Designing and developing lightweight shoulder seat belt brackets for NASCAR

Developing lightweight race car components

Roush Fenway Keselowski Racing (RFK Racing) is a motorsports team founded in 1988 and headquartered in Concord, North Carolina. The team serves the automotive industry as a successful racing company with eight championships, including back-to-back NASCAR Cup titles in 2003 and 2004.

When designing components for race cars, driver safety and performance are a priority. To optimize performance on the track, it’s important to ensure all components in the race car are as efficient and lightweight as possible. To make sure that all components of the race car are safe, NASCAR provides design requirements and specific tests that the parts must pass. The RFK Racing team felt that they could adhere to these requirements, while producing lighter, more efficient components.

With the help of Siemens Digital Industries Software, RFK Racing used Siemens solutions to design and create specific driver safety components for its race cars. The team used NX™ software, Simcenter™ Nastran software and Teamcenter® software to develop brackets that attach the seat belts to the seats. These same tools are used at RFK Racing to develop numerous parts for NASCAR Cup Series race cars.

All of these solutions are part of the Siemens Xcelerator business platform of software, hardware and services.

Using FEA to develop parts more efficiently

One of the most important requirements for this driver safety component is that the part must be strong enough to pass specific load testing to be approved for competition. The part must have an efficiently designed structure with all the required strength but no excess material. RFK Racing was heavily reliant on finite element analysis (FEA) to get the part right the first time. Time-to-market is critical in the racing industry, and since these parts are expensive to make, RFK Racing did not want to waste any time on multiple design iterations to get it to pass the load test.

RFK Racing used Siemens solutions to overcome these design challenges in several ways. The team used NX to create a model-based definition (MBD) and 2D drafting documentation to define the shoulder belt brackets. They used Simcenter Nastran to optimize the brackets for both strength and mass.

“Our purchasing department can access and reference everything related to this project within Teamcenter, from the CAD and FEA studies to the release drawings, streamlining future orders and production quotes,” says Will Chen, design engineer for RFK racing.

They also leveraged Teamcenter to connect the design, purchasing and assembly departments with the models to efficiently design, manufacture and install the shoulder belt brackets. “NX provided all the tools we needed from start to finish; everything
from analyzing early concepts against 3D scans to creating the final release drawings,” says Chen.

The RFK Racing team was able to iterate and optimize the shoulder belt bracket design in the computer-aided design (CAD) environment to quickly and efficiently optimize the brackets for the required safety factor and minimum mass. Using Simcenter Nastran gave RFK Racing
enough confidence in the results that they were able to skip the prototyping phase and perform the required NASCAR load testing on components from the initial production run. This cut weeks out of the time-to-market. “We were able to iterate our design in a very short amount of time using Simcenter Nastran and had finalized drawings in less than 3 weeks,” says Chen.

As a result of skipping the prototyping stage, RFK Racing was able to have stronger, safer and lighter parts on the car six weeks sooner. “Our new seat belt brackets are up to 78 percent lighter than our previous designs, while achieving a higher safety factor due to extensive structural optimizations made using Simcenter Nastran,” says Chen.

The test parts were pulled from the production order, substantially reducing the piece price. Using Siemens solutions allowed RFK Racing to optimize the bracket design to reduce weight and ensure consistency. The team used Siemens solutions to improve the design and efficiency of the seat belt brackets for RFK Racing, which translated to improved performance on the racetrack. RFK Racing plans to continue using Siemens solutions to streamline its
design and racing performance.