Optimization of Forged Magnesium Structural Automotive Components

Abstract

In an ongoing search for better vehicle fuel economy, the automotive industry has put significant emphasis on the reduction of vehicle weight while retaining stringent safety, quality and performance standards. With its high specific stiffness, strength, and fatigue performance under typical automotive service conditions, forged magnesium is a potential material to fill these requirements. Investigating an existing front lower control arm, engineering specifications were developed to evaluate the performance of a forged magnesium replacement. Combining a design volume derived from a kinematic CAD model and the produced engineering specifications, an optimization design space was created, and a component optimized within it using Altair Optistruct. Based on this optimized result an initial design was created in CAD, and design-analysis iterations conducted until it was structurally equivalent to the baseline design. This initial detail design produced a mass savings of 39% over the benchmark cast aluminum control arm, and only failed to challenge it in fatigue. It is expected that future designs will improve fatigue performance with little added mass, while continuing to integrate improving knowledge about the forging and mechanical performance of magnesium alloys.