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Inverse Perturbation Method And Human-Computer Interactive Annealing Genetic Algorithm And Their Applications

Posted on:2002-06-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y B MiaoFull Text:PDF
GTID:1102360065456010Subject:Mechanical design and theory
Abstract/Summary:PDF Full Text Request
Modern optimum design of machine and engineering structures includes the following main contents: structure parameter optimum design, optimal shape design and layout optimization, which are interconnectional as well as mutually independent. With the development of modern complex machine and military equipment, much higher requirements are posed to the modern optimum design, among which dynamic optimum design and layout optimization are two key parts. This dissertation studies two important problems that are correlative with those parts. One of the problem is inverse perpurbation method which belongs to dynamic optimum design methods based on FEM analysis model; the other is hybrid annealing genetic algorithms based on human-computer interaction, which belongs to layout optimization methods. These methods form the importan basis of dynamic layout optimization, which can be applied respectively to the dynamic optimum design and layout optimization, and can be also applied synthetically to the dynamic layout optimization.1. Studies on Inverse Perturbation MethodDynamic optimization is an important part of modern mechanical optimum design. Comparing with structural static optimization, the implementing of dynamic optimization is more complicated and difficult. The reasons for that are as follows: (1) The objective function or constraints of the dynamic optimal models often appears as compound, implicit and high-order nonlinear function of the design variables, which makes it hard to implement sensitivity analysis, constraint treatment and optimally solving. (2) Structural dynamic analysis is a complicated and time-consuming task, repetitious structural reanalysis makes it more difficult to solve. (3) The general theory, method and program are complex for the engineering technical personnel to master and use. In order to solve the problems mentioned above, this dissertation studies dynamic optimum design method based on the FEM analysis model, which includes 4 aspects as follows:· A new inverse perturbation method is developed and advanced to solve the inverse problem with constraints of unacceptable frequency bands. Meanwhile, the analytic expression of inverse perturbed parameter ? is derived by taking the plate beam FEM model of rotor system as example, thus it may avoid or reduce reanalysis times. Further more, aims at the multi-value and indetermination characteristic of the inverse problem, a method to determine the value of the perturbed parameter (i = 1,2......,n) is proposed, whichcalculates the  's value according to the ratio of design variables' sensitivity.· An inverse perturbation method to the solution for inverse eigenvector problem is originally provided. According to the thought of inverse solution and the decomposition method of finite element stiffness and mass matrices, the explicit expressions of inverse perturbedparameter s and node increment of eigenvector are derived as well as the method to obtain the perturbed parameter t(i = 1,2,....,n). This inverse perturbation method makes it easyto exploit the designer's activity.· An inverse perturbation method to solve the inverse problem of structural static design is proposed. Taking advantage of non-negative character of finite element stiffness and mass matrices, the explicit expression of perturbed parameter is derived. At the same time, in view of full-stress design thought of divisional optimization strategy, this paper gives a new distribution expression of , according to the ratio of element stress 1 to the maximumstress max.· By applying the algorithms mentioned above to the optimum design of engineering examples, it proved that the algorithms are characterized in reducing or avoiding reanalysis times, and are feasible and effective.2. Studies on SAGA based on Man Machine interactionLayout plan optimization is a problem that frequently arises in engineering. The Complex layout problem in practical engineering usually contains many complex factors, some of the problems are hardly...
Keywords/Search Tags:Optimum desiqn, Dynamic optimal design, Eigenvalue, Eignevector, Inverse problem, Inverse perturbation, Layout optimization, Man-machine interaction, Hybrid annealing genetic algorithm
PDF Full Text Request
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