Smart materials systems

FIGURE 14.2 (a) Components of a microsystem. (From Hsu, T.-R. MEMS Microsystems Design and Manufacture, 1st ed., McGraw-Hill, Boston, 2002.). (b) A smart material system (From Wallace, G.G., Spinks, G.M., Kane-Maguire, L.A.P., and Teasdale, RR., Conductive Electroactive Polymers Intelligent Materials Systems, 2nd ed., CRC Press, Boca Raton, 2002.)... 

Kuhnen, K. Janocha, H. Inverse feedforward controller for complex hysteretic nonlinearities in smart material systems. Control and Intel . Sys. 29, 3 (2001), pp. 74-83... 

The design of smart materials and adaptive stmctures has required the development of constitutive equations that describe the temperature, stress, strain, and percentage of martensite volume transformation of a shape-memory alloy. These equations can be integrated with similar constitutive equations for composite materials to make possible the quantitative design of stmctures having embedded sensors and actuators for vibration control. The constitutive equations for one-dimensional systems as well as a three-dimensional representation have been developed (7). 

Prahlad, H., Kombluh, R., Pelrine, R., Stanford, S., Eckerle, J., and Oh, S. Polymer power Dielectric elastomers and their applications in distributed actuation and power generation. Proceedings of ISSS International Conference on Smart Materials, Structures and Systems, Bangalore, India, July 28-30, 2005, SA-13, pp. 100-107. 

Cortie, M., Xu, X., Zareie, H., Chowdhury, H. and Smith, G.(12th-15th Dec 2005) Plasmonic heating of gold nanoparticles and its exploitation, presented at Smart Materials, Nano-, and Micro-Smart Systems 11, Sydney, Australia, SPIE, 5649, pp. 565-573. 

Piezoelectric ceramics, which depend on lead compounds, are used to produce transducers and sensors which make possible ultrasound technologies used in wide-ranging medical and commercial applications, guidance and sensing systems used in defense and commerce, and in addition, new "smart materials" research projects. 

We have had smart materials as materials for a long time though the term is relatively new. Some of the first smart materials were piezoelectric materials, such as poly(vinylene fluoride), which emit an electric current when pressure is applied and change volume when a current is passed through it. Most smart materials are polymeric or have a critical portion of the smart system that is polymeric. 

Smart materials are extremely efficient, performing a variety of jobs that would otherwise require researchers and engineers to spend a lot of time and money to develop and design a number of different substances. Materials capable of multitasking are one of the most interesting and promising frontiers of chemistry and materials science. This chapter describes research on a variety of materials and systems that exhibit some degree of responsiveness to their environment. 

Using smart materials in objects such as eyeglasses means that the function can change depending on environmental conditions or the needs of the user. Smart materials can also be critical components of systems— assemblies of interacting parts—that adapt to varying conditions. Such systems are known as adaptive or intelligent systems. 

Light is electromagnetic radiation, and electricity and magnetism, along with optics, are extremely important in science, engineering, and industry. Smart materials and adaptive systems that respond to some aspect of electricity and magnetism are in high demand. A circuit based on electrical resistance was mentioned earlier in the chapter. 

How far can smart materials go Futuristic depictions such as in the 1991 film Terminator 2 have androids made of shape-changing metal that can quickly flow and set into any desired form. A more realistic vision for the future of smart materials and systems can be viewed by observing nature. Organisms move, adapt, and evolve, and they are made of materials that are complex but have been studied by biologists for decades. 

The human body, for instance, has sensors (eyes, ears, touch receptors in the skin, and so forth), a controller (the brain), and actuators (muscles) to react and respond to commands. These are the same basic concepts as the adaptive systems discussed in this chapter. Robots today, such as the welding machines used in industry or the toy dogs sold as pets, are extremely Umited in mobility and adaptability compared to humans. Yet smart materials, along with a design based on the sensory, nervous, and muscular systems of the body, could one day create an agile and adaptable robot. 

Adaptation and evolution have created an astonishing variety of life on this planet. Smart materials and adaptive systems may do the same for instruments, machines, and other technological tools and techniques. The expansion of this scientific frontier has the potential to revolutionize much of the technology that people use for medicine, transportation, and industry. 

General Motors. Intelligent Chassis Control Systems Taking Safety Along for the Ride. 2003. Available online. URL http //media.gm.com/ division/2003 prodinfo/03 corporate/chassis.html. Accessed May 28, 2009. General Motors describes suspension systems that incorporate smart materials. 

A. B. Frazier, M. R. Khan, and M. G. Allen, Symposium Proceedings of the Materials Research Society (Smart Materials Fabrication andMaterialsfor Micro-Electro-Mechanical Systems), San Francisco, Calif., Apr. 28—30,1992, 276, 295—301 (1992). 

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