Automotive Hood Panel Design Utilizing Anisotropic Multi-Material Topology Optimization 2021-01-0361

Topology optimization (TO) represents an invaluable instrument for the structural design of components, with extensive use in numerous industries including automotive and aerospace. TO allows designers to generate lightweight, non-intuitive solutions that often improve overall system performance. Utilization of multiple materials within TO expands its range of applications, granting additional freedom and structural performance to designers. Often, use of multiple materials in TO results in material placement that may not have been previously identified as optimal, providing designers with the ability to produce novel high performance systems. As numerous modern engineering materials possess anisotropic properties, a logical extension of multi-material TO is to include provisions for anisotropic materials. Herein lies the focus of this work.

A TO algorithm capable of considering anisotropic material properties is used to investigate a case study on the design of an automotive hood panel. A baseline aluminum hood panel is used to generate stiffness targets for optimization, followed by the generation of a design space model to allow the algorithm to determine optimal material placement. Optimization is undertaken with two types of AS4 continuous carbon fiber reinforced epoxy, each in two orientations. Optimal hood panel solutions that maintain stiffness levels of the conventional baseline are achieved. The mass of the design space is minimized, and constrained through the baseline displacement values. The effect of hood panel thickness and offset distance between panel layers is also investigated.

The optimal topologies indicated an overall mass savings of up to 44.5% in relation to the baseline, while maintaining hood panel stiffness. Comparative mass savings decreased as hood panel thickness increased and offset distance decreased. The allocation of stiffer materials was observed near locations of applied loads and constraints, with highly anisotropic materials placed along hood panel extremities. The practicality of anisotropic multi-material TO in lightweight design was thus demonstrated.