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Harley-Davidson’s LiveWire electric motorcycle earned the Full Vehicle top honor in this year’s Altair Enlighten Awards. (H-D)

Altair honors lightweight advances

Harley-Davidson, Toyota, Mubea and Marelli recognized with the 2020 Altair Enlighten Award for their vehicle-lightweighting innovations.

Fitting for an industry that collectively is accelerating electric-vehicle launches, Harley-Davidson’s LiveWire electric motorcycle won the Full Vehicle category of the 8th annual Altair Enlighten Awards, the vehicle and component lightweighting competition conducted by Altair and the Center for Automotive Research. Winners were recognized on August 4 in conjunction with CAR’s virtual Management Briefing Seminars.

In the Module category, Toyota won for its new, one-piece resin seatback in the 2021 Sienna minivan’s folding third row, replacing a 15-piece steel frame. Mubea took top honors in the Enabling Technology category with its glass fiber-reinforced polymer (GFRP) tension leaf spring that offers weight savings of up to 75% compared to conventional designs.

The Future in Lightweighting winner was Marelli for its advanced sheet-compression-molded suspension steering knuckle made from chopped carbon fiber. This category is reserved for advanced technology that has not yet been employed on a commercial production platform. “This year we have seen trends in sustainability with electrification and a lot of mixed-material constructions, especially applying composites and simulation technologies,” Richard Yen, Altair senior vice president, said at the awards ceremony.

While the awards acknowledge the automotive industry’s best initiatives to reduce vehicle weight and meet emissions targets, they also consider other parameters such as cost reduction, improved performance, part count reduction and applicability to other vehicle programs. “Design optimization is critical for every new product in the automotive industry and lightweighting is a key component,” said Carla Bailo, president and CEO at CAR, adding that cost also plays a big role. “We have to look at maintaining cost, or with some of the award winners, actually reducing cost.”

Full Vehicle
By going electric with its LiveWire motorcycle, Harley-Davidson improved energy capacity by 90% while increasing the ratio of energy capacity to vehicle mass by 60%. The company said this initiative established mass and stiffness design and optimization practices for future motorcycle programs.

“We needed to add battery capacity to get more range and increase the motor size to get more power,” Glen Koval, general manager of engineering at Harley-Davidson, explained at the ceremony. To compensate, the engineering team “had to really dive in” to optimize weight elsewhere. “We were able to keep vehicle weight relatively neutral. Our chassis is the lightest chassis we’ve ever designed at Harley-Davidson, using aluminum composites,” he said.

Aluminum was chosen because of the stiffness requirements to handle forces coming in and out of turns, Koval explained. “But we did bring in composites around many of the other components that don’t require chassis stiffness – fenders, body panels, most of the brackets are of different composite materials.”

Runner-up: Nissan for its new 2020 Sentra global platform. Increased application of ultra-high-strength steel (UHSS) helped to dramatically improve safety and vehicle-dynamics performance without increasing weight.

The Toyota North American R&D team collaborated with engineers at supplier partner BASF on the design and execution of a two-occupant injection-molded seatback with no molded reinforcement for the 2021 Sienna’s third-row seat. A claimed industry-first, the free-standing resin seatback consolidated the previous design’s 15 components into one part with one injection, driving down costs by 15%, reducing mass by 30% and doubling safety performance.

“We can use that saved weight in other areas, such as adding new features like the built-in refrigerator,” said Todd Muck, senior principal engineer for body design, who led the lightweighting effort. Another major benefit is the reduced effort it takes to raise the folded third-row seats. “With the previous design, it would take more than 24 kg (53 lb) of force to raise the seat,” he said. “The new design requires less than 9 kg (19 lb) of force.”

Runner-up: ZF created the “first-to-market” heavy-duty electric park brake that offers a weight savings of 25 lb (11 kg) or more for large trucks and SUVs when compared to conventional drum-in-hat park brakes.

Enabling Technology
Mubea engineers developed the single-layer GFRP tension leaf spring using a scripted and automated workflow that begins with a parameterized spring model from which all spring parameters can be adapted. Its unique design substitutes the length-compensating shackles from attachment points with the characteristic rear shape of the spring. The GFRP spring is up to 75% lighter than a standard multi-layer steel spring. Other inherent benefits, according to Mubea general manager Ryan Hiligan, include improvements to ride comfort, NVH and warranty costs to the field.

Runner-up: DuPont’s BETASEAL X2500 structural adhesive quickly joins thermoplastic inner and outer liftgate panels to enable modular lightweight assembly. Magna thermoplastic liftgates bonded with BETASEAL X2500 have realized a 20-30% weight savings compared to welded steel designs.

Honorable mention: Mazda’s computer-aided engineering (CAE) multi-disciplinary design optimization (MDO) methodology was recognized for being a “top technology trend,” applying simulation-driven design and data analytics for product design.

Future of Lightweighting
Marelli’s Ride Dynamics team developed the new steering knuckle made of chopped carbon fiber using a high-volume, high-pressure Advanced Sheet Molding Compression (ASMC) process. The result of years of research, the composite part offers a 25% mass savings compared to the aluminum version used on the Jeep Compass and a 50% savings compared to the cast iron version. The composite material is said to be as strong as traditional carbon fiber and more resistant to cracking.

The Marelli team claims that combining chopped carbon fiber with ASMC allows complex structural parts to be produced in a one-shot, net-shape process, with cycle times suitable for automotive production. Prototypes have been developed using a 1500-ton press.

Runner-up: Nissan engineers developed an aluminum/short carbon fiber reinforced thermal plastic (CFRTP) bodyside panel using topology design, showing potential to cut weight by about 50% compared to conventional steel bodyside panels.

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