Nonlinear random vibration of multiple-degree-of-freedom flexible structures
Received:December 04, 2007  
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DOI:10.7511/jslx20096004
KeyWord:flexible structures  geometrically nonlinear  equivalent nonlinear system  stochastic equivalent linearization  nonlinear random vibration  pseudo-excitation method
     
AuthorInstitution
何勇 浙江大学 结构工程研究所,杭州
金伟良 浙江大学 结构工程研究所,杭州
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Abstract:
      Stochastic equivalent linearization method has gained wide popularity because of its versatility in application to multi-degree-of-freedom nonlinear systems. It’s restricted in the random vibration analysis of flexible structures because of the implicit nonlinearity of the system. This paper presents a new method for the equivalent nonlinear system of flexible structures. Using this method, the implicit geometrically nonlinear system can be represented as an explicit equivalent nonlinear system. According to the modal analysis method, the geometrically nonlinear force is replaced by a high-order moment of modal coordinate. The multiple-degree-of-freedom (MDOF) physical system is translated into a modal system, which could be solved easily. Based on the equivalent nonlinear system, the nonlinear random vibration method is presented by using stochastic equivalent linearization technology. By using the pseudo-excitation method, the efficiency of the nonlinear random vibration method is increased obviously. The rapid calculation makes it possible to analyse the nonlinear random vibration of multiple-degree-of-freedom flexible structure. The validation shows that the method has reasonable precision and high efficiency and it could be used in the random vibration analysis of practical flexible structures.