Integrate Topology/Shape/Size Optimization into Upfront Automotive Component Design

Abstract

Design optimization has gained significant reputation in the automotive industry because of its capabilities on helping cost cutting, weight reduction, and performance improvements for various products. It has become a valuable tool in the product development processes, and many CAE codes are developing or integrating the design optimization capabilities into their solvers to meet users' demand. Topology, shape and size optimization has been widely used to improve the product performance from the structural perspective. Topology optimization explores the initial topology of various product designs with constrained packaging spaces and design requirements. The technique can be easily applied to shell structure with shell design domain or 3D solid structures with 3D solid design domains, even though it takes extra effort to interpret the final topology optimization results for manufacturability. Nevertheless, it is still a considerable challenge to explore shell like structures with 3D solid design domains by using topology optimization tools. Manufacturing consideration such as injection molding is another challenge in developing shell like structures from 3D packaging spaces using optimization; currently there are no tools available address these types of problems directly. Manufacturing constraints like extrusion has recently become available in some commercial optimization codes. It provides some help on addressing the manufacturing issue but it did not provide any solution to the posed problem⎯develop shell like structures from 3D solid design domains. This paper proposes a two-stage topology optimization approach to develop optimal shell like structures from 3D solid design domains. The final topological design from the two-stage topology optimization analysis was then revised by designers to include design features. After that shape and size optimization was utilized to further improve the design. An injection molded plastic carbon canister bracket has been used to demonstrate the proposed approach. The main function of the carbon canister bracket is to carry the carbon canister, fuel tank isolation valve, canister vent valve, and dust box; the bracket must also meet vehicle durability requirements for dynamic load without loss of any component functions or developing any cracks. From a given 3D package space, an optimal bracket design was found based on the proposed topology optimization approach. A production ready design was created based on the topology optimization results and design features from Knowledge Based Engineering (KBE) library. Shape and size optimization was utilized to further improve the bracket design. The final design showed much better performance than the original design. The collaboration among CAD designers, product engineers and CAE engineers played a crucial role to the success of the proposed design approach.