Control Arm Design Utilizing Multi-Material Topology Optimization

Abstract

With the rising cost of fuels in addition to stricter emission standards, modern vehicles ought to be more fuel efficient. The best approach to increase fuel efficiency is to reduce the mass of vehicles. In order to produce light weight components for vehicles, topology optimization (TO) is now widely used by designers. However, the raw results obtained from TO cannot be manufactured directly and require significant reinterpretation to be able to be manufactured using traditional manufacturing processes. By considering the manufacturing process outside of TO, a sub-optimal design is obtained. The consideration of process specific manufacturing constraints within the TO ensures that a more optimal design will be produced. Previously the complex designs produced by TO have been a barrier to its implementation as the components cannot be produced without excessive costs. By coupling manufacturing constraints with TO more optimal designs can be obtained. Traditionally TO is done with a single material (SMTO) to arrive at the optimal geometry for that material. Within the automotive industry, designs are typically dominated by steel but aluminum is becoming more common. With the objective to create lighter components for vehicles many other materials have been experimented with. The introduction of multi material topology optimization (MMTO) has allowed for the simultaneous optimization of material placement and material selection. By producing designs with multiple materials, the benefits of each material can be combined to produce the best design. To show the application of these powerful tools, an MMTO design space was created for an automotive control arm. The design was optimized with steel and aluminum materials to minimize the compliance of the component. This will provide the most structurally efficient control arm for the target design mass. When matching the mass of a conventional stamped control arm, design compliance reductions of up to 70.6% were found for typical MMTO, without manufacturing constraints. Applying manufacturing constraints resulted in compliance falling by up to 62.2% and 23.7%, compared to the conventional design, for extrusion and casting respectively. Within the optimization material ratio constraints are implemented to limit the usage of higher cost materials.