News 1998 Army Science and Technology Master Plan

P. Materials, Processes, and Structures

1. Scope

The Army’s materials, processes, and structures (MP&S) program provides enabling technologies that are used to construct every physical system or device that the Army uses. The MP&S program provides Army–unique technology solutions and options that will increase the level of lethality and survivability performance and improve mobility, transportability and durability while reducing the maintenance burden and life–cycle costs of all Army systems.

The materials subarea focuses on providing materials with the superior properties required for use in structural, optical, armor, and armament, chemical and biological (CB) warfare and laser protection, biomedical, and Army infrastructure applications. All classes of materials are included: metals, ceramics, polymers, composites of all types, coatings, energetic, semi– and super–conductor, and electromagnetic functional materials. Meeting the performance needs of future Army systems will require synthesis of new materials, modification of existing materials, design of property specific microstructures and composite architectures, and development of advanced modeling and characterization techniques for specific microstructures, properties, and both quasi–static and dynamic degradation and damage modes.

The materials processing subarea includes those technologies by which raw or precursor materials are transformed into affordable monolithic or engineered materials and/or components with the requisite properties and reliability for Army utilization. Included in the processing subarea are such technologies as casting, rolling, extrusion, cold and hot isostatic pressing, hot pressing, furnace sintering of metal or ceramic powders, laser sintering of titanium, polymerization, filament winding, composite processing and curing, joining, machining, and chemical vapor deposition. Also, lower substrate temperature coating processes are being developed, including ion beam assisted deposition (IBAD), pulsed laser deposition (PLD), and other surface modification technologies.

Process modeling and control and the development of new processing techniques for the manufacturing of multifunctional material systems will simultaneously improve quality and reduce costs of future Army materiel. Under the new paradigm of "intelligent processing," quantitative process models, AI/expert systems, embedded sensors, intentionally inhomogeneous compositional and microstructural gradients for localized property modification, and feedback/feedforward control systems are coupled so that processes can be adjusted in real time. Closely allied to "intelligent processing" are online nondestructive testing and inspection technologies, which enhance quality and durability.

The structures subarea is aimed at demonstrating generic structures based on advanced materials and processes that meet Army specific needs, such as structural elements for armored vehicles and helicopters, guns and ammunition, and missile/smart projectiles. Particular emphasis is on the development and modification of design tools and modeling for failure, fatigue, and life prediction analysis.

2. Rationale

All Army hardware critically depends on MP&S for its performance, affordability, and durability. To the maximum extent possible, the Army relies on improvements of existing MP&S capabilities in industry, academia, and the other services. However, the many unique Army requirements, such as thick–section ballistically efficient composite structures for combat vehicles, combat helicopter structures, CB and laser protective materials, antiarmor munitions, transparent and opaque armor materials, do not have commercial markets that support an adequate private sector R&D infrastructure. Further, there is no commercial analogue that superimposes both the severe environments and sustained high–stress use to which materials are subjected on the modern battlefield. Thus, a robust in–house MP&S technology generation program is essential to sustain the Army’s current and especially its future warfighting edge. A soldier–responsive in–house R&D combat operating environment (COE) with a critical mass of dedicated experts is essential to focus and manage the creation, evaluation, and transition of both external and internal MP&S technology advances to address Army specific requirements.

3. Technology Subareas

a. Materials

Goals and Timeframes

New materials with greatly improved properties and durability are being developed that enable major capability improvements for Army systems. For example, entirely new polymer matrix composite material concepts that are being developed for reducing armor weight by 35 to 45 percent will also dramatically improve ballistic performance and reduce overall systems costs. This weight reduction development will have a significant impact on increasing air deployment capability. Further opportunities arise from the multifunctional capabilities of composite material systems, whereby structural, ballistic, and signature reduction improvements can be incorporated simultaneously into one system.

Advanced ceramics are under development for both opaque and transparent armor ceramic applications as well as for missile guidance domes and windows. Transparent spinel ceramics, other glass–ceramics, and polymers are being developed to demonstrate superior ballistic properties for soldier systems application in FY99 under STO IV.P.05. Also, the characterization and evaluation of opaque ceramics under lateral and axial constraint are under investigation to improve their capability for interface defeat of high velocity impacting projectiles (see Figure IV–14). By FY04, advanced armor ceramics having improved penetration resistance with confinement will be demonstrated for larger scale projectiles at velocities above 2,000 meters per second (m/s). Opaque ultra light ballistically resistant personnel armor materials are being developed under STO IV.P.04 for FY99. Recent advances in converting highly ordered polymers into textile fibers with outstanding strength–to–weight ratios will lead to lighter weight body armor, helmets, and shelters without reducing ballistic protection (see Section IV–F). Computer–aided design (CAD) of the molecular structure of polymers will be utilized to develop improved transparent armor and controlled permeability barrier materials for protection against chemical and biological agents by FY98.

Figure IV-14. Interface Defeat of Long-Rod Projectiles by Constrained Armor Ceramics
Figure IV-14. Interface Defeat of Long-Rod Projectiles by Constrained Armor Ceramics
Click on the image to view enlarged version

Weldability and the evaluation of mechanical and ballistic properties of low–cost titanium alloys (with higher interstitial content) are being pursued for appreciable weight reductions over conventional aluminum and steel alloys for ground vehicle applications. Higher performance heavy alloys for penetrators and shaped charge warheads are essential to defeat advanced armor systems. The goals include a full–sized tungsten penetrator with equal performance to depleted uranium by FY03 and replacement of copper shaped charge liners by FY05. Issues related to the development of advanced warhead materials are discussed in Section IV–I. Improved ceramic thermal barrier coatings, wear resistant coatings, and monolithic and reinforced ceramics composites for rotorcraft and ground vehicle propulsion (see Sections IV–C and IV–S) will be demonstrated in the FY98–02 timeframe. Wear resistant coatings and advanced composite materials with tailored combinations of mechanical and physical properties for reducing weight and improving durability of both conventional armaments and electric guns will be demonstrated by FY98 (see Section IV–I).

Major Technical Challenges

While the field of materials science and engineering has made dramatic advances in materials performance, many formidable scientific and technological problems still exist. Of particular importance to the Army is the ability to transition the state–of–the–art knowledge base of composition-microstructure property parameters to models that predict the behavior of materials in such complex phenomena as ballistic penetration and defeat, detonation kinetics, environmental degradation, and chemical agent permeation. Specific technical challenges include:

Develop and validate models to predict the static and dynamic behavior of fiber/matrix interfaces for improved synthesis and performance of polymer and/or inorganic matrix composite structural materials.
Develop and validate predictive models for the environmental durability of monolithic and composite materials. Develop and validate improved models for the interactions of gases, vapors, and liquids with polymeric barrier materials.
Design opaque and transparent ceramics microstructures that will provide superior ballistic performance with improved mass and space efficiencies. Develop cost–efficient lightweight transparent armor ceramics and polymers for personnel and sensor protection.
Design tungsten or other heavy metal alloys/microstructures that will provide equal ballistic performance to depleted uranium, and improvements over copper shaped charge liners.
Develop high strength steels and titanium alloys with improved ballistic properties that also maintain toughness, weldability, affordability, and stress corrosion cracking resistance.
Develop improved materials for protection from agile laser threats for the individual soldier and direct view optics. Also, improved nonlinear optical materials for sensor protection devices.
Reduce wear and erosion in structural and functional materials for armament and vehicle components. Model and mitigate the micromechanical failure mechanisms in elastomeric materials for tank track application.

b. Processes

Goals and Timeframes

The MP&S program thrusts in processing S&T focus on those processes that are required to implement the incorporation of advanced materials in Army systems. Thick section composite processing presents unique challenges not encountered in traditionally thin structures. Process simulation models are being developed that couple the effects of thermochemical and thermomechanical interactions and incorporate micromechanical models to accommodate complex fiber/fabric architectures are required (see Figure IV–15). New technologies such as coinjection resin transfer molding provide improved properties while reducing manufacturing costs of multifunctional integrated armor systems under development. These will be transitioned to the Tank–Automotive Research, Development, and Engineering Center (TARDEC) during FY98.

Figure IV-15. Process Simulation Methodology for Thick Section Composite Structures
Figure IV-15. Process Simulation Methodology for Thick Section Composite Structures
Click on the image to view enlarged version

Improved process control methodologies including neural net feedback/feedforward capabilities, will be demonstrated in FY98–99 and will transition to the Composite Armored Vehicle (CAV) ATD and follow–on programs. Integration of the sensor mounted as roving thread (SMART) weave process into manufacturing systems is covered in Section IV–T. Processing thrusts to develop low–cost titanium alloys for lightweight armor and weapon systems such as howitzers, with enhanced air mobility, will be demonstrated by FY98. Lower temperature and lower cost ceramic processing approaches are being developed to improve the affordability and availability of advanced transparent and opaque armor ceramic materials. Properties and tape casting process optimization for recently developed high performance barium strontium titanate ferroelectric materials are being refined that will enable size, weight, and cost reductions for a new generation of microwave phased shifters at 35 GHz. This technology will transition to CECOM in FY05.

Major Technical Challenges

Much progress has been made in modeling single processes and process steps. However, the integration of real–time, noncontact, or online sensing (especially at the very high temperatures required in metal and ceramic processing) with adaptive control technology for the vast array of materials processes used by the Army is a formidable challenge. Specific challenges include:

Develop and validate knowledge–based models for consolidation synthesis, post–consolidation thermal or thermomechanical processing, and improved capability for joining or repair of polymers, ceramics, metals, and organic and inorganic matrix composites.
Develop opaque and transparent ceramic processing models for improved affordability and impact damage tolerance performance. Develop consolidation processing techniques for nano–size ceramic and metallic particulates.
Develop process–specific sensors and control systems.
Develop new materials processing or surface modification to achieve near or actual net shape components of complex geometry and variable composition and microstructure combinations to yield significantly improved tribological or structural performance in more affordable materials/design systems.

c. Structures

Goals and Timeframes

The structures portion of MP&S technology focuses on developing structures with a high level of structural integrity that are inspectable, analyzable, and survivable in the harsh combat environment. To be cost effective, the structural design must integrate advanced structural design concepts that are compatible with mass production manufacturing technologies. These structures can be man–rated or unmanned air or ground vehicles and hence must be designed to specific vibration and noise levels to maintain crew comfort and a low noise signature.

The technological efforts have led to improved methodologies for detecting and predicting the onset and growth of internal damage in composite structures. This has resulted in lighter weight, more durable structures. In the advanced concepts area, conceptual composite vehicle structures that integrate both ballistic protection and structural support are being evaluated (see Figure IV–16). Such integral composite structures offer significant improvements in weight and noise reduction, as well as the additional potential for the integration of other multifunctional attributes. Additionally, composite structures in rotating pulsed power systems (Figure IV–17) provide distinct weight and other design advantages. The application of smart materials to control sound transmission through a structure has been demonstrated on fuselage–like shell structures fabricated from composite materials. Reducing interior noise levels greatly improves crew comfort and reduces occupant fatigue levels.

Figure IV-16.

Figure IV-17

Major Technical Challenges

Design structurally efficient, cost–effective, and durable composite structures for Army unique ground and air vehicles as well as other structural applications, including troop support and ordnance.
Develop fracture mechanics methodologies, low–cycle fatigue, and stress analyses suited to meet Army structural needs.
Develop nondestructive evaluation (NDE) techniques and affordable in–situ sensors for identification and quantification of defects and anomalies in composite structures.

4. Roadmap of Technology Objectives

The roadmap of technology objectives for Materials, Processes, and Structures is shown in Table IV–32.

5. Linkages to Future Operational Capabilities

The influence of this technology area on TRADOC FOCs is summarized in Table IV–33.

Table IV–32.  Technical Objectives for Materials, Processes, and Structures

Technology Subarea

Near Term FY98–99

Mid Term FY00–04

Far Term FY05–13

Materials Armor ceramics evaluated in interface projectile defeat

Ultra–lightweight, ballistically–resistant materials

Low cost, 20 GHz ferroelectrics

Low cost titanium alloy transitioned to TACOM

Multiplane damage detection of composite laminates

Ceramic process/defects evaluated for interface defeat

Ceramic thermal barrier coating for Army propulsion

28–35 GHz materials database

Tungsten–based, long–rod kinetic–energy (KE) penetrators

25% cost reduction in organic composite structures

Confined armor ceramics transitioned to user

High temperature polymers (u400_C)

35 GHz materials for phased array antennas

Tungsten shaped charge liners

Thin film microwave materials

Processes Transparent armor prototype

Scaleup of Si diamond–like carbon (DLC) coatings

Laser processed titanium plate

Co–injection RTM of multifunctional integral armor

Organic (polymer) matrix composite (OMC) and carbon–carbon (C–C) composites for the Ballistic Missile Defense Organization (BMDO)

Transparent spinel scale up

Consolidation of metal and ceramic nanopowders

Continuous process for insensitive propellants

RTM processing with embedded sensors

Transparent, low–cost aluminum oxynitride (ALON)

Electron beam curing of large organic composites

Continuous process for insensitive explosives

Affordable rapid prototyping with inorganics

Structures Composite rotor blades

Energy absorbing structure

Constitutive behavior of rocket propellants at interior ballistic rates.

Lightweight, low–cost structural concepts

Demonstrate user defined composite structure

Multifunctional armor for active protection (AP), overhead, and mineblast

Pulsed power storage device

Case–bonded gun launched rocket motor designs

Composites with embedded actuators and active sound cancellation.

Controls and airframe for gun launched projectiles

Lightweight rail gun structures


Table IV–33.  Materials, Processes, and Structures Linkages to Future Operational Capabilities

Technology Subarea

Integrated and Branch/Functional Unique Future Operational Capabilities

Materials TR 97–021 Real–Time Target Acquisition, Identification, and Dissemination
TR 97–022 Mobility—Combat Mounted
TR 97–037 Combat Vehicle Propulsion
TR 97–040 Firepower Lethality
TR 97–043 Survivability—Materiel
TR 97–044 Survivability—Personnel
Processes TR 97–022 Mobility—Combat Mounted
TR 97–030 Sustainment Maintenance
TR 97–040 Firepower Lethality
TR 97–043 Survivability—Materiel
TR 97–044 Survivability—Personnel
TR 97–045 Camouflage, Concealment, and Deception
Structures TR 97–022 Mobility—Combat Mounted
TR 97–023 Mobility—Combat Dismounted
TR 97–035 Power Source and Accessories
TR 97–040 Firepower Lethality
TR 97–043 Survivability—Materiel

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