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基于多次附加质量模态试验的动力学模型修改
引用本文:王轲.基于多次附加质量模态试验的动力学模型修改[J].南京航空航天大学学报,2010,42(2).
作者姓名:王轲
作者单位:南京航空航天大学振动工程研究所,南京,210016
摘    要:用增加附加质量的模态试验修正结构动力学有限元模型是一种新颖的精确建模方法,但当测试模态数目较少时,由于识别方程中未知数数目大于方程数,计算精度会很差,影响了该项技术的实际应用.本文提出了一种用多次改变附加质量的多次模态试验数据来修正有限元刚度、质量矩阵的改进方法.该方法可增加参数识别方程个教,从而能有效地将参数识别欠定方程组变为超定方程组,使矩阵参数修正的准确性有效提高.文中通过两个例子具体研究了附加质量的模态试验次数与刚度、质量阵元素的修正精度及模型修改后模态计算精度的关系,表明该方法可行且有效.

关 键 词:建模  有限元  结构动力学  模型修正  模态试验

Dynamics Model Updating Based on Repeated Modal Testes with Added Known Masses
Abstract:Updating the structure FEM by the modal tests with added masses on the structure is a kind of new method. However, if the number of the tested modes is not sufficient, the calculating precision is not ideal because the number of unknown variables is more than that of the equations. This paper presents an improved method for measuring frequencies and mode shapes by repeatedly adding known masses to the structure to recognize and update the stiffness and the mass matrix. Because the recognition equations are increased, the under-determined equation will become the super-determined equation. Thus, the precision of the variables updated in these matrixes can be improved. Through two examples, the relationship is studied among the times of the modal tests with added masses and the precision of one stiffness matrix elements, mass matrix elements and the modes calculated. The result shows the feasibility and the validity of the method.
Keywords:building model  finite element  structural dynamics  model updating  modal test
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