Description:
TECHNOLOGY AREA(S): Ground Sea
OBJECTIVE: Identify advanced braking concept(s) for heavy tactical vehicles (and trailers) that would meet or exceed current performance specifications relating to mobility, fuel economy, and safety, but with a smaller physical footprint (size/weight), and revolutionary advantages in maintenance and logistics support that will have a dramatic effect across the Marine Air-Ground Task Force (MAGTF).
DESCRIPTION: The Logistic Vehicle System Replacement (LVSR) is a family of vehicles, based on a common five-axle 10-wheel drive 10x10 chassis, that vary in individual configuration by mission requirements for the Marine Corps. LVSR is a purpose-designed military vehicle and there are currently three variants in service; a cargo, a wrecker and a tractor truck. The Medium Tactical Vehicle Replacement (MTVR) is a series of medium tactical cargo vehicles, based on a common chassis that vary by payload and mission requirements. The MTVR is a purpose-designed military vehicle, with nine variants (plus a sub-variant) as deliveries and development continues for the Marine Corps. Both the LVSR and MTVR have technical issues related to mobility, fuel economy and safety. Specifically, they are experiencing brake system problems across the fleet. There is significant corrosion of the drum and brake actuation mechanism from water and debris accumulating in the inner brake drum surface. This problem impacts safety, performance, operational availability, maintenance time, logistics delay time and money. Furthermore, drum brakes are heavy. They are made of mild to medium strength grey iron and the entire assembly (drum, pads, hardware, chambers) can weigh on order of 400lbs each. Under brake application, the brake pads expand out from the axle towards the drum surface longitudinally, inducing mechanical fade under severe heat. Their actuators as well as the entire assembly make drum brakes susceptible in tactical vehicle applications. The LVSR and MTVR have a 2mpg and 3.8mpg fuel consumption rate respectively with the fully burdened cost of fuel. Even a moderate increase in fuel efficiency can potentially save lives and millions of dollars. New brake technology on the current horizon appears promising. Innovative designs allow very high torque and are significantly lighter, smaller, and reliable while producing more brake force. These have significant performance advantages towards safety as well. New brake technology offers tactical advantages in that they can be inspected and maintained in the field, possibly without wheel removal and replacement. Such a feature would provide unprecedented mobility and agility to keep the Marines On-The-Move and not At-The-Halt. The technology provides game changing performance attributes that the Marine Corps may leverage for the LVSR and MTVR fleets and tactical brake applications that ultimately reduce total cost of ownership. This topic seeks to explore innovative, alternative, advanced brake designs to replace current brake systems used on the LVSR and MTVR. Of particular interest are concepts that: • reduce physical size and weight, • require less actuation force, • significantly lessen susceptibility to corrosion of the brake surface, friction linings and actuators, • can be both inspected and serviced in the field - preferably without wheel removal, and • can be a retrofit onto currently fielded MTVR and LVSR in an operational theater as well as in depot. Proposers are encouraged to address the benefits of tailorable design solutions that the brakes could potentially scale to work with specific vehicle axle configurations. The LVSR and MTVR are expected to operate in a variety of environments and terrains and the vehicles performance requirements are as follows: • The brakes need to be able to operate in the temperature range of -50°F to 125°F. • Proposed concepts should be mindful of the added technical challenges to maintaining a “mean miles between mission” hardware failure metric of no less than 2700 miles. • The brake will also need to be in conformance with Federal Motor Vehicle Safety Standards (FMVSS) 121, Society of Automotive Engineers (SAE) J1404, SAE J294, SAE J1587, SAE J1939, and SAE J1708.
PHASE I: Develop concepts for an alternate brake system by exploring the application of advanced design and engineering while meeting the required size and strength requirements for an LVSR and MTVR as discussed above. Demonstrate the feasibility of the concepts in meeting the Marine Corps needs and establish that the concept can be developed into a useful product for the Marine Corps. Feasibility will be established by design testing and analytical modeling, as appropriate, to facilitate the comparison of different concepts to include projected performance, reliability, and maintainability. Estimate hardware, installation, and maintenance costs. Provide a Phase II plan that identifies performance goals and key technical milestones, and addresses technical risks.
PHASE II: Based on the results of Phase I effort and the Phase II plan, develop a full-sized prototype with a scaled level of performance (initial testing will evaluate on-road performance only). The prototype brake will be evaluated to determine its capability in meeting reduced scale performance goals defined in the Phase II plan and the Marine Corps requirements for the LVSR and MTVR. System performance will be demonstrated through on-vehicle prototype evaluation and modeling or analytical methods as a means of validating the performance, reliability, and maintainability of the prototypes. Evaluation results will be used to refine the prototype into an initial design that will meet LVSR and MTVR requirements. Prepare a Phase III plan to transition the technology to LVSR and MTVR use.
PHASE III: Upon successful completion of Phase II, provide support to the Marine Corps in transitioning the technology for Marine Corps use. Develop a brake for evaluation and determine its effectiveness in an operationally relevant environment. Support the Marine Corps for test and validation to certify and quality the system for the Marine Corps use. The developed technology would also be directly applicable to the commercial trucking industry. Improvements in performance and reduction of maintenance costs would be very attractive to large commercial fleet operators.
REFERENCES:
1: "Federal Motor Vehicle Safety Standards and Regulations." U.S. Department of Transportation, National Highway Safety Administration – Safety Assurance; Standard No. 121. https://icsw.nhtsa.gov/cars/rules/import/FMVSS/
2: "Test Operations Procedure (TOP) 2-2-608 Braking, Wheeled Vehicles." US Army Developmental Test Command Test Operations Procedure, US Army Aberdeen Test Center, May 20th, 2008. http://www.dtic.mil/dtic/tr/fulltext/u2/a489156.pdf
3: "Service Brake Structural Integrity Requirements – Truck and Bus." Society of Automotive Engineers International, Standard J1404, Nov 2014 http://standards.sae.org/j1404_200705/
4: "Service Brake Structural Integrity Test Procedure – Vehicles over 4500kg (10,000 lbs) GVWR." Society of Automotive Engineers International, Standard J294, June 2016. http://standards.sae.org/j294_201506/
5: "Electronic Data Interchange Between Microcomputer Systems in Heavy-Duty Vehicle Applications." Society of Automotive Engineers International, Standard J1587, January 2013. http://standards.sae.org/j1587_201301/
6: "Serial Control and Communications Heavy Duty Vehicle Network – Top Level Document." Society of Automotive Engineers International, Standard J1939, August 2013. http://standards.sae.org/j1939_201308/
7: "Serial Data Communications between Microcomputer Systems in Heavy-Duty Vehicle Applications." Society of Automotive Engineers International, Standard J1708, September 2016. http://standards.sae.org/j1708_201609/
8: "Parts and Accessories Necessary for Safe Operation." Federal Motor Carrier Safety Regulations (FMCSR), Sections 393.40-393.52. https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&ty=HTML&h=L&mc=true&=PART&n=pt49.5.393
KEYWORDS: Tactical Truck; Weight Reduction; Braking; Improved Maintenance; MTVR; LVSR
