Title: Product design optimisation with microstructure-property modelling and associated uncertainties

Authors: K.N. Solanki, Erdem Acar, M. Rais-Rohani, M.F. Horstemeyer, W.G. Steele

Addresses: Center for Advanced Vehicular Systems, 200 Research Blvd., Starkville, MS 39759, USA. ' Department of Mechanical Engineering, TOBB University of Economics and Technology, Sogutozu Cad. No. 43, Sogutozu, Ankara, 06560, Turkey. ' Aerospace Engineering Department, Mississippi State University, P.O. Box A, Mississippi State, MS 39762, USA. ' Mechanical Engineering Department, Mississippi State University, Mail Stop 9552, 210 Carpenter Building, Mississippi State, MS 39762, USA. ' Mechanical Engineering Department, Mississippi State University, Mail Stop 9552, 210 Carpenter Building, Mississippi State, MS 39762, USA

Abstract: In this paper, we present a methodology for simulation-based product design optimisation using an internal state variable (ISV) constitutive modelling approach that captures the microstructure-property relations in the material. By modelling the stochastic uncertainties in the material model and the loading conditions, the design optimisation problem is formulated and solved using the reliability-based design optimisation (RBDO) methodology. The application problem considers the design optimisation of an A356-T6 cast aluminium component under maximum stress and damage constraints. Alternative metamodelling techniques are used to develop appropriate surrogate models in lieu of direct coupling of non-linear static finite element analysis and numerical design optimisation. Probabilistic design constraints are modelled using the safety index approach with the solution of the nested optimisation problem facilitated with the help of analytical surrogate models. Comparison of the optimisation results reveals the importance of using an ISV-based constitutive model that is sensitive to the growth of damage in material. Moreover, the solution of the RBDO problem captures the effects of uncertainty on finding the minimum weight design for the cast component.

Keywords: reliability based design optimisation; RBDO; shape optimisation; metamodelling; response surface methodology; RSM; microstructure-property relations; constitutive modelling; design under uncertainty; microstructure; simulation; product design; aluminium casting.

DOI: 10.1504/IJDE.2009.028446

International Journal of Design Engineering, 2009 Vol.2 No.1, pp.47 - 79

Published online: 17 Sep 2009 *

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