The Design Advisor software enables vehicle design decision makers to precisely and accurately study material selection tradeoffs in terms of cost, mass and greenhouse gas emission savings. Dr Don Malen of University of Michigan’s College of Engineering developed the Design Advisor and provides an easy-to-use Microsoft Excel file format that allows users to enter vehicle design scenarios for quick evaluation.
Several factors complicate material selection for an automotive component. First it is normally recognized that such decisions should be based on the effect on the overall vehicle system rather than considering only effects of the component. Secondly, the decision criteria include multiple characteristics. These characteristics address the following questions:
- How is the vehicle system mass affected by the material selection?
- How is the vehicle system cost impacted?
- How will fuel economy be impacted?
- How will environmental stressors be impacted over the life cycle of the vehicle system?
Malen stated that as these criteria are not combined easily as a single objective number, the decision maker must be presented with contributions of mass, cost, and greenhouse gas emissions so any tradeoffs between attributes can be recognized.
The Design Advisor software objective is to provide the decision maker with a tool to evaluate these component material selections contributions at a vehicle system level.
Malen stated that since these material selection decisions are often made quite early in the vehicle design cycle, the Design Advisor is configured to operate in that context, the only required inputs being the information which would be available during the vehicle planning stage. Due to the wide availability of Microsoft Excel on laptops, it was the chosen application. Malen stated that Design Advisor’s interface is intended to be intuitive and visual as the assumed decision maker may be someone other than an analyst. Due to the approximate nature of input data, a sensitivity analysis is done to allow changing of the input values to study the robustness of the estimates.
Case Study: Steel versus Magnesium Seating
An example use for the Design Advisor is to compare a seat component manufactured in steel or magnesium. With the information available in Figure 1, users input the component material and manufacturing method, define the comparative vehicle in terms of size and powertrain type, driving cycle and subsystem masses. The component may also be sized for the comparative vehicle mass, using the software’s benchmarking data to look at several vehicles for comparison. The resized component can then be used to evaluate secondary mass reduction potential in other subsystems which are mass dependent.
Figure 1. Available data for Design Advisor seat material comparison example
A comparison summary as shown in Figure 2 provides a very high-level insight into results for mass, cost and greenhouse gas emissions of the nominal (steel seating) vehicle relative to the resized (magnesium seating) in an easy-to-view table. With the least number of inputs, engineering teams can review the trade-offs that will be faced in a material substitution decision. In the case of the magnesium seating, while 5 kg are saved, it comes at a cost increase of nearly US$14.00 per vehicle. Additionally, greenhouse gas emissions are increased over the vehicle life cycle. Users can go to detailed results for each attribute at a mouse click.
Figure 2. Comparison summary of the Nominal (steel seating) and Resized (magnesium seating) vehicles
The mathematical models used in the Design Advisor derive from the research and findings of several projects supported by the Steel Market Development Institute, the Auto/Steel Partnership, WorldAutoSteel and USAMP.
Along with a complete version of the Design Advisor software, decision makers may download a user guide as well as case study examples geared to demonstrate and teach Design Advisor’s functionality and use.
This information has been sourced, reviewed and adapted from materials provided by WorldAutoSteel (World Auto Steel).
For more information on this source, please visit WorldAutoSteel (World Auto Steel).