关键词：
Modal analysis;reanalysis;large complex structure;the pseudo random number initialization;ICII;topology optimization
摘要：
Modal analysis is widely used to investigate the dynamic characteristics of large and complex structures. For finite element models, iterative solvers are needed to precisely calculate eigenpairs or frequency and vibration mode. However, in cases such as large-scale analysis or reanalysis studies, or optimization design of a huge structure, computational cost may become too time consuming. This paper focuses on the quick structural modal analysis based on the reanalysis technique for large complex structures. Based on the stiffness and mass matrix of the analytical structures, a high precision and efficiency eigensolution is generated by the proposed modal analysis method (the Pseudo Random Independent and Coupling Inverse Iteration (PRICII) method), which combines the pseudo random number initialization, ICII (Independent and Coupling Inverse Iteration) strategy with the double Rayleigh–Ritz analysis. By comparing with the Subspace iteration method, Lanczos method, etc. the large-scale numerical examples show that the actual computational savings of the proposed method are usually higher than 75% with sufficient precision. Also, its applications in topology optimization are greatly effective.
摘要：
A negative stiffness element is always employed to generate high-static-low-dynamic stiffness characteristic of the vibration isolator, reduce the resonance frequency of the isolator, and improve the vibration isolation performance under low and ultra-low frequency excitation. In this paper, a new compact negative stiffness permanent magnetic spring (NSPMS) that is composed of two axial-magnetized permanent magnetic rings is proposed. An analytical expression of magnetic negative stiffness of the NSPMS is deduced by using the Coulombian model. After analyzing the effect of air-gap width, air-gap position, height difference between the inner ring and outer ring on the negative stiffness characteristic, a design procedure is proposed to realize the negative stiffness characteristic with a global minimum linear component and uniformity stiffness near the equilibrium position. Finally, an experimental prototype is developed to validate the effectiveness of the NSPMS. The experimental results show that combining a vibration isolator with the NSPMS in parallel can lower the natural frequency and improve the isolation performance of the isolator.
关键词：
Boundary, Topology and type modifications;ICMO;Modal reanalysis;Rayleigh-Ritz analysis
摘要：
Eigenvalue problem is widely used to investigate the dynamic characteristics of large and complex structure. For finite element models, iterative solvers are needed to precisely calculate eigenvectors and eigenvalues. However, in cases such as large-scale reanalysis studies, or optimization design of huge structure, computational cost can quickly become too time consuming. This paper focus on the structural modal reanalysis for large and multiple modifications (including simultaneous boundary, topology and type modifications), which can greatly affect the eigen-modes of the modified structures. The proposed methods are based on the results from the modal analysis of the original structure, and the stiffness and mass matrix of the modified structures. A highly approximate eigensolution are generated by the proposed method, which is combined the newly added DOF (Degrees of Freedom) condensation, ICMO strategy (Independent and Coupling Mass Orthogonalization) with the Rayleigh-Ritz analysis. The numerical examples show that the proposed method is efficient with high precision even when large and multiple type modifications of the structural topology, boundary and type are made simultaneously. (C) 2015 Elsevier Ltd. All rights reserved.
作者机构：
[Jianjun He; Xiangzi Chen] School of Automobile and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410004, China
会议名称：
The 4th International Conference on Dynamics, Vibration and Control, ICDVC-2014(第四届国际动力学振动与控制会议)
会议时间：
2014-8-23
会议地点：
上海
会议主办单位：
中国力学学会;上海应用数学力学所
会议论文集名称：
The 4th International Conference on Dynamics, Vibration and Control, ICDVC-2014(第四届国际动力学振动与控制会议)论文集
摘要：
<正>In this paper,the problem of integrated topology optimization design of piezoelectric smart truss structure/control is studied.The simulation computations of simultaneous optimization for structure
关键词：
dynamic reanalysis;modification of structural topology;reduced model;Rayleigh-Ritz analysis
摘要：
The paper presents a new improved method for structural dynamic reanalysis with large change in structure topology possessing added degrees of freedom (DOF). The method，which is based on twice reduced model of original and topological structures, combines independent mass orthogonality and Rayleigh-Ritz analysis. Two numerical examples were used to show that the presented method can provide efficient and high quality approximation result for eigenvalues reanalysis when large modifications of the structural topology are made.
作者机构：
[何建军] School of Automobile and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China;[何建军; 姜节胜; 徐斌] Institute of Vibration Engineering, Northwestern Polytechnical University, Xi'an 710072, China
通讯机构：
School of Automobile and Mechanical Engineering, Changsha University of Science and Technology, China
