Development of Lightweight Hanger Rods for Vehicle Exhaust Applications 2017-01-1709
Recent stringent government regulations on emission control and fuel economy drive the vehicles and their associated components and systems to the direction of lighter weight. However, the achieved lightweight must not be obtained by sacrificing other important performance requirements such as manufacturability, strength, durability, reliability, safety, noise, vibration and harshness (NVH). Additionally, cost is always a dominating factor in the lightweight design of automotive products. Therefore, a successful lightweight design can only be accomplished by better understanding the performance requirements, the potentials and limitations of the designed products, and by balancing many conflicting design parameters. The combined knowledge-based design optimization procedures and, inevitably, some trial-and-error design iterations are the practical approaches that should be adopted in the lightweight design for the automotive applications. In this paper, the strategies and approaches to achieving lightweight designs are reviewed and discussed, with emphasis on the integrated consideration of material, structure, joining and system integration, and optimization. The implementation of these strategies and approaches into the design of vehicle exhaust product is demonstrated with two case studies: (1) the material selection for the design of a round hanger rod, which can be considered as an idealized vehicle hanger rod, and (2) the structural optimization of the hanger rod and the joining designs with a variety of improved functions and flexibilities.