Weight Optimized Design of a Front Suspension Component for Commercial Heavy Trucks

Design of suspension systems for Heavy Trucks is always challenging due to the heavy loads the system is exposed to and the long life requirements for the total system. Historical solutions were over designed structures to get the needed life and reliability. This always meant heavier parts. In today's economy, the vehicle weight of commercial heavy trucks is a very important feature for our customers and the end user. Lighter, well-designed suspension components provide better ride quality to the drivers through lower un-sprung weight, lower initial costs and greater payloads. The latest available structural optimization techniques are a business requirement for tomorrow's products. This paper describes the developed methodology used by DANA Engineers to design a weight optimized upper control arm for Commercial Heavy Trucks in step by step fashion.

The method starts with determining the loads on the component part. The next step is to define the maximum available space for this component by taking into account the motion of all the surrounding parts. A powerful feature of Pro/Engineer called Behavioral Modeling identifies the space claim envelope of the moving component under consideration. The external and internal space claims are identified and used for creating the initial block for the optimization process. Then, the topology optimization feature from ANSYS determines the load paths and identifies the least required shape. Topology optimization is very useful but it brings challenges to the designers since it usually describes very complex geometries to create in solid modeling environment. It is now up to the designer and analyst to interpret the resultant abstract form. The advanced features of Pro/Engineer enable an elegant design solution to the complex topology output. Variable section sweeps controlled by graphs, described in this paper, provide this solution. These non-intuitive shapes are the results of this methodology, and exist as an integral part of the process. Final shape optimization is also included in this paper. These methods can be efficiently applied to weight optimization on any structural component.