WCX17: FCA Reveals ‘Hole-Istic” New Lightweighting Approach

April 6, 2017

Bill Visnic

A new design simulation process developed by FCA identifies areas of a truck frame that can be drilled to reduce weight without affecting strength (CAD illustration: FCA).

Engineers at FCA revealed at the SAE WCX17 conference in Detroit a new simulation and analysis design tool that can earmark nearly any suitable component for a strategic hole-punching process that can significantly reduce the part’s weight.

Crossmember of a truck frame indicating areas suitable for lightening holes or slots (FCA).

Using a pickup-truck frame as an example, engineers reduced its weight by 15 lb (7 kg) but cutting optimally-placed-and-sized holes and slots. The cutouts are located at places that the analysis shows have no impact on the frame’s fatigue or durability properties. By using two specific new simulation algorithms that discretely focus on fatigue performance as the design target, the simulation reveals non-critical areas that are over-engineered and thus are potential candidates for drilling holes or slots to remove material.

The new design simulation enables mass reductions of 3-5% in a large component such as a truck frame.

Engineers presenting the results of the prototype process said that by first focusing on fatigue performance as the design target, the need for intermediate design goals is eliminated, so the new process itself is highly efficient and can help reduce development time. And they said the algorithms used in the process can be applied to the design of nearly any component.

The engineers who authored the SAE technical paper (2017-01-1348) describing the new simulation approach, Barry Lin, Ramachandra Bhat, Shawn Zhang, Taylor Sykes-Green, Nitin Sharma and Kevin Thomson, explain: “Comparing to other optimization processes which typically convert fatigue targets to other design targets such as stress targets, this lightening-hole approach directly uses fatigue targets in the process. It eliminates the need to create intermediate targets and simplifies the whole process.”

The strategy can be easily integrated into conventional design and analysis processes, the authors added.

An FCA engineering source said that although the company has in the past drilled holes in components to lighten them, this new process has yet to be deployed in the design of a production component. However, it seems likely it will soon be used—perhaps to reduce mass in the next all-new Ram pickup, for example, which is scheduled for 2019 launch and will continue to use a steel ladder chassis and predominantly steel cab.