Abstract:

Considering the flexibility of the foundation, using the evaluation parameters given by mechanical impedance to evaluate the isolation effect of the double-layer isolation system can not directly reflect the influence of the foundation’s stiffness on the isolation effect. This paper establishes the mechanical model of a flexible foundation double-layer isolation system and derives their physical parameter expressions from the definition of force transmissibility, insertion loss, vibration level difference, transfer power flow rate and insert power flow rate. These expressions can intuitively reflect the influence of the foundation’s stiffness on the isolation effect. Based on the example of a double-layer isolation system and from the influence of foundation’s stiffness values on the variation rule of force transmissibility, insertion loss, vibration level difference, transfer power flow rate and insert power flow rate with the excitation frequency, the conclusion is drawn that for the flexible foundation double-layer isolation system, the results of five kinds of evaluation parameters on the isolation effect are different according to the influence of the foundation’s stiffness. The results evaluated by the force transmissibility have a few differences, while the results evaluated by the insert loss and insert power flow rate have some differences, and the results evaluated by the vibration level difference and transfer power flow rate have big differences.

摘要：

在考虑基础柔性的情况下，用由机械阻抗给出的评价参数来评价双层隔振系统的隔振效果无法直观地反映基础的刚度对隔振效果的影响。本文建立柔性基础双层隔振系统力学模型，从力传递率、插入损失、振级落差、传递功率流率和插入功率流率五种隔振效果评价参数的定义推导并给出了它们的物理参数表达式，这些表达式可以直观地反映基础的刚度对隔振效果的影响。并以一个双层隔振系统的实例，分别就基础刚度取值对力传递率、插入损失、振级落差、传递功率流率和插入功率流率随激振频率变化的规律的影响，得出结论：对于柔性基础双层隔振系统，五种隔振效果评价参数对隔振效果的评价结果，受基础刚度的影响各有不相同，用力传递率评价的评价结果差异较小，用插入损失和插入功率流率评价的评价结果有一些差异，用振级落差和传递功率流率评价的评价结果差异较大。

关键词: 振动与波, 双层隔振系统, 柔性基础, 力传递率, 插入损失, 振级落差, 功率流