测定方法的可行性.通过对应变的修正,能够很好地反映出由应力引起波速变化所造成的时间变化量随应力变化的关系.

Ultrasonic measurement of stress considering strain effect

Based on the principle of elastic-plastic mechanics, the effect of strain on the measurement of ultrasonic transit time when the material was applied compression stress in the elastic area was analyzed. The model for measuring the stress using longitudinal waves was presented with the strain modified, and the transit time difference was obtained by a new method based on the echo signal of longitudinal wave. The transit time differences of the sample under stressed and unstressed state were measured, and the repeat error was less than 0.01%. The experimental results proved the correct of the model and the feasibility of the method estimating transit time difference. With the strain modified, the relationship between the transit time difference and stress can be more accurately manifested.