Topology optimization of vehicle rear suspension mechanisms

Abstract

As suspensions critically affect the ride and handling performance of vehicles, considerable efforts have been made to improve their design by an optimization method. In this paper, we propose a topology optimization-based method for suspension synthesis by using a 3-dimensional model constructed with nonlinear bars and zero-length springs that discretize the 3-dimensional space between the chassis frame and a vehicle wheel. For optimization, bar cross-sections and spring stiffness values are used as design variables alongside the nodal positions of bar elements as shape optimization variables to simultaneously optimize the topology and shape. To verify the proposed approach, 2 types of design problems were solved: recovering known suspension mechanisms for a given set of wheel trajectories and synthesizing unknown suspension mechanisms that satisfy several design constraints typically used in the automobile industry. Through these examples, possibilities to design new and advanced suspensions by the proposed optimization method are clearly demonstrated. in a reasonable amount of time. Therefore, we hope to set up the topology optimization problem for suspension synthesis by using a numerically efficient gradient-based optimizer.Although there is no study or report that uses the topology optimization method for 3-dimensional vehicle suspension systems, there were earlier studies that dealt with planar linkage mechanisms by topology optimization. To synthesize 3-dimensional suspension systems, a recently proposed energy-based formulation developed for planar mechanisms 5 will be expanded by first reviewing earlier studies that discussed issues and difficulties with rigid body mechanism synthesis using the topology optimization method.Kawamoto 6 proposed a ground model consisting of nonlinear bar elements for the topology optimization-based synthesis of planar linkage mechanisms. An alternative modeling method is to use spring-connected rigid blocks (SBs). 7-9 Whether bar elements or spring-connected rigid blocks are used to make a ground model, mechanism layout determinations, which are discrete in nature, are expressed in terms of continuous design variables since a gradient-based optimizer cannot be used otherwise. As explained below, continuous variables cause major issues even though they cannot be avoided for efficient calculations. Besides aforementioned studies, other relevant studies 10-16 were reported. However, realistic problems appearing in engineering applications could not be solved until recently because of the discrete-type DOF (degree of freedom) constraint, which is something a rigid body mechanism must satisfy. This is not easy to express in the differentiable form when continuous design variables are used to develop a gradient-based topology optimization method. If a mechanism with a single input and a single output is to be synthesized, its DOF should be exactly 1. It is only recently that the DOF issue has been resolved by Kim and Kim 5 for the planar linkage mechanism synthesis by showing th...

Computational synthesis of wheeled vehicles via multi-layer topology optimization

“…One study by Luo et al [33] synthesizes mechanisms by optimizing the number, type and location of joints connecting overlapping planes. Another by Kim et al uses topology optimization to design the rear suspension linkage of a vehicle using simple bar and spring elements [34], and in one study by Briot & Goldszetejn [35] the structural topology of the links in a five bar mechanism were optimized. Here the rigid body representation was defined beforehand and the link sizes were not optimized by the algorithm.…”

Finite element analysis and experimental study of strain for a vehicle rear suspension

“…This component must have high elasticity and resistance to fatigue, so from the design phase of such a component the aim is to optimise the design, reducing stress concentrators [13,14,15]. Obviously for validation of the automotive component, tests performed on test stands are required [16,17].…”

A generalized method for three-dimensional dynamic analysis of a full-vehicle model

“…Tanik and Parlaktas 4 introduced a kinematic model for the kinematic analysis of the double-wishbone suspension mechanism. Kim et al 5 proposed a topology optimization–based method for the synthesis of the rear spatial suspension mechanism. All the aforementioned works, however, only explained the relative motion between the wheel and the vehicle body.…”