Use of Lightweight Materials in 21st Century Army Trucks (2003)

The U.S. Army has approximately 250,000 light, medium, and heavy trucks and 110,000 trailers in service at any given time. These trucks and trailers represent the logistical backbone of military operations.¹ The future Army truck fleet must meet the requirements of the Army’s envisioned Objective Force, including the requirements related to deployability, transportability, and mobility. These requirements mandate that Army trucks consume less fuel, undergo significant weight reduction, have a reduced logistics footprint, and need less maintenance while maintaining or increasing payload capacity and other performance criteria.

The use of lightweight² materials has the potential to help the Army meet its goals by reducing vehicle weight. The reduction of vehicle weight in itself would increase the ability of the Army to transport trucks and could result in reduced fuel consumption. In addition, some lightweight materials offer the potential for improved corrosion resistance, which would decrease the need for maintenance. The increased fuel efficiency that can result from the use of lightweight materials has additional benefits. Reduced fuel consumption would result in a reduced logistics footprint because less equipment and fewer personnel would be required to support a unit in the field. The true cost of fuel, including delivery, for the Army in normal times is approximately $13 per gallon. This increases to between $100 and $400 per gallon for delivery to war zones with no established fuel lines, roads, or infrastructure.³ The military vehicle multiplier for weight savings is therefore several times that of civilian vehicles.

The Committee on Lightweight Materials for 21st Century Army Trucks was asked to identify research and technology development opportunities

related to the introduction of new lightweight structural materials for light, medium, and heavy Army trucks. To address these objectives, the committee was asked to perform the following tasks: investigate materials, processes, and structural concepts that will be candidates for advanced truck applications for the Army; review the state of the art in lightweight structural materials and low-cost processing technology for automotive and truck applications, including advanced steels, wrought and cast aluminum, magnesium, titanium monolithic alloys, polymer matrix composites, and metal matrix composites; identify critical properties, design issues, maintenance issues, potential failure mechanisms, and end-of-life disposal or recycling processes for advanced materials and processes; recommend research and development opportunities and programs to evaluate and develop new advanced materials, processes, and structural concepts for advanced Army truck applications; and recommend methods for the U.S. Army Tank-automotive and Armaments Command (TACOM) to coordinate its advanced materials research efforts with industry and other federal agencies.

The structural applications considered in this report are divided into three categories: the frame running the length of the vehicle, to which the engine, drivetrain, suspension, and truck bed are all attached; the secondary structural elements, or vehicle parts that carry passengers and cargo, such as the cab and cargo bed; and the structural drivetrain, including driveshafts, suspension, steering mechanism, and braking components.

Time frames in the report are operationally defined as follows:

• Short term: referring to improved materials choices that can be substituted for existing materials in existing truck systems. This category does not include any fundamental redesign of the truck or its subsystems. Care must be exercised in making such changes because any materials substitution can alter the vehicle’s response to terrain changes and its ability to perform certain functions.

• Medium term: referring to a new design or significant rebuilding of a proven truck platform that represents an opportunity for more aggressive materials substitutions. Such an instance might involve the use of a modestly

different architecture or different joining methods. For example, the replacement of a truck’s steel frame rails with hydroformed tubes would require changes in several other design aspects and would thereby open up opportunities for materials substitutions.

• Long term: referring to changes in the present truck paradigm that would permit the use of radically different materials. In the future, truck architecture may become modular, with power plants providing electric power to driven axle or bed modules. This would eliminate the need for driveshafts and fundamentally change frame configurations.

The committee’s conclusions regarding opportunities for materials research and development are summarized in Table ES-1. For the short and medium term, advanced galvanized steel alloys combined with selective, justified application of other advanced materials should meet most of the Army’s light vehicle needs. A variety of steels in flat and plate forms are likely to remain the material of choice in the heavy truck categories. Additionally, for the short term, a number of commercially available materials and technologies can be used for Army trucks, including high-strength and stainless steels, aluminum and magnesium alloys, and metal matrix composites (MMCs). Manufacturing processes available today include superplastic forming, castings of aluminum and magnesium alloys, and the use of tailor-welded stamping/forging blanks.

For the medium term, materials such as dual-phase and ultrahigh-carbon steels, aluminum 2519, magnesium, MMCs, and polymer matrix composites (PMCs) are candidates. Finally, for long-term applications, Army trucks can benefit from investment in titanium, smart materials, and additive metal process technologies. Investments in advanced materials, including nonferrous alloys, composites, and coatings, that offer superior performance and reduced operations, maintenance, and service costs would serve the longer-term, mission-specific needs of future tactical trucks and combat programs. In such cases, the need for condition-based vehicle health monitoring cannot be overemphasized.

RECOMMENDATION. THE ARMY SHOULD PURSUE THE USE OF LIGHTWEIGHT STRUCTURAL MATERIALS IN ITS TRUCK FLEET, AS FOLLOWS:

• The Army should follow the guidance in the table "Summary of Opportunities for New Materials, Applications, and Research," in this report.

• Research programs should be funded to develop the technologies listed in the table as medium- and long-term opportunities, and these programs should include system integration, development testing, and field testing.

• The Army should support the development of databases of the properties of these materials as well as the development of models for processing lightweight materials and for predicting the performance of components manufactured using these materials.

The use of new materials in Army trucks will have consequences for vehicle assembly, repair, and disposal. When assembling new vehicles or recapitalizing older vehicles, it will be necessary to ensure that galvanic isolation exists between parts made from different materials. The inspection, maintenance, and repair procedures for vehicles with such parts will become increasingly complex. End-of-life disposal and recycling processes will also change.

RECOMMENDATION. THE ARMY SHOULD INSTITUTE A MECHANISM FOR ENSURING THAT DIFFERENT TYPES OF MATERIALS ARE TRACKED DURING REPAIR AND DISPOSAL.

One such mechanism might be a color code or a numbering code that provided each alloy with its own identification. A coding system might clearly indicate to those making field repairs where galvanic corrosion may occur and where it is vital to provide galvanic isolation. (As an example, if all steel parts were one color and all parts made of a different metal were another color, it would be obvious which parts needed to be isolated.)

As different materials are increasingly used on Army vehicles, repair and replacement procedures will become more complicated. For example, composites are now used selectively in Army trucks, and repair procedures for these materials are not generally known and are very different from those for metallic materials. Maintenance training will be required for each new generation of vehicles. In addition, as some parts are changed during recapitalization programs, maintenance and repair manuals will need to be continuously updated. Computerization of future depot maintenance manuals would aid in their being kept current for purposes of repair. Vehicle original equipment manufacturers (OEMs) might be required to maintain these manuals, as well as information on common parts failures, on their Web sites.

Barriers to the implementation of lightweight materials technologies in Army trucks include organizational risk-aversion, few design cycles per product, and low production volumes. Means of promoting new technologies were identified, however. First, the Army procurement process could be improved with requirements for fuel efficiency and the use of life-cycle assessment and best-value procurement. Second, maintenance systems could be improved through design for reduced maintenance, systematic replacement of older trucks, and the use of alternative ownership strategies. Third, methods to reduce the cost of new technologies could be used—for example, modular design, the use of common systems and components, and standardization with commercial parts. Fourth, the use of alternative power systems could result in new truck paradigms that enable the insertion of radically different materials. Finally, commercial technologies could be leveraged through the Army's participation in existing collaborative programs. The following three recommendations address enabling technology insertion.

The Army truck fleet continues to degrade faster than it can be upgraded through new acquisitions, forcing the Army to use recapitalization techniques

simply to maintain the fleet size and effectiveness ratio.¹ While recapitalization permits the introduction of improved components such as the engine, improvements in overall vehicle configuration and structural architecture or the introduction of new lightweight materials are not feasible. New brigade requirements have created pressure to accelerate the introduction of lightweight materials into the truck fleet. In addition, the Revolution in Military Logistics (RML) initiative requires a 75 percent reduction in vehicle fuel consumption.² This initiative will most certainly require the aggressive application of lightweight materials.

The initial application of lightweight materials may increase the acquisition cost of a new truck, although the use of these materials may reduce life-cycle costs through enhanced corrosion resistance and reduced energy consumption. Although operations and support costs over the life of an Army truck can be as high as or higher than the initial acquisition cost, the acquisition cost continues to create a constraint when limited budgets are applied at the individual platform level. Moreover, for fear of not winning a contract, major suppliers are reluctant to risk using new technologies that raise the initial cost and/or add risk to the development process.

RECOMMENDATION. THE ARMY SHOULD DEVELOP A LONG-RANGE, FLEET-LEVEL PORTFOLIO STRATEGY THAT ESTABLISHES A SCHEDULE FOR TRUCK ACQUISITION, REMANUFACTURE, AND REPLACEMENT.

Although contingent on future funding, the plan would establish priorities for vehicle replacement with specific requirements for performance, including vehicle weight and fuel consumption for each type of vehicle. In order to reduce the technology development cost burden typically placed on an individual vehicle program, the strategy should also establish a broad technology development program plan. The technology development program should be based on a budget process that prioritizes new technology

development. The program should establish concept development activities leading to the fabrication of prototype vehicle demonstrators. In order to leverage resources outside the Army, the technology program should involve vehicle integrators, material and component suppliers, other branches of the Department of Defense, other government agencies, and any other key sources of technology. The accomplishments of existing government programs should be leveraged to the greatest extent possible.

The most effective way for the Army to influence the cost and performance of future truck designs is through the procurement process.

RECOMMENDATION. THE ARMY SHOULD MODIFY ITS BID SOLICITATION AND PROCUREMENT PROCESSES TO STIMULATE AND REINFORCE DESIRED REACTIONS, INCLUDING:

• The Army should clearly define the performance attributes that are important in its use of trucks. For example, if reduction of the logistical footprint is important, this attribute and its method of measure must be defined; if the total cost of ownership or life-cycle costs are important, these attributes should be defined. The bidding process should be structured to reward improvements in these performance attributes.

• The Army should provide minimum values or, preferably, scaled values for each performance attribute. For example, the value to the Army of reducing the logistical footprint or increasing fuel economy should be indicated.

• In selecting the winner of a competition, the Army should make certain that all performance attributes, including specifically the cost of ownership, are given their appropriate weighting in the decision.

• The Army should develop and adopt a consistent life-cycle costing methodology for evaluating alternative technologies. At a minimum, energy costs, maintenance costs, and end-of-life costs should be incorporated into this methodology. It should be emphasized in the request for proposals that life-cycle cost will be heavily weighted in the selection decision.

• Life-cycle costs should be extended to implement best-value procurement practices. The value of all performance attributes should be quantified and these metrics used to select the best-value truck to meet the Army’s needs.

• The Army should review and revise its needs regularly. The description of an ideal truck varies across time, geography, and need for use. The procurement process must be flexible and responsive to these changing demands.

Army trucks are kept in service far beyond their economically useful life, resulting in increased operations and support costs and decreased performance. The effectiveness ratio of the total Army tactical wheeled vehicle fleet was recently calculated to be about 0.63 (compared with 1.0 for a new fleet).³ Effectively, eight existing trucks are required to do the work of five new ones. In addition, the annual total operating and maintenance (O&M) costs for the Army truck fleet is about $1.5 billion, or more than $6,000 per truck. These costs are increasing at a rate of about $30 million per year, while the fleet size is being reduced from about 250,000 to about 225,000 trucks.⁴ Other data indicate that a large fraction of these costs are for corrosion repair. The economically useful life of a truck has recently been estimated to be about 13 to 16 years, at which point the effectiveness ratio is reduced to 0.5.⁵ Retirement and/or replacement should be considered at this age.

RECOMMENDATION. THE ARMY SHOULD ESTABLISH A MECHANISM FOR RETIRING OLDER TRUCKS AND FOR REPLACING TRUCKS IN POOR CONDITION WHEN THE AVERAGE YEARLY MAINTENANCE COST BECOMES PROHIBITIVELY HIGH.

A centralized tracking system might be used to record the present position of every truck in the fleet and ensure that trucks are retired and/or replaced on a regular basis. (Both Federal Express and United Parcel Service use such tracking systems for their trucks.) Such a system might also be used to select trucks for participation in recapitalization programs. Currently, the age and condition of Army trucks sent to such programs varies widely.⁶ Data on repairs and parts failure could be shared with manufacturers in order to facilitate design improvements. A more standardized system for the replacement of damaged trucks would promote the introduction of new materials and technologies into the truck fleet.

The committee was asked to recommend methods for TACOM to coordinate its advanced materials research efforts with industry and other federal agencies. The following recommendation addresses this issue.

The unique duty cycles and mission profiles of Army trucks constitute a special defense requirement. To respond to this requirement, the Army must take the lead in driving investments in new materials that have the potential to deliver competitive advantage in the logistics arena, supporting warfighters and combat equipment. At the same time, the Army can more actively leverage new materials and manufacturing technologies from the private and academic sectors by investing directly in research and development programs that lead to proof-of-concept demonstrations. The Army’s Small Business Innovative Research (SBIR) program is to be complimented for past accomplishments in this area; it should be kept well funded and targeted to the lightweight trucks initiative in order to encourage high-quality material and manufacturing innovations from academia and industry.

RECOMMENDATION. THE ARMY SHOULD LEVERAGE NEW COMMERCIAL MATERIALS AND MANUFACTURING TECHNOLOGIES TO ACCOMPLISH ITS GOALS OF IMPROVED MOBILITY, DURABILITY, AND FUEL EFFICIENCY IN NEW TACTICAL TRUCKS. TO ACCELERATE TECHNOLOGY TRANSITION, THE ARMY SHOULD PARTICIPATE IN COLLABORATIVE PROGRAMS WITH ADVANCED MATERIALS INDUSTRY CONSORTIA.

Effective leveraging can allow the Army to evaluate the technical feasibility of new materials and technologies. Pilot demonstrations of new materials and technologies in Army applications would also increase the knowledge and capabilities of the supplier base.

Additional leveraging opportunities for the Army exist in the form of industry-government programs sponsored by the Department of Energy and the Department of Commerce that have identified advanced materials for application development. The emphasis of participants from the commercial automotive industry on the affordability of new materials, such as titanium, magnesium, and polymer matrix composites, should greatly facilitate prudent investment decisions by the Army. By working more closely with university centers of excellence, the Army can identify new enabling technologies in lightweight materials and in sensing and vehicle health monitoring, and it can also fund demonstration projects. The early involvement of key stakeholders—including suppliers, maintenance personnel, and end users—in decisions regarding new materials is essential.