Development of a lightweight frame for a 40-foot flatbed trailer by using CAE-based structural optimization

Abstract

In this study, a novel ultra-lightweight frame for a flatbed trailer is developed; it has a completely different layout from conventional ladder-type frames and is developed by applying structural optimization using commercial computer aided engineering (CAE)-based software. The proposed process of design optimization consists of two main steps: an initial design step to obtain the optimum layout (or topology) of the structure and a size/shape optimization step to determine its detailed geometric dimensions. In the topology optimization step, an initial design of the frame is generated to obtain the maximized global system performance measures, such as static stiffness or natural frequencies, for which GENESIS, a commercial optimization software package, is used in this investigation. For size and shape optimization, thicknesses of the member plates and the boundary shapes are optimized by using the Taguchi method, in order to minimize further the mass of the frame without violating design constraints on local performance measures such as the allowable stress limit. In addition, manufacturability is also considered during the detail design step of size and shape optimization. As a result, the optimized lightweight frame has improved bending and torsional rigidities while its mass is reduced by 24.5 per cent as compared to that of the original model.