Title: Update of coarse finite elements structural models for dynamic analysis identified from reference responses

Authors: Tiago M. Rocha; José F.B. Meireles; António C.M. Pinho; Jorge A.C. Ambrósio

Addresses: Mechanical Engineering Department, CT2M, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal. ' Mechanical Engineering Department, CT2M, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal. ' Mechanical Engineering Department, CT2M, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal. ' Mechanical Engineering Department, IDMEC, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001, Lisbon, Portugal

Abstract: Finite element modelling of systems with structural and mechanical joints, geometric details, materials with environmental dependent properties, among others, requires a higher model complexity and large computation time. Finite element updating techniques aim at improving the models by increasing their accuracy without increasing their size. This work proposes an approach to finite element updating based on the minimisation of the modal assurance criteria matrix. The objective is to identify a model for which the natural frequencies and mode shapes match those of a reference model. The model material and geometric properties are the design variables being the sequential quadratic programming the optimisation method used. The non-convexity, and eventual discontinuity, of the design space leads to many local minima. This work proposes a search strategy for the initial values of the design that covers the feasible space being the global minimum identified among the different minima obtained from each optimisation problem.

Keywords: finite element method; FEM; finite element updating; optimisation; modal assurance criteria; MAC; alternate search modal assurance criterion; ASMAC; modelling; natural frequencies; mode shapes.

DOI: 10.1504/IJMMS.2011.043079

International Journal of Mechatronics and Manufacturing Systems, 2011 Vol.4 No.5, pp.402 - 414

Published online: 07 Mar 2015 *

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