基于数值－解析法测量静压条件下阻尼材料动态力学参数

摘要

建立了一种测量静压条件下阻尼材料动态力学参数的数值－解析法。分别制作两种空腔半径不同的圆柱空腔覆盖层样品，测量两种样品在静压力下的复反射系数；采用有限元法仿真静压力下的空腔结构变形，在此基础上同样采用有限元法计算复反射系数。以实测复反射系数和计算复反射系数建立二元非线性方程组，利用牛顿迭代法求解方程组获得复弹性模量和复泊松比等黏弹性动态力学参数；对聚氨酯材料制作的样品进行复反射系数测量，分析了静压力对聚氨酯材料动态力学参数的影响规律。测量了某不同结构吸声覆盖层静压下的反射系数，并与采用实测材料参数计算的反射系数进行比较，验证了该方法的正确性。%For viscoelastic dynamic parameters measurement of damping materials under hydrostatic pressure,a hybrid numerical-analytical method was developed.Firstly,two different samples of sound absorption coatings containing cylindrical holes with two different radii were tested in order to obtain the two different measured complex reflection coefficients under hydrostatic pressure.Secondly,the complex reflection coefficients were calculated with FEM based on the structural deformation simulated with the FE method.Then,using the measured and the simulated complex reflection coefficients simultaneously,two nonlinear equations were established.Using Newton iteration method,the nonlinear equations were solved,the viscoelastic dynamic parameters including complex elastic modulus and complex Poisson's ratio were obtained.Then,two samples made with polyurethane were tested in a water-filled acoustic-pipe,and the effects of hydrostatic pressure on the viscoelastic dynamic parameters were analyzed and summarized.Finally,the reflection coefficient of another different sound absorption coating tested under hydrostatic pressure was measured and compared with the simulated reflection coefficient calculated with the measured viscoelastic dynamic parameters,the correctness of the proposed method was verified.