A Research On Dynamic Reanalysis Methods Of Structure Type And Topological Modification

With the rapid development and continuous progress of engineering practice and finite element technology, the reanalysis issues in optimum structural design has become a research hot spot at present. Basing on the analysis result of initial structure, the reanalysis can make use of the coherence of original structure and modified structure and then gets an approximate result for modified structure with a higher precision by using a series of computation method. It avoids the repeated calculation of new structure, decreases the computational cost and accelerates the optimization procedure. Therefore, it is of great significance to research a quick and efficient reanalysis method.In this thesis, it firstly introduces several common numerical methods for calculation of generalized eigenvalue problem. In chapter 3,with regard to the variation of structure types(single degree of freedom on a node basis variation in quantity) in the structure modifications, such as the plate structure is changed into frame structure or truss structure is changed into frame structure, the extended CA algorithm is utilized for its numerical calculation, which is used the first order, second order and high order perturbations of initiating structure eigenvectors as a reduction base vector and combined with the Rayleigh Quotient. The validity of this method are verified by the results of numerical examples.In addition, the research on the reanalysis method of structural topology modification is implemented in chapter 4. This part is focused on the dynamics reanalysis technology of structural topology modification with added degree of freedom(DOF). Basing on the dynamic condensation, Rayleigh-Ritz Method and the coupled relationship between old and new degree of freedom for modified structure, two computational methods of dynamics reanalysis with high precision are put forward by combining the CA algorithm and independent Rayleigh-Ritz Method. The simulation results of dynamics reanalysis examples for truss, frame and plate topological modifications indicate the availability and high-efficiency of those methods. Besides, by considering the modifications with added mass in nodes of modified structure or the second modification and other complex topological modification situations, the further research for the adaptability of these methods are verified by numerical examples.