WMU News

WMU puts 'brakes' on Chrysler product development

Nov. 19, 2001

KALAMAZOO -- With the help of an in-house PT Cruiser and a challenge grant from DaimlerChrysler AG, Western Michigan University engineers are making tracks in solving a problem that has already stumped six other research teams around the nation.

A $195,000 grant has been awarded by DaimlerChrysler to Dr. Mitchel J. Keil and Dr. Jorge Rodriguez, both assistant professors of industrial and manufacturing engineering, to study and develop methods to enhance the design of brake hoses and similar flexible parts in automobiles. The two-year challenge grant began in January, and in May, a 2001 PT Cruiser arrived on campus for use on the project. The vehicle was from DaimlerChrylser and Kalamazoo's Maple Hill Auto Center, a DaimlerChrylser dealer.

Keil says in this day of product development done primarily with computer-aided design software, one of the few design tasks that CAD programs cannot address involves the design of flexible materials that shift in shape and move through an allotted space during operation. The brake hose is a perfect example of such a part, and the lack of CAD modeling software to represent such parts has been plaguing automakers, causing production delays as engineers try to fit such flexible parts around the solid parts that have already been designed using sophisticated and precise CAD programs.

"What we have here is a big piece of floppy stuff that is critical to the safe operation of a car, but no one has been able to characterize the properties or predict accurately how it will behave," Keil says. "You really have to be able to model it and know how it's going to behave in the car."

A sample brake hose Keil keeps in his office illustrates the problem perfectly. The simple hose, which is just over a foot long, has fittings at both ends where it can be attached to solid parts. It also has plastic rings, or "bumpers," that have been added at points where the hose's mid-section comes into contact with a solid car part during operation. The rings were not part of the design, but added later as engineers discovered through trial and error how the hose behaved in operation. The bumpers act as safeguards to head off possible abrasion points that could lead to hose failure. While such adjustments do not present any safety problems, the need to make them causes time delays and leads to production setbacks.

Keil and Rodriguez have been adapting existing software to allow modeling of the hose and other flexible parts in a virtual environment. They have used their expertise in kinematics--or motion dynamics--as well as modeling and analysis, and they have used portions of WMU's arsenal of state-of-the-art CAD programs, including CATIA and ADAMS. Since Chrysler models its new products using CATIA software, Keil says one of the project goals is to develop ways for the hoses to be represented in their natural shape as solid materials in CATIA models.

The PT Cruiser gives the research team a "real-world" opportunity to check its data. When measurements taken from the vehicle fail to match those in the developing CAD model, the team duplicates the new data using a mathematical formula and adjusts its CAD model accordingly.

"We're not quite there," Keil says, but notes the team is making rapid progress and already has gotten positive feedback after technical presentations made at DaimlerChrysler headquarters in Auburn Hills, Mich.

With five or six undergraduates and a graduate student lending their talents to various parts of the project each semester, Keil says chances for a successful resolution to the longstanding problem are good. And as for those other six research teams that have tried and failed, Keil says those attempts have left the industry with a healthy skepticism about WMU's chances for success. But lately, the hose manufacturer's "here-we-go-again" attitude has begun to change as the WMU team has made significant progress.

"We should soon be able give Chrysler information about the hose properties that will allow them to optimize the design of that part," Keil says. "They've never had that opportunity before."

Media contact: Cheryl Roland, 616 387-8400, cheryl.roland@wmich.edu

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