振动试验夹具边界效应的动力学分析

振动试验夹具的边界效应是影响振动试验模拟精度的主要因素之一。忽略试验件与试验夹具之间的动力学作用,应用振动台的基础激励来模拟实际的振动环境,其结果的有效性依赖于工作状态的振动边界和试验状态的振动边界在多大程度上满足无限大阻抗输入模型假设。文章提出了一种分析夹具边界效应的有效方法,该方法来源于结构动力学分析的子结构方法,将包含夹具在内的试验系统的动力学特性表述为子结构动力学特征参数描述的标准特征值问题,通过特征频率与振型的比较,评价夹具的边界效应。数值模拟展示了分析过程,并验证了该方法的实用性。

Dynamic analysis on the boundary effects of fixture in vibration tests

Boundary effect of a fixture is the main factor that affects the precision in a vibration test. In environment engineering,the field vibration environment can be simulated by a base movement excited by a shaker under the assumption that the reaction between the test item and the fixture can be neglected. Therefore,the validity of the test depends on how far the test boundary can be considered as with infinite impedance connection. A new method is presented to analyze the boundary effects of the fixture based on dynamic substructure analysis. A numerical simulation validates the proposed method.