有限元在粘弹性细棒动力学参数反演中的应用

粘弹性材料具有良好的阻尼性能，在工程振动与噪声处理上的应用非常广泛。利用粘弹性材料进行阻尼结构设计并预测其动力学特性，需要知道准确的动力学参数。回顾粘弹性材料动力学参数测试的经典方法，并着重介绍共振法测试技术。研究共振法测试中细棒的动力学响应与动力学参数间的关系，在此基础上，基于共振法测试数据和有限元仿真，提出一种反演粘弹性材料动力学参数的新方法。首先根据幅值比反演出损耗因子，再根据共振频率反演出储能模量。通过具体算例验证可知，反演得出的动力学参数的相对误差均在4 % 以内，该反演方法不仅结果收敛、准确可靠且反演速度快，为在连续频率范围内的动力学参数反演奠定基础。

Application of Finite Element Method to Inverse Analysis of Dynamic Parameters of Viscoelastic Slender Bars

Viscoelastic materials have been widely used in the noise and vibration control due to their high damping capability over wide temperature and frequency ranges. Design or selection of damping structure requires the knowledge of dynamic performance of the viscoelastic materials. Resonant bar technique is a classical method for measurement of viscoelastic material＇ s parameters. In this paper, an inverse analysis method for dynamic parameters estimation of viscoelastic slender bars was presented, in which the measured response of longitudinal vibration was asymptotically approached by the forward calculated response from the finite element computation. First of all, the loss factor was estimated according to the displacement magnitude ratio between the driven end and the free end of the bar. Then, the complex-modulus was estimated from the resonant frequency. The proposed inverse method was demonstrated valid and accurate by the experiment.