Optimization of Automotive Structure using Variable Stiffness Laminates

Abstract

Variable Stiffness Laminates are created by spatially varying the fiber orientation resulting in designs that makes use of curved fibers rather than Uni-directional fibers to tailor the properties to design requirement. The advent of automated manufacturing methods such as Automated Fiber Placement and Tailored Fiber Placement has made variable stiffness laminate more realistic and attractive for use in aerospace and automotive sector. Importance of light weight designs in automotive sector has received new interest due to the stringent emissions rules and entry of designs based on alternative energy. Within this context, this thesis intends to create variable stiffness design for an automotive part to investigate the possible improvements in structural responses compared to a design based on conventional laminates. The design is done based on 2D Finite element analysis coupled with a convex optimization that helps to generate steered fiber designs optimized for strength, stiffness and buckling. One of the important load case studied here is the Inertia Relief. Inertia Relief method is a computationally efficient way of analyzing rigid bodies without doing a dynamic analysis. The method was implemented in the finite element framework and the responses from the analysis were taken for optimization.
Final optimization of the structure showed that significant improvement in the objective responses can be achieved by using variable stiffness laminates over a conventional laminate design (UD). The result also implies that reduction in weight can be achieved if a variable thickness optimization is to be done on the model.