Focus on lighter, more fuel-efficient military vehicles
WASHINGTON — Alcoa Defense has applied innovative technology it developed for high-performance cars and the aerospace market in a project for the U.S. Army showcasing the ability of aluminum to make the next generation of military vehicle lighter, faster, stronger -– and more fuel efficient.
Alcoa has created an aluminum structure for the Army’s Fuel-Efficient Ground Vehicle Demonstrator (FED) that will make the vehicle up to 10 percent lighter than a comparably sized steel vehicle and reduce fuel consumption by 6-7 percent because the lighter vehicle frame enables a lighter engine, driveline and chassis. Alcoa supplied the FED’s aluminum chassis and cab structure with integral underbody armor protection to Ricardo Inc., the project’s lead engineering contractor. During the initial stages of design, Alcoa collaborated with Ricardo to determine which Alcoa solutions could best help achieve FED’s goals.
The FED project was launched by the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) in 2008 to develop a prototype vehicle that would showcase fuel efficient technologies, while maintaining the vehicle’s performance, payload capacity and protection of soldiers. If the Army, which operates the world’s largest fleet of ground vehicles, can improve fuel efficiency by just one percent, it will result in 6,000 fewer soldiers being put at risk by driving highly targeted fuel convoys in combat locations.
Lightweighting military vehicles via aluminum structures also enhances performance, which is why platforms that traditionally require maximum speed and agility, such as airplanes and sports cars, incorporate many aluminum technologies that originated with Alcoa. For instance, lighter aluminum vehicles can accelerate and brake faster than their heavier, steel-intensive counterparts. Additionally, aluminum is up to 50 percent lighter, yet provides more structural stiffness than steel.
“FED represents the first time we have been able to integrate a comprehensive suite of Alcoa’s lightweighting technologies into one vehicle,” said Alcoa Defense president Dave Dobson. “We are excited to have the opportunity to showcase all of our technologies for making vehicles lighter, faster and stronger in one groundbreaking platform.”
In addition to a welded aluminum spaceframe, other Alcoa innovations on the FED vehicle include:
An interchangeable aluminum blast and brush shield reduces curb weight. The strong aluminum blast shield that protects the underside of the vehicle can be switched to a thinner brush shield for use in non-combat environments to save on fuel. The blast shield was designed with Alcoa’s 2040 aluminum armor, a high-strength alloy that doesn’t fracture and resists blasts without failure or cracking. This is the first time that alloy 2040 has ever been used on a vehicle. Additionally, the blast shield is connected directly to the FED’s rocker panels beneath the doors and wheel wells. The rocker panels are load bearing, so integrating the blast shield directly into the vehicle structure gives it additional strength, which better protects the soldiers in the cab.
Instead of a conventional chassis design with frame rails on each side of the vehicle the FED cab is integrated directly into the front and rear chassis modules without frame rails. By eliminating the redundant frame rail components that typically connect the cab with the front and rear chassis modules, the weight of the vehicle is reduced while still maintaining its strength.
To increase survivability in combat environments, the FED vehicle features Alcoa’s CR56 aluminum alloy armor in both integral and appliqué (add-on) armor applications, providing excellent ballistic and blast performance protection.
To reduce weight and increase payload, new forged aluminum wheels were added to the FED vehicle. The wheels perform reliably in harsh conditions and provide substantial weight savings compared to conventional steel wheels. Aluminum wheels reduce tire rolling resistance by up to three percent compared to a comparably sized steel wheel, which results in one percent fuel savings, quicker acceleration and improved braking performance. Additionally, a lighter wheel assembly helps compensate for the weight of armor added to vehicles that were originally manufactured without armor. Finally, the lighter the suspension and wheels, the better the grip when tracking over rough terrain, which improves handling during hard acceleration or braking.
Pioneered by Alcoa on the Mine-Resistant Ambush-Protected All-Terrain Vehicle by Oshkosh, the FED will feature aluminum suspension components and mounting structure that can withstand harsh environments and difficult terrain. Forged aluminum suspension components deliver strength equivalent to steel at dramatically lower weight. One-piece aluminum forgings also eliminate welding, require minimal machining, easily bolt into place and reduce parts count significantly, which improves quality and streamlines the OEM manufacturing and supply chain process.
Many structural components of the FED vehicle are joined with Alcoa’s Bobtail fasteners, which deliver strong joints without compromising the integrity of the materials, which can occur with conventional welding techniques. In addition, they enhance long-term vehicle durability by maintaining joint strength when absorbing sudden impacts.
Alcoa also used friction stir welding, a specialized welding technique which improves quality by reducing weld-induced distortion, to join several aluminum alloys. Friction stir welding also allowed Alcoa to weld the thick aluminum plates that were integral to the vehicle’s blast shield. Alcoa has the expertise to help defense and commercial OEMs integrate aluminum components with high-quality friction-stir welds in their platforms.
With Alcoa’s all-aluminum cab and chassis structure serving as the vehicle’s foundation, Ricardo Inc. will integrate all other technologies and components into the vehicle, which is scheduled to debut at the Association of the United States Army (AUSA) Winter Symposium and Exposition in Ft. Lauderdale, Fla.
TARDEC embarked on the FED project to help achieve the Army’s long-term goal of reducing fuel consumption on the battlefield and its dependence on oil. The innovative solutions featured in the FED vehicle may become widely adopted by other military branches to enhance fuel efficiency in the next generation of tactical wheeled vehicles.
To demonstrate that FED’s aluminum technologies can be cost-effectively incorporated into future vehicle fleets, Alcoa built the prototype structure with the same cost-reduction considerations it applies to all OEM platforms. For instance, whenever possible, Alcoa uses aluminum product forms, such as forgings, extrusions and castings, that streamline production and decrease machining costs because their shapes very closely match the structures final form. To further reduce costs and streamline manufacturing for OEMs that typically specialize in steel structures, Alcoa also constructs aluminum subassemblies or full structures that OEMs can integrate into their vehicles. This support capability makes it much easier for OEMs to use the technologies featured in FED in production vehicles.
More information can be found at www.alcoa.com.
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