PDF | On Dec 30, , Ghareeb N and others published Smart Materials and Structures: State of the Art and Applications. Smart structures or smart materials systems are those which incorporate actuators and sensors that highly integrate into the structures and have. Bookreviews Smart materials and structures page M.V. Gandhi In particular, there is no mention of the use of optical fibres in combination with.
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Smart materials can change their physical properties in response to a of smart materials and structures, together with its current status and. A smart structure is a system containing multifunctional parts that can perform sensing, control, and actuation; it is a primitive analogue of a biological body. An introduction to smart materials and structures. B S Thompson, M V Gandhi and S Kasiviswanathan*. Abstract - This paper presents an exposition on the.
The sensors serve as a data col- Research Center, are looking into smart paints which lector as well as a wireless transmitter. Optical fibers which change in light trans- 3. Reliability and safety of structures using stability- mission due to stress are useful sensors.
They can be based hybrid controls, Professor B. Spencer embedded in concrete or attached to existing structures.
University of Notre Dame NSF-supported researchers at Rutgers University studied optical fiber sensor systems for on-line and real-time MR fluid dampers are one of the most promising monitoring of critical components of structural systems smart damping intelligent isolation systems according to such as bridges for detection and warning of imminent Professor B.
Spencer, Jr, due to proven technology— structural systems failure.
NSF grantees at Brown Uni- reliable and robust; low cost; insensitivity to tempera- versity and the University of Rhode Island investigated ture; low power; and scalable to full-scale civil engineer- the fundamentals and dynamics of embedded optical ing applications. Japanese researchers recently dampers in suppressing earthquake excitation in the lab- developed glass and carbon fiber reinforced concrete oratory.
Under NSF 3. Flexible wings for uninhabited air vehicles, P. University of Florida researchers at the University of California—Berkeley recently completed a study of the application of ER Ifju and colleagues are conducting research on design fluids for the vibration control of structures.
Courtesy of the late W. Courtesy of B. Spencer, Notre Dame University. There is tional lifting body paradigm. The flexible wing design currently a trend toward thicker materials of the order consists of a carbon fiber skeleton and a latex rubber of hundreds of micrometers in MEMS because a larger skin with a thin under-cambered shape based on those aspect ratio is needed for a mechanical device to be able of biological counterparts.
The flight characteristics of to transmit usable forces and torques. The mechanical the flexible wings have many superior qualities, adapting testing techniques are being extended to MEMS.
The air frame and wings of the aircraft are 3. Passive and active damping control for large made from carbon fiber.
These micro aerial vehicles civil structures, N. Wereley University of MAVs have been configured to optimize stability and Maryland flight performance. The control surfaces elevons are mounted under the wings so that they are continuously The objective of the research activities is to augment washed by the propeller. This allows the aircraft to be damping in large civil structures applications via both controlled, even when the airspeed is low.
Separating the passive and active means, to reduce structural response. A good RC sis, and experimental demonstration of passive, semi- pilot can hover the MAV and use the elevons as thrust active, and active structural damping control for civil directors. The MAV is also capable of stable flight structures using smart materials and structures tech- between 10 mph and 40 or 50 mph.
It can perform loops nology.
The research includes consideration of stability and barrel rolls. Damping strategies are being tested on 3. Mechanical testing and microstructural studies of dynamically scaled three-story civil structures building MEMS materials, Professors Sharpe and Hemker models using dampers such as depicted in Fig.
Johns Hopkins University. Design, modeling, and development of active New test methods have been developed to measure aperture antennas, G.
While engin- eers today are able to design MEMS and predict their The primary goal of this work is the development of overall response, they cannot yet optimize the design to a novel class of aperture antennas capable of variable predict the allowable load and life of a component directivity beam steering and power density variable because the mechanical properties of the material are not focusing or beam shaping.
The actuation for these available. This research is attempting to measure and antennas is employed using a distinct mechanism. The provide such data. Furthermore, they are performing mechanism employs polyvinylidene fluoride PVDF comprehensive microstructural studies of MEMS film bonded to a lightweight metalized mylar structure. Since the film is piezoelectric, any electrical voltage drop across the film will cause the film to lengthen in its stretch direction. The resulting lateral deflection from a length change causes the production of a moment which causes the antenna surface deflection.
This is illustrated in Fig. Ultra-precision shape-controlled smart structures, J. Main University of Kentucky Engineering systems that require ultra-precision con- trol of positions and shapes often use active materials as extremely precise actuators. Many active materials respond to applied electric fields, which are conven- tionally applied by distributed electrodes. In this investi- gation active material actuator technology is combined with an electron gun charge deposition system and the Fig.
Palm-sized micro aerial vehicle. Courtesy of P. Ifju, Univer- characteristics of the resulting shape and position control sity of Florida. The electron gun approach permits A.
Lower plots show displacement left and acceleration right responses to A no control, B skyhook controller, and C continuous sliding mode controller. Courtesy of N. Wereley, University of Maryland.
Use of discrete high deflection piezoelectric picomotor actuators to produce deformation for an active aperture antenna, allowing expanded ground coverage through beam steering. Courtesy of G. Washington, The Ohio State University. Actuation sys- active material, thus making it possible to command tems such as this have the potential to be controllable at strains and displacements at extremely precise locations the nanometer level.
The overall technical objec- 3. Hybrid magnetostrictive composite material for tive is the development of a thorough understanding of active control, G. Carman University of California electron gun shape control of piezoelectric materials, at Los Angeles including possible shape-control limits, resolution, and dynamic behavior.
Both analytical and computation This research effort addresses the need to develop and models are being developed and verified with experi- understand coupled hybrid magnetomechanical com- A.
Piezoelectric bimorph configuration left that allows actuation via a non-contact electron gun source that can target multiple locations of the distributed active surface right. Courtesy of J. Main, University of Kentucky. The composite represents a mag- basic science questions is to what extent does magnetic netostrictive active material that elastically deforms interaction between dissimilar particles contribute to alt- when subjected to an external magnetic field.
It contains ering the internal magnetic circuit.
The magnetic field several advantages when compared to the monolithic applied during cure aligns the particulates into continu- magnetostrictive materials, including increased fracture ous chains and forms a continuous magnetic circuit toughness, reduced hysteresis, larger bandwidth within the material.
One of the primary Fig. Schematic illustrating formation of magnetostrictive composites upper. Performance of magnetostrictive composites of varied volume fractions lower left and using different magnetostrictive particle sizes to tailor strain output potential under varied stress lower right.
Carman, University of California at Los Angeles. Synthesis of smart material actuator systems for 3. Remote sensing of damage in large civil low- and high-frequency macro motion: an analytical structures using embedded sensors for hazard and experimental investigation, G. Naganathan mitigation, D. Pines University of Maryland University of Toledo The project involves integrating research and edu- This project is to demonstrate that motions of a few cation to advance the technology of smart materials and centimeters can be performed by smart material actuator structures and techniques to remotely monitor damage systems.
A program that combines theoretical investi- in large civil structures. The research focuses on the gations and experimental demonstrations is being con- development of a smart civil structure with embedded ducted. Potential configurations made of piezoceramic piezoelectric sensors for inferring structural damage. The and electrostrictive materials are being evaluated for pro- research will emphasize the integration of embedded viding larger motions at reasonable force levels for sensors, actuators and processors into load-carrying applications.
Laboratory demonstration of remote health monitoring and damage detection. Courtesy of D. Pines, University of Maryland. Magnetostrictive transducer strain per magnetization bode plot and strain versus magnetization minor loops. Hysteresis minor loop data collected at from left to right : 10, , , , , , and Hz.
Courtesy of A. Nancy Johnson for pursuing and managing the creation of the special issue, and I am looking forward to seeing smart product design a growing area of publication in JMD. Panos Y. As was discussed in the March editorial on Design Innovation, JMD embraces a wide variety of design-oriented research papers, including those on smart materials, structures and systems. This special issue focuses on innovative technologies and new methods to design and analyze these devices.
Smart materials and structures can be thought of as those that adapt to their environment in some way, and they often provide previously unattainable functionality and performance.
Smart materials alter their mechanical properties or provide some mechanical work in response to an external, e.
A smart structure may incorporate smart material actuators or some other means of adapting to its surroundings. An example of a smart structure is a morphing aircraft wing that adjusts its shape to adapt to varying flight conditions. The smart morphing wing may be fully active in that sensors, actuators, and a controller are integrated into the system to adjust the shape of the wing e.
Or the morphing wing may be passive where the structural properties of the wing are tailored such that the wing shape changes in response to aerodynamic surface pressure without the need for external sensors and actuators.
Another example of a smart system is the use of shape memory alloys to automatically control air flow in building HVAC systems which do not need any power or wiring.