改进线弹性位移不连续模型和结构面弹性模量动力法测试

Improved linear elastic model of discontinuous displacement and dynamic measurement of interface elastic modulus

线弹性位移不连续模型难以准确描述应力波穿过厚度较大的宏观结构面的传播过程,对结构面透射侧的位移分量和应力分量进行多次泰勒展开,建立改进线弹性位移不连续模型,运用原模型和改进模型测试结构面弹性模量,研究阻抗比和结构面厚度对测试误差的影响,研究结果表明:当阻抗比较小时,应选择改进模型,基于反射波的波形差异测试结构面弹性模量;当阻抗比较大时,应选择原模型,基于透射波的波形差异测试结构面弹性模量;数值模拟得到测点振动波形,分析结构面厚度对测试偏差的影响,随结构面厚度增加,基于改进模型反射波波形差异的测试偏差减小,基于原模型透射波波形差异的测试偏差增加,现场试验与数值模拟的结果是一致的。

The propagation process of stress wave across the macro interfaces with larger thickness is difficult to be described using the linear elastic model of discontinuous displacement. The linear elastic model of discontinuous displacement was improved by adopting the multistage Taylor expansion of displacement component and stress component on the side of interface transmission. The elastic modulus of the interface was calculated using the customary and improved models respectively. The effect of impedance ratio and interface thickness on the test error was analyzed. The elastic modulus of the interface should be measured using the customary model based on the waveform difference of transmission wave when the impedance ratio was larger. The effect of interface thickness on the test deviation was analyzed using the vibration waveform of measuring points through numerical calculation. The test deviation,based on the reflection waveform difference adopting the improved model,decreased with the increase of the interface thickness. However,the test deviation based on the transmission waveform difference adopting the customary model increased with the increase of the interface thickness. The results of the field test and the numerical simulation were consistent with each other.