一种基于系统保形解耦的力源识别方法

基于模态分析法的力源时域识别方法中涉及利用模态矩阵将系统方程转化为非耦合形式,这仅对比例阻尼或经典阻尼系统才能实现。文章基于二阶系统保结构解耦方法建立了新的力源识别数学模型。首先利用Lancaster结构建立系统的解耦模型,并求得解耦变换;其次,利用解耦变换推导建立系统非耦合响应模型,并在微小时段内力源为线性变化的假设下,推导出具体的力源识别公式。最后,采用精细逐步积分方法,对模型进行解算,由结构动态响应反求力源的时间历程。数值实验不仅验证了所提方法可以提高识别精度,而且也验证了所提方法对非比例阻尼系统也是有效的,这也是文中方法的重点。

A load identification method based on decoupling of Lancaster structure

The way of the load identification in time domain which is based on the modal analysis that the system equation is transformed into a non-coupling form by modal matrix,is only applicable for the proportional damping or classical damping system.In this paper,based on structure-preserving decoupling method of second-order system,a new mathematical model of load identification was established.The system-decoupling model was established based on the Lancaster structure and the decoupling transformation was obtained;then,the model of uncoupled response system based on the decoupling transformation was established,and on the assumption of linear load identification in tiny-time,the formula of load identification was deduced;finally,the model was calculated based on high precision direct integration scheme,and the history of force identification was obtained by structural dynamic response.The experiments verify that the proposed method could improve the accuracy of recognition,and is effective for the non-proportional damping system.And it is the focus of the paper.