Abstract: Although viscoelastic structures have been widely used for vibration and noise reduction in the field of aerospace engineering, accurate calculation for dynamic parameters of viscoelastic structures remains difficult problem. Modal strain energy method and the corresponding modified methods have been always used for approximate calculations. On the basis of analysis of the priciples of existing modal strain energy methods and their correlations, a new modal strain energy method, whose correction factor varies with the amplitude of modal loss factor, is proposed for computing loss factor and natural frequency of viscoelastic structures. A four parameter prototype system, which is equivalent to beams and plates with constrained layer damping, and a new high damping spacecraft isolator are taken as example to verify accuracy of the proposed method by comparisons.

Key words: vibration and wave, viscoelastic, modal strain energy, loss factor, natural frequency

摘要： 粘弹结构在噪声与振动控制领域已得到广泛应用，然而准确地计算粘弹结构的动力学参数一直存在困难，模态应变能法及其修正方法常用作近似计算。在分析模态应变能方法和已有修正方法的原理及其相互关系的基础上，提出一种基于损耗因子幅值的新模态应变能方法，用于计算粘弹结构的损耗因子与固有频率。新方法的修正因子随粘弹结构对应模态阶次损耗因子幅值变化。取可等价为粘弹性夹层梁/板的四参数原型系统和新型高阻尼航天载荷隔振器为算例，通过与已有方法的对比分析了新方法的准确性。

关键词: 振动与波, 粘弹性, 模态应变能, 损耗因子, 固有频率