Title: Simulation-based design optimisation to develop a lightweight body-in-white structure focusing on dynamic and static stiffness

Authors: Morteza Kiani; Hirotaka Shiozaki; Keiichi Motoyama

Addresses: Center for Advanced Vehicular Systems, Mississippi State University, Mississippi 39762, USA ' Mitsubishi Motors Corporation, 1 Nakashinkiri, Hashime-cho, Okazaki Aichi Prefecture 444-8501, Japan ' Center for Advanced Vehicular Systems, Mississippi State University, Mississippi 39762, USA

Abstract: Through finite element simulations, static and dynamic stiffness of the body-in-white (BIW) model are investigated. Design of computer experiments through Latin hypercube sampling (LHS) is used to sample the vehicle design space defined by the wall thicknesses of 20 parts. Radial basis function (RBF) is used to generate separate surrogate models for selected responses including bending, torsion, lateral and longitudinal stiffness as well as the fundamental natural frequencies. A non-linear constrained optimisation for mass minimisation is formulated and solved under two different cases. In the first case, the BIW model was optimised under just vibration whereas vibration and stiffness requirements are included in the second case. Results show that the noise-vibration-harshness (NVH) performance of the car improves when both vibration and stiffness requirements are included in the optimisation. This guideline not only reduced the mass but also improved the body structure stiffness (static and dynamic) as the basic criteria of body design.

Keywords: car body structure; BIW; body-in-white; NVH; vehicle noise; vehicle vibration; harshness; simulation; design optimisation; lightweight car bodies; dynamic stiffness; static stiffness; modelling; vehicle design; finite element method; FEM; design of experiments; DOE; Latin hypercube sampling; LHS; wall thickness; radial basis function; RBF; surrogate models; bending; torsion; natural frequencies; nonlinear optimisation.

DOI: 10.1504/IJVD.2015.069467

International Journal of Vehicle Design, 2015 Vol.67 No.3, pp.219 - 236

Received: 29 Nov 2012
Accepted: 02 Apr 2013
Published online: 18 May 2015 *

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