5. Materials Science
The overall objective of the materials science program is the elucidation of the fundamental relationships that link the composition, microstructure, defect structure, processing, and properties of materials. The work, although basic in nature, is focussed on those materials, material processes, and properties that improve the performance, increase the reliability, or reduce the cost of Army systems.
Research priorities are defined in the Material Science Investment Strategy Plan, which is prepared by the Army Materials Coordinating Group. This group is composed of scientists from ARO, participating RDECs, ARL directorates, and TRADOC. The plan outlines a strong multidisciplinary program in materials science that emphasizes research in five broad areas: manufacturing and processing of structural materials for Army vehicles and armaments, materials for armor and antiarmor, processing of functional (electronic, magnetic, and optical) materials, engineering of material surfaces, and nondestructive characterization of components for in service life assessment. Major themes are reflected in the discussions presented below.
b. Major Research Areas
The materials field is highly interdisciplinary, encompassing such diverse specialties as physical metallurgy, solidstate physics, chemistry, biology, penetration mechanics, surface science, and materials analysis. On the submicroscopic level, research is concerned with the manipulation of atoms and molecules and with the interactive forces that bind them. There is a strong emphasis on such topics as electronic and atomic structure, bonding character, and the many interactions of radiation and particles with condensed matter. At the microscopic level, the field is concerned with the effects of chemistry, microstructure, and phase transitions on the structural and functional properties of materials. At the macroscopic level, research is concerned with the continuum behavior of materials and composites. There are expanding opportunities for advancing the science of materials through continued integration and understanding of the interrelationships between the microscopic and macroscopic domains. This is reflected by the increasing integration of material modeling and numerical simulation into materials science.
New generations of materials with vastly improved properties are currently under development. Technology has now progressed to the point where it is possible to observe and manipulate materials at the atomic scale. This affords the opportunity to begin introducing much greater robustness into the design of materials and new possibilities for enhancing their performance. A growing interest of the Army is the design and fabrication of materials at submicron dimensions. New approaches to material synthesis based on self assembly of surfactants on surfaces, microcontact printing and micromolding, and flexible manufacturing approaches are under development. Examples of materials prepared by the microprinting process are shown in Figure V11. This research is laying the foundations for the development of new generations of materials that will bear scant resemblance to the rudimentary materials technology that the Army depends on today. For example, a new class of "smart" materials is under development that will be able to sense its environment and significantly alter its properties to adapt to changing conditions. Likewise, molecular recognition and selfassembly techniques, which mimic natural processes, are being investigated as a synthesis route to new classes of multifunctional supramolecular systems.
Figure V-11. Microprinting Process
Microprinting techniques have been developed for preparing patterned structures with submicron feature sizes.
c. Potential Military Benefits
Materials science research supports the entire Army materiel acquisition effort by ensuring that materials will exist that fully satisfy future mission requirements for improved firepower, mobility, armaments, communications, personnel protection, and logistics support. The emphasis is on developing new materials and processes that will significantly enhance materiel performance and reliability and reduce overall system costs. Major areas of impact include Army needs for individual soldier protection, armor/antiarmor, air and ground vehicles, bridging, shelters, communications, target acquisition, data processing, and power generation.
6. Electronics Research
Electronics is an enabling technology for all future Army systems for the digitized battlefield of Force XXI and AAN. In particular, electronics research provides the seminal knowledge to explore new systems and enhanced capabilities for radar and radiometry, communications, C2, fire control, electronic warfare, navigation, weapon guidance and seekers, and night vision devices. Army electronics research focuses on the generation of technology that will enable systems to function within the constraints imposed by the need for operation on small platforms such as the soldier, truck, armored vehicle, and helicopter used in highly mobile land warfare. This research provides the flow of ideas, concepts, and technology to the Armys developers to ensure the full integration of stateoftheart electronics capabilities into advanced new systems in a timely and affordable manner. To achieve this goal and to maintain technological superiority, emphasis is placed on the investigation of a spectrum of nearterm to farterm technologies. The research is reviewed, shared, transitioned and transferred through the Reliance Electronics Planning Group process, the technology area plans, TARA, and the Electronics Coordinating Group (ECOG) activities.
b. Major Research Areas
To satisfy the projected requirements, Army electronics research emphasize three broad needs:
Solidstate and optical electronics with emphasis on ultrafast (terahertz switching speeds), ultradense electronics, and optoelectronic components.
Information electronics with focus on systems for operation in adverse environments, designed to lighten, simplify, and reduce power consumption (low power electronics); communication and radar systems operating at millimeterwave (MMW) through terahertz spectral region, and communications systems and networks and information processing for the digital battlefield.
Electromagnetics with emphasis placed on conformal antennas, MMW systems, and systems exploiting optical MMW interactions.
SolidState and Optical Electronics
Solidstate and optical electronics research in the near term includes advanced semiconductor devices supporting AAN applications, quasioptical techniques for advanced millimeter and subMMW systems, lowpower electronics, advanced IR sensor concepts, short wavelength lasers, and related materials issues. In the long term, electronics research must provide for novel, robust, reliable multifunctional ultrafast/ultradense electronics, and optoelectronic components and architectures. By designing devices based on new physical principles of operation, expanded functionality, greater packing density and higher speed can be achieved. Highresolution, highsensitivity, multicolor IR imaging arrays are required for target acquisition, recognition, and identification. Research thrusts include advanced materials, novel device structures, and appropriate system architectures. Ultrafast signal processing computing will require advances in light emitters. New system architectures are needed for increased data storage and efficient optical processing. As shown in Figure V12, a key element in solidstate and optical electronics research is atomiclevel feature control to provide devices that will meet the Armys future technology needs in device integration and information capacity.
Figure V-12. Electronics Research
Information electronics research is driven by the profound growth of battlefield information sources and the complexity and need to process and communicate that information in near real time for the digital battlefield concepts. Force XXI and AAN operational concepts call for a highly mobile force whose success is dependent on reliable voice, data, and video communications on the move and information with the minimum latency and varying quality of service requirements to ensure quick decisions and synchronous operations. Research is conducted in network management, network protocols and architectures, message routing including flow and congestion control, forwarding algorithms, advanced switching technology and interfacing, and integration of heterogeneous networks. Methods for the design of large, distributed, mobile spreadspectrum packet radio network architectures, protocols, routing, and control are investigated. The use of adaptive array antennas in networks to provide spatial reuse of limited spectrum, to increase network throughput capability, to increase interference and jamming resistance, and to lower transmit power requirements is investigated. Information fusion includes both sensor and data fusion techniques. It encompasses a number of scientific disciplines including signal, image, and speech processing; decision theory; distributed heterogeneous databases; and intelligent systems. It allows the improvement of accuracy and reliability of information, reduces the quantity and confusion of data, and provides realtime tactical command and control information assessment capability.
Electromagnetics research focuses on issues unique to Army needs such as circuit integration, antennas, and propagation that will enable Army exploitation of the terahertz, MMW, and highfrequency microwave portion of the spectrum for communications and radar and seeker systems for the digitized battlefield. Powercombining techniques such as quasioptics are critical in enabling moderate or high power MMW systems with the advantages of solidstate electronics. Optical control of microwave and millimeter circuits provides the opportunity for low weight, lowcost control of antenna arrays. Novel concepts for high efficiency, lowloss antennas and antenna arrays are of importance, including active antennas.
c. Potential Military Benefits
A key element in electronics research is atomiclevel feature control to provide devices that will meet the Armys future technology needs in device integration and information capacity. Enhanced performance and functionality of future electronics will lead to faster, more portable, and more reliable systems for target identification; intelligent systems for better command and control of fire support missions; miniaturized computers and displays with improved processing capability; data fusion of multidomain, compact, smart sensor suites; enhanced timing and location systems for autonomous weapons; optimized manmachine interface; ultrafast information processing in extremely small, massively parallel processors; highdata rate photonic communications; and ultrasmall integrated multifunctional sensors for the soldier. Realtime signal processing is critical to communications, adaptive array antennas, and signal intercept as well as image analysis, target acquisition, and information fusion. Signal and information processing are used in the implementation of image, radar, speech, antenna, and communication processing systems for applications in target detection, identification and tracking; guidance and control; fire control; and communication. Research in fast, highresolution, null and beamsteering and compact adaptive antennas will provide lowsignature communications and improved signal intercept capability.
7. Mechanical Sciences
The Armys reliance on mobile systems to perform its mission requires a major research effort in the mechanical sciences to provide the technology base that will enable the development of vehicles and their armaments with significantly advanced capabilities to meet the requirements of the AAN. The Army Mechanics Coordinating Group (MECOG) has developed a strategy for focusing the Armys future research programs in the mechanical sciences on the most opportune and important areas. The strategy takes advantage of the reliance process with the Navy and Air Force and is peer reviewed at the annual DDR&E TARA.
b. Major Research Areas
The MECOG developed the appropriate research thrusts and assigned priorities, while regularly coordinating inhouse and extramural research efforts in the four major fields of the mechanical sciences that are critical to Army interests:
Structures and dynamics
Structures and Dynamics
In the area of structures and dynamics, the research topic areas are structural dynamics and simulation and air vehicle dynamics. The higher priority research thrusts in structural dynamics and simulation are ground vehicle and multibody dynamics, structural damping, and smart structures and active controls. For air vehicle dynamics, the higher priority research thrusts are integrated aeromechanics analysis, rotorcraft numerical analysis, helicopter blade loads and dynamics, and projectile aeroelasticity. Multidisciplinary research on advanced active control of coupled rotorcraft vibration and aeroacoustics offers a significant potential reduction in rotorcraft vibration and acoustic radiation for the AAN (see Figure V13).
Figure V-13. Passive/Active Damping Control for for Rotorcraft Systems
In the area of solid mechanics, the research topic areas are the mechanical behavior of materials, the integrity and reliability of structures, and tribology. The classes of materials of interest are functional gradient materials and heterogeneous materials. In mechanical behavior, the higher priority research thrusts are material responses in the state of nonequilibrium or transient states as in impact and penetration mechanics and damage initiation/propagation. Within this thrust is a special basic research program on smart resilient structures involving novel material concepts, material behavior, responsive mechanisms, and analytical tools that provide the fundamental underpinnings for a technologytoengineering development program for responsive armor concepts needed for AAN (see illustration). Additionally, the mechanical response under coupled effects of electric, magnetic, and thermal fields is of great interest. The research in the area of integrity and reliability of structures focuses on damage tolerance, damage control, and life prediction. In the area of tribology, dynamic friction, lubrication, and surface topology in low heat rejection environments are emphasized.
For fluid dynamics, the research areas are unsteady aerodynamics, aeroacoustics, and vortex dominated flows. The higher priority research thrusts in unsteady aerodynamics are dynamic stall/unsteady separation, maneuvering missiles/projectiles, and rotating stall and surge in turbomachinery. In aeroacoustics, the research thrusts are on helicopter blade noise generation, propagation, and control; and in vortex dominated flows, they are on rotorcraft wakes and interactional aerodynamics.
Combustion and Propulsion
For combustion and propulsion, the research topic areas are small gas turbine engine propulsion technology, reciprocating engine technology, solid gun propulsion, liquid gun propulsion, and novel gun propulsion. The higher priority research thrusts in small gas turbine engine propulsion are in critical combustion processes, enhanced optimization, and integration of miniature sensors and active controls. For reciprocating engine technology, the higher priority research thrusts are in ultralow heat rejection environments, enhanced air utilization, and cold start phenomena. For solid gun propulsion, the major thrusts are in ignition and combustion dynamics and high performance solid propellant charge concepts. For liquid gun propulsion, they are in atomization and spray combustion, ignition, and combustion mechanics and instability, hazards, and vulnerability. The higher priority thrusts in novel gun propulsion are electrothermalchemical (ETC) propulsion, active control mechanisms, and novel ignition mechanisms.
c. Potential Military Benefits
Research supported in the mechanical sciences provides the necessary tools to enable prediction, design, simulation, and assessment of future Army air/ground vehicles, their power plants, and armament systems, which results in increased performance, reliability, sustainment, and mobility. In particular, advanced, higher performance rotorcraft and vehicle gas turbine engines, stable weapon system platforms, accurate supply and weaponontarget delivery capabilities, resilient structures for heavy/light fighting vehicles, vehicle structural reliability and survivability, more energetic and reliable gun propellants, advanced electromagnetic gun propulsion systems, high power density diesel engines, weapon failure analysis/prediction, and multibody vehicle simulation capabilities, for example, can be expected from the Army research program. Mechanical sciences have a significant impact on five technology areas (Chapter IV): aerospace propulsion and power, air and space vehicles, individual survivability and sustainability, conventional weapons, and ground vehicles.
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