Making A Positive Impact: Bayer Materialscience And O-Flex Automotive Collaborate On Innovative Bumper System That Meets New Pedestrian Protection Requirements
Pittsburgh, PA - Bayer MaterialScience LLC (BMS) and O-Flex Group, Inc. – one of the leading suppliers of passive energy absorbing solutions for interior occupant protection – have collaboratively developed a family of innovative bumper system energy absorbers to meet new pedestrian protection requirements. The O-Flex bumper assembly consists of energy-absorbing tubes, utilizing Bayfill EA (energy absorbing) polyurethane foam, that are collapsible upon impact.
The bumper system, currently developed for the Cadillac STS, complies with European Commission pedestrian safety legislation and crash compatibility bumper height requirements.
The new product is a metal spin-formed, composite-bonded, quadrangular cross-section tube with extremely tight, corrugated walls. The patented tube produces a nearly perfect square wave force upon impact and can withstand a series of multiple impacts with virtually no degradation in force level or energy absorption efficiency.
"The square wave efficiency actually improves after each subsequent impact with an extremely small permanent set after each impact," said Paul Glance, Ph.D., M.E., application engineer for O-Flex Automotive, Inc., a division of O-Flex Group. "The metal construction also produces a consistent square wave force level at high and low temperatures. Furthermore, it is unaffected by humidity and aging, which sometimes degrades plastic energy absorbers."
While improving performance, the specific cost and mass of the new energy absorber is the same as current solutions utilizing alternative 4.0 PCF foam. By working with BMS, O-Flex leveraged the company's technology and resources to identify a lower density polyurethane foam for the application and develop prototypes for testing.
"We found that the special ultra-low-density Bayfill foam enhances the multiple impact capability of the new bumper prototype," noted Glance. "We never really considered any other material."
Doug Stratton, project leader, Future Business Automotive Industry Innovation, BMS, observes that European Commission pedestrian impact regulations are driving new design and material solutions globally. In the U.S., the National Highway Traffic Safety Administration (NHTSA) announced initiatives at 2005's American Plastics Council Automotive Work Group conference focusing on crash compatibility among a wide range of vehicles.
"O-Flex Automotive's new design concept, based on Bayer MaterialScience's energy-absorbing Bayfill EA foam, is a lightweight, yet highly effective solution for energy displacement/absorption and pedestrian protection," said Stratton. "These bumper assemblies are ahead of the curve and meet NHSTA and IIHS crash test ratings per vehicle type."
According to Stratton, the design flexibility of polymeric materials appeals to automotive engineers who are discovering that the replacement of traditional steel-and-aluminum bumper assemblies with custom energy absorber systems results in bumper systems that are more durable, integrate more components and reduce the overall weight of the vehicle. Collaborations similar to the one Bayer MaterialScience has undertaken with O-Flex could translate into the development of a broad range of valuable materials, design and process solutions that not only comply with European and Asian timelines for improved energy absorber systems, but also lead the pace in the Americas, Stratton points out.
In addition to its versatile Bayfill EA foam, BMS offers a complete portfolio of products that can be incorporated into bumper beam and front-end module designs, including Bayflex polyurethane-reinforced, reaction-injection-molding (RRIM) high-performance polymer systems; Baydur rigid-polyurethane, structural-foam RIM systems with Long Fiber Technology (LFT); Makroblend polycarbonate/polyester blend resin; and TP231 film.
O-Flex Automotive, Inc. is located in Rochester Hills, Mich., and is wholly owned by O-Flex Group, Inc. O-Flex Group, Inc. is wholly owned by OHTSUKA CO., LTD of Tokyo, Japan. O-Flex Group, Inc. is the North American leader in the development and manufacturing of corrugated tubing used for vehicle occupant crash protection (O-EA).
SOURCE: Bayer MaterialScience LLC