Altair Enlighten Award winner for Full Vehicle category: the 2019 Chevrolet Silverado. (image: General Motors)
Top mass-cutting innovations receive Altair Enlighten Awards
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Employing a mixed-material strategy that includes the latest advanced high-strength steels (AHSS) and shedding 450 lb (205 kg) compared to its predecessor are major reasons why the 2019 Chevrolet Silverado was chosen as the Full Vehicle category winner of the 6th annual Altair Enlighten Awards, presented by Altair and the Center for Automotive Research (CAR) at the Management Briefing Seminars (MBS) in Traverse City, Mich.
The Silverado was among six winners in four categories to be recognized for their mass-reduction achievements. In the Module category, BMW won with its 3D-printed metal convertible roof bracket used in the 2018 i8 roadster, a claimed industry first for a production series vehicle. The Enabling Technology category honored three innovations: Asahi Kasei’s brake pedal bracket for the Mazda MX-5 that was designed using glass-fiber-reinforced polyamide 66 (GFRP); Sika Automotive’s lightweight constrained layer material system for structure-borne noise damping; and United States Steel’s martensitic ultra-high strength steel (UHSS), Mart-Ten 1500, which was featured on the 2019 Silverado for structural elements such as the rocker inner.
New to the 2018 competition is the Future of Lightweighting category, which went to American Axle & Manufacturing (AAM) for its Quantum driveline architecture. This category was narrowed to six finalists by the judging panel, which consisted of international automotive experts from industry, academia and the engineering media (including the author, who edits SAE’s Truck & Off-Highway Engineering magazine), and the winner was determined by MBS attendees.
The six Altair Enlighten Award winners were selected from a field of 57 finalists—nearly double the total from last year’s competition.
“Nominations from OEMs, suppliers, materials technology companies, start-ups and academia demonstrate the tremendous and varied weight-reduction effort being achieved across the global automotive industry,” said judging chair Carla Bailo, President and CEO of CAR, and the current VP of Automotive sector for SAE International, in a release. “We were also thrilled at the response to the new Future of Lightweighting category introduced this year, which highlighted some highly innovative solutions holding great promise to advance fuel efficiency and automotive sustainability.”
Full Vehicle—Beating out three other full-vehicle finalists, the Silverado achieves its 450-lb overall weight savings via a multi-disciplinary optimization CAE approach, a higher percentage of UHSS, AHSS and high-strength low-alloy (HSLA) steel, along with new assembly methods, and aluminum closures. Disciplined part design resulted in the use of scalloped flanges and lightening holes.
Breakdown of a few of the vehicle-level mass reduction figures (crew cab):
• Cab structure: -35.6 kg (-78.5 lb)
• Aluminum plenum: -6.6 kg (-14.6 lb)
• Liquid applied sound deadener: -1.3 kg (-2.9 lb)
• Aluminum closures: -42.0 kg (-92.6 lb)
• Frame: -40 kg (-88.2 lb).
Various aspects of the 2019 Silverado have been detailed by Automotive Engineering since its reveal at the Detroit Auto Show in January, including GM’s “bombshell” announcement that the new Silverado will offer the first-ever 4-cylinder for a full-size pickup (https://www.sae.org/news/2018/05/gm-2.7-l-i-4-revealed). Weight-saving measures yield an engine that’s 80 lb (36 kg) lighter than GM’s less-powerful 4.3-L V6.
The Full-Vehicle runner-up was Mercedes-AMG for the aluminum-CFRP (carbon-fiber-reinforced plastic) hybrid body of its 2016 GT R sports car. Six composite applications for structural elements were implemented: carbon torque-tube, carbon fenders, carbon tunnel reinforcement, carbon roof, GFRP load-distribution plates, and carbon rods. The complete composite package offered a 12.3-kg (27.1-lb) mass reduction, or 33%, compared to the already-lightweight aluminum design.
Based on several parameters such as manufacturing volume, quality requirements, geometric and functional complexity, and economic restrictions, Mercedes-AMG engineers employed one of four different processes to achieve the best performance for each application: resin transfer molding, pultrusion, prepreg compression molding, and a Selective PrePreg Process by Multimatic.
Module—BMW topped 16 other finalists in the Module category, which focuses on vehicle systems, subsystems and components. The metal 3D-printed bracket (below) attaches the convertible roof cover to a spring-loaded hinge, enabling the roof to fold and unfold without the need for additional noise-reduction measures such as rubber dampers or a stronger (heavier) spring and drive. Produced with Selective Laser Melting (SLM) technology without needing any support structures, the bracket also marks the first time a topology-optimized design has been translated nearly 1:1 into a series production vehicle, BMW claims: “Thanks to 3D printing, the optimization result can be used almost directly.”
The component is 44% lighter and 10 times stiffer than the initially planned, but not sufficiently stiff, component made using injection molding from PA6GF30. The 3D-printed bracket also offers a cost benefit compared to a magnesium die-casting alternative.
Runner-up in the Module category was Faurecia for its Resonance Free Pipe (RFP), which contributes to vehicle mass reduction by eliminating the need for small silencers, or resonators. The RFP can reduce the weight of a light-duty vehicle’s exhaust system by 3 to 5 kg (6.6 to 11.0 lb), or an average of 15%.
Enabling Technology—Three technologies claimed the Enabling Technology prize, which focuses on technological advances that enable manufacturers to save weight. Asahi Kasei’s PA66/GF33 brake pedal bracket (below) for the Mazda MX-5 results in an 83% weight reduction compared to the baseline metal bracket. By using topology optimization technology, the new injection-molded design can be fixed at only two points, compared to six points for the initial model. As a result, the team could delete unnecessary parts from the sheet metal design.
Sika Automotive’s winning entry, a constrained layer material system (below), incorporates a newly developed damping material composition with much lower area weight and improved acoustic performance. Typical materials for structure-borne noise damping have an area weight of 5 kg/sqm, which was reduced by up to 80% in midsize sedans such as the BMW i8, Audi Q7, and Mercedes A-Class, when using Sika’s new material system.
U.S. Steel’s Mart-Ten 1500 UHSS for structural components, the third winner in this category, was recently introduced to the automotive market with ultimate tensile strengths exceeding 1,500 MPa. Advances in continuous annealing technology have enabled the Gigapascal strength to be achieved consistently and repeatedly in mass production to offer more than 10% in weight savings. The material, which has a minimum 3% elongation and a minimum bending ratio (radius/thickness) of 4, is suitable for frame rails, pillars and cross-car supports. Flex-N-Gate was the roll former for the Silverado application.
Future of Lightweighting—This new category, which received 25 entries, was introduced this year to recognize innovative ideas, processes, materials and technologies that have significant potential to support lightweighting initiatives but have yet to be leveraged on a production vehicle platform. The inaugural award-winner is AAM for its Quantum driveline architecture, which uses lightweight materials, hollow shafts and efficient structural shapes to achieve a 35% mass reduction in a light-duty pickup rear axle assembly (below).
Employing ball bearing subsystems that are integral with the gear components they support, the system enables a greater mounting accuracy and stiffness that increases the power density (torque per gear size). The design also allows for the first ever “completely net build” assembly in this product space, according to AAM. Net build is one of the key factors that offsets the cost of the lightweight materials used in the gear housings.
“It’s a rewarding experience each year to witness how simulation-driven design strategies, new materials and advanced manufacturing processes are advancing automotive lightweighting by offering new opportunities to innovate weight-efficient products from the start,” said Richard Yen, Altair's Senior Vice President of Global Automotive and Industry Verticals, at the ceremony.
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