ALGOR SOFTWARE HELPS ASU TEAM DESIGN WINNING RACE CAR

The Arizona State University Formula-SAE car in action. The car won the "Best Engineered Design" award in the 1992 competition.

This Fall, a team of engineering students at Arizona State University in Tempe is working to improve the design of an open-wheel race car that has already won several awards. The new car will be entered in the next Formula-SAE competition in the Spring of 1993.

Real-World Experience

Formula-SAE is a national competition which provides student engineers with a real-world project, challenging the skills they have developed in the classroom. The annual event, sponsored by the Society of Automotive Engineers (SAE), requires students to design, analyze, manufacture, test and race a formula-style car. Entries are judged on the quality of their design, before being put through several performance tests.

Tough Act to Follow

The 1993 team has their work cut out for them. In the 1992 event, Arizona State University's entry won four design and performance honors including the coveted "Best Engineered Design" award. The 1992 team utilized Algor design and analysis software in the creation of their car, which has a chassis made of advanced carbon fiber composite materials. They also analyzed several other critical components.

According to ASUSAE Chairman Merrill J. Keck, "We were not able to analyze and optimize every design component due to time constraints. That will be a task for 1993. We did, however, complete analyses on most of the high-stress members and were able to attain significant weight and materials reductions while retaining structural integrity."

The Arizona State University Formula-SAE team is shown here with their 1992 entry.

Tricky Design

Perhaps the most ambitious project involved the design and analysis of the car's "tub" or chassis, which was performed by Formula team captain Joe Boyle. The original tub model was created using Unigraphics II software at McDonnell Douglas Helicopter Company, another team sponsor. The first step was to transfer the geometry into Superdraw II. "In Superdraw," says Mr. Boyle, "elements were created manually and by using the automesh option. Two material files were created. The first used steel to save CPU time while any design glitches were eliminated. Once the model was running smoothly in steel, a composite material file was created."

The analysis was designed to confirm that both stress and torsional rigidity levels were within an acceptable range using a composite layup orientation, called QUASI, which is standard in the aircraft industry. The material file was created to meet this specification.

According to Mr. Boyle, "Several analysis runs were performed in an effort to correctly apply loads and boundary conditions to the model. The boundary conditions were designed to model the effects of fixing the front suspension bulkheads to a bedplate, while allowing the rest of the car to rotate about the y-axis. " The magnitude of the distributed moment about the y-axis was based on the maximum force the rear wheel would experience," continues Mr. Boyle.

"The moment arm associated with this force was determined to be half the rear track of the car. Because the applied moment was distributed among only nine nodes, the stress at that location was higher than the allowable level. This led us to increase the mesh density in that area, distributing the moment among 27 nodes, which brought overall stress into the acceptable range."

Other Analyses

The ASU team also utilized Algor software to analyze an aluminum rear bulkhead, which serves as the connection point for suspension components and provides lateral stiffness to the tub. The goal was to optimize a series of cutouts to reduce weight while maintaining a significant safety factor.

"The original design consisted of twelve complicated cutouts and could be called the swiss cheese effect," says Mr. Keck. "After three analysis runs, we reduced the number of cutouts to four and the weight dropped by 25%. This greatly simplified the machining and lowered our costs."

This composite failure contour shows high stress areas in the chassis, or tub of the Arizona State University Formula-SAE race car.

BEdit Speeds Analysis

Another critical analysis involved the use of Algor's BEdit Beam Design Editor to determine the minimum outside diameter and wall thickness requirements for the lower, rear suspension control arm. This component receives the highest load from acceleration, due to engine torque and longitudinal weight transfer.

"In this case," says Mr. Keck, "We had to keep deflection and stress within acceptable levels while using readily available materials. We performed four very quick iterations using BEdit, with different tubing specifications. As a result, maximum stress was lowered by 25% and deflection was reduced by 35% with a weight increase of only 15%."

Team Commitment

The Arizona State University team endured many months of long hours and tough challenges to get their car to the event, which was held at the Ford Engineering Center in Dearborn, Michigan. In addition to the award for Best Design, the team also won cash awards for Best Use of Composites, Best Prototype Fabrication and Best M85 (methanol) Fuel Economy. They received honorable mention for Suspension Design and M85 Design Conversion.

In the racing events, the team did very well until a driving slip-up, followed by a mechanical failure, cost them significant time in the endurance race. Even with these setbacks, ASU finished a respectable 22nd overall out of 71 entries.

"Taking first place in design made the year's work worthwhile," says Mr. Keck. "More important though, is the engineering education that each student received. Much of what we learned is not taught in the regular college curriculum."

For 1993, ASU plans to optimize many more of the car's components using Algor software and increase the amount of practice time given to the drivers. The 1993 competition will be held in the Spring and cosponsored by the Chrysler Corporation.

Virginia Tech University Formula-SAE team

Virginia Tech Gears Up for '93

The below picture shows the 1991/1992 Formula-SAE team from Virginia Tech University with Algor Vice President, Science and Technology, W. Charles "Chuck" Paulsen (right).

This highly successful team, led by faculty sponsor Robert Wynn, won the 1991 event and finished third overall in 1992. They have now teamed up with Algor to develop a totally new race car for 1993. We'll be reporting on their progress in preparing the new car and on how they do in 1993. Look out ASU!