Akcay-Perdahcioglu, D.

de Boer, A.

Ellenbroek, M.H.M.

English

University of Twente Research Information

A Hybrid Design Optimization Strategy forThe Field of Structural DynamicsD. Akçay Perdahcıoğlu, M.H.M Ellenbroek, A. de BoerInstitute of Mechanics, Processes and Control - TwenteChair of Structural Dynamics and Acoustics, University of TwenteP.O. Box 217, 7500 AE Enschede, The Netherlandsphone +31-(0)53-4895618, email d.akcay@utwente.nlIntroductionThe occurrence of dynamic problems during theoperation of machinery may have devastating effectson a product. Employing design optimizationtechniques may help to ensure the safety and thereliability of the product.Objective & ApproachThe objective of this project is to develop a hybriddesign optimization strategy that can be benefited forsolving dynamic problems of structures.The developed strategy is presented in Figure 1.Keywords: Design of Computer Experiments(DOCE), Component Mode Synthesis (CMS), NeuralNetworks (NN), Genetic Algorithms (GA), SequentialQuadratic Programming (SQP).ApplicationTo demonstrate the strategy, a structure illustratedin Figure 2(a) is considered. The thicknesses ofthe struts are selected as the design parametersand the struts which have n π2 , n = 0, . . . ,3 rotationaldistance between each other are assigned to havethe same thickness values. The model of thecomplete structure is generated by modeling only onerepeating component. The initial design is shown inFigure 2(b). The optimization problem is formulatedas:minthckiρV (thcki)sbj. to f5 = 750MAC5 ≥ 0.90.1≤ thcki ≤ 0.5 i = 1, . . . ,6.The results are summarized in Table 1 and the finaldesign is shown in Figure 2(c).UPPER LEVEL (Structure Level)Problem AnalysisLOWER LEVEL (Component Level)Component Component-n Component... ...Calculate the system matricesof each configuration accordingto the information provided byDOCE using CMSDOCEFE models of each component (one parameterized FE modelfor repeating components)Save them in Component-nLibraryIf no design parameters in thatcomponent, calculate thecorresponding system matricesonly once using CMSAssemble + SolveTraining SetSurrogate Model ( )NNOptimization ( )GA-SQPValidation ( )CMS ModelLOWER LEVEL (Component Level)Component Component-n Component... ...Sought the system matrices ofthe optimum design parametersin the libraryExistNOCalculate and save in thelibraryYESAssemble + SolveCompare with NN ModelAccuracyO.K.?NOYESAdd optimum design parameters and thecorresponding CMS model responseSTOPFigure 1 : The developed hybrid design optimization strategy.Initial Design Parameters [0.3 0.3 0.3 0.3 0.3 0.3]Optimum Design Parameters [0.1 0.298 0.329 0.297 0.1 0.1]# of designs in the Library (Initial) 60# of designs in the Library (Final) 349Total # of iterations 89Initial Mass 0.4936 kg.Optimum Mass 0.3899 kg.MAC5(NN) 0.9866MAC5(CMS) 0.9817Final f5(NN) 750 Hz.Final f5(CMS) 749.33 Hz.Table 1 : Summary of the optimization problem.xyz(a) The structure and its repeating component (b) Initial Design-Mode 5123456(c) Final Design-Mode 5Figure 2 : Application 

A Hybrid Design Optimization Strategy for The Field of Structural Dynamics

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A Hybrid Design Optimization Strategy for The Field of Structural Dynamics

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