超声纵波法测试铝合金的内部应力

声各向同性的金属材料在应力作用下表现出声各向异性,这是用声弹性法分析材料内部应力的基础。用垂直于应力方向传播的超声纵波对LY11型铝合金进行测试。实验结果表明:材料在拉、压单轴应力作用下,超声纵波声速都发生了变化:声速随拉应力的增大而增大,随压应力的增大而减小;且声速相对变化率与应力呈线性关系,并拟合出相应的直线方程,直线斜率为铝合金纵波声弹性系数。通过实验提供了一种无损检测材料内部应力的方法。实验中用回振法测量声速,时间测试精确度可达10-11s,可精确测量声速的微小变化量。

Stress Measurement in Aluminum Alloy by Ultrasonic Longitudinal Waves

Acoustic anisotropy effect occurs when a isotropic metal is submitted to stress,which is the base of stress determination in material by acoustoelasticity.A test on LY11 aluminum alloy was given by ultraso-nic longitudinal waves vertical to the direction of uniaxial stress.The result is that the velocities of ultrasonic longitudinal waves have been changed under the uniaxial stress,and they increase with the enlargement of tensile stresses,decrease with the enlargement of the compressive stresses;and the re...