Design Improvement of an Automotive Rack Housing

This work presents the design nationalization procedure of an automotive rack housing. The main objective of the project was basically the product optimization, that was made by: material reduction; reduction of the number of components; manufacturing costs reduction; ease of assembly; and ease of manufacturing. The current design of the product, formed basically of a component made of steel bar and other one made in cast aluminum, in addition to bushings, inserts and other details was replaced by a new component completely built in cast aluminum alloy. The rack housing wall was reduced and ribs were added to it to increase its stiffness. Thus the total mass of the product was reduced in 13% and the total number of components was reduced in 21%. Structural calculations were made according internal procedures of the company both for the current design and for the proposed one. Quasi-static nonlinear structural analyses were made considering the elasto-plastic and the hyperelastic behavior of the materials, in order to check the possibility of failure by yielding, plastic collapse and ductile fracture. Besides, modal analyses were made in both designs in order to evaluate the dynamic behavior of the structures. It was guaranteed that the proposed design presents higher safety factors than the current design and higher stiffness too, allowing the structure to work free of resonances in the range of operation frequencies of the vehicle.