A composite part on the 2021 Jeep Grand Cherokee L used new materials and technology to achieve 20 percent weight savings.
BASF Corp., L&L Products and Stellantis won the Altair Enlighten Award for their composite tunnel reinforcement, which launched in May.
The fiber-reinforced pultruded insert, overmolded with thermoplastic inserts, allowed the partnership to "develop something that hasn't been used before," Hank Richardson, product engineer at L&L, said Aug. 4 at the Center for Automotive Research's annual Management Briefing Seminars in Traverse City, Mich.
The award-winning part, located on the underside of the vehicle and a part of the overall transmission mounting system, replaces the concept of a high-strength steel clamshell with steel inserts.
It is Amsterdam-based Stellantis' first composite component of its type on a high-volume production car, Richardson said. It is also the first time that Florham Park, N.J.-based BASF's Elastocoat 74850 polyurethane pultrusion resin system has been launched on this kind of part.
"Stellantis gave us some freedom to be able to package it different, which allowed us to save some more weight," Richardson said.
L&L packaged the part into a smaller configuration to design into the vehicle's structure and take mass out of other associated parts.
The composite's strength-to-weight ratio was three times greater than any metal solution, he said, including magnesium, aluminum and high-strength steel, allowing for less CO2 emissions and better gas mileage.
The technology can also be used anywhere in the vehicle chassis to enhance occupant protection, Richardson said, including rocker panels, cross car beams, crush cans, bumpers and battery protection.
The component passed safety requirements, including the Insurance Institute for Highway Safety's shallow offset barrier test, during which the composite tunnel transfers the full force of the impact from the rocker panel to the transmission mount crossmember on the other side of the vehicle, he said.
"The beauty of composites is they can really carry a load through an entire event," Richardson added.
L&L developed the part with advice from Stellantis' assembly department to overmold nine different components into one complete part.
The partners developed a new computer simulation methodology using BASF's proprietary Ultrasim computer-aided engineering modeling software to capture the behavior of the pultruded structures to accurately capture the additional load after failure that a composite provides, Chris Korson, chassis market segment manager of performance materials at BASF, said in an Aug. 5 news release.
Computer simulations are a "game-changer" for energy management with composites, Richardson said.
CAE software also supports L&L's "no fear of failure" culture, he said.
"You never come up with the exact answer the first time. You have to continue to evolve and work through it. … We have to fail faster because that's where we learn," Richardson said.
"We have a product development process that encourages everybody that's still working on everyday products to run product development processes," Richardson said. "That spurs the innovation internally across the entire team instead of just … [leaving it] up to one group."
The partners also used Continuous Composite Systems pultrusion technology to combine the fiber-reinforced composite carrier with "highly engineered" sealants and adhesives and make "technology improvements to achieve an industry first in processing speeds as we doubled the typical profile pultrusion output," Richardson said in the release.
That efficient manufacturing process, with heightened processing speeds, brought the project its cost savings along with saved money in tooling from its rotary injection molding machine, Richardson added.
Since most of L&L's customers more frequently "bend and form steel," he said, the supplier hopes to educate engineers, "who already understand how to use metal," on different composite applications as it finds "[customers] that will be … adopters that can believe in composites."
The automotive industry's electrification goals have brought "an amazing amount of work" to L&L as it develops solutions for EV structures that are "different than what a combustion engine is," Richardson said. "There's a lot of learning going on with our structural inserts."
"We are always looking to improve on the design, function and efficiency of our vehicles," Brian Dwyer, chassis engineering manager at Stellantis, said in the release. "It's not easy to find a weight reduction solution that improves overall performance."