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1、实验模态分析方法与应用概论报告人:姜节胜西北工业大学振动工程研究所IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China1/94姜节胜•Mob.13991123703•jiangjs@nwpu.edu.cnIVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20122/94张永强•Mob.13921730788•E-mailzh
2、angyqnwpu@163.comzyq@js-test.comIVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20123/94什么是振动模态?它有什么重要性?理论上的定义与意义实模态和复模态试验中获得模态的基本思路重要性模态试验方法新进展怎么从测试获取模态应变模态法SIMO捶击法小波(包)分析MIMO方法基本原理多参考点模态测试方法和PolyMax方法常用模态试验方法介绍参数识别的神经网络方法频域法环境激励下的模态测试
3、(不测力法)时域法工程应用实例IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20124/94什么是振动模态?它有什么重要性?理论上的定义与意义振动方程(从单自由度到多自由度)模态叠加法模态参数定义及其意义IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.2012振动方程5/94单自由度系统f(t)mx(t)
4、ck单自由度运动微分方程式为:mxcxkxfm、c、k分别为结构的质量、阻尼和刚度x、x、x分别为结构的加速度、速度和位移f为结构的外激励IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20126/94多自由度系统多自由度运动微分方程式为:Mx(t)Cx(t)Kx(t)f(t)幅度1+2xt加速度向量M=质量矩阵xt速度向量C=阻尼矩阵21K=刚度矩阵xt位移向量
5、频率ft外激励向量d+d12相位频率21md11+2IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20127/94时域方程:Mxt()Cxt()Kxt()ft()2Laplace域方程:(sMsCKXs)()Fs()特征值分析->系统极点和特征向量*2系统极点->共振频率和阻尼值k,1kkkjkk特征值向量->振型变换向量到模态空间f(t)f(t)fn(t)12kk1k2n
6、+1m1m2mngroundgroundcc2cn+11x(t)x(t)xn(t)12IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.2012模态叠加法8/94•令,,,代入振动方程,并对角化,第r阶模态贡献因子IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.20129/94qq1122++=…++q
7、33q44IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.2012模态参数定义及其意义10/94•模态频率、模态向量、模态质量、模态刚度、模态阻尼等总称为模态参数。阶数频率110.220263.6233177.084344.85IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniversity,China01.04.201211/94所有的模态都
8、可以通过以下几个参数来刻画:1.固有频率4.模态质量2.模态阻尼5.模态刚度3.模态形状IVEInstituteofVibrationEngineering,NorthwesternPolytechnicalUniver