Development and evaluation of intelligent composite material--artifitial mascle--with the use of LRM model

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In the present effort of the proposed project research, development of an intelligent material that furnishes the capability of an actuator with a high degree of freedom is performed. The material also aims at its biomedical compatibility with the surrounding tissues as it is embedded in the body. Micro-actuator device elements that are dispersed in the matrix material is considered to generate power to the intelligent material. In the present effort, the following results and knowledge were obtained.(1)The biomedical compatibility will become a critical factor if the intelligent material is embedded in the human tissue, so that the selection of the used material will need a separate address. In order to secure high degrees of freedom of deformation mode, a device of actuators dispersed in the soft matrix material comparable to human muscle is designed. Thus a muscle movement of high degrees of freedom is made possible.(2)For micro-actuators, piezo-elastic material is selected. The pie … More zo material, however, generates only small strains that a sufficient stroke of the artificial muscle can not be secured. For that reason, a uni-morph or a bi-morph spring was devised, in which a thin micro-plates made of piezo-elastic materials are glued with each other to form a spring wire. A number of such micro-springs are located in a soft matrix material to form the artificial muscle. Calculated results showed that 30 to 40 percent of spring extension will be possible when powered for the present artificial muscle with the use of the uni-morph spring.(3)For the FEM analysis of the material, a constitutive model (SCC-LRM) is developed based on the self-consistent type equivalent inclusion theory. Performed analysis showed a successful prediction of arbitrary movement of the artificial muscle in high degrees of freedom. An application of the analysis system to a cantilever muscle problem showed the demonstration of very large swing motions when electrical energy is supplied to the piezo springs.(4)We found a possibility of practical application of the present development to an artificial heart of the type where the wall of the heart itself moves and pumps blood. Since the behavior of the heart system is close to that of the natural human heart, the blood stream will rather be smooth unlike the case seen in the existing artificial heart pump, and therefore minimize the chance of generating harmful blood clots. This idea was proposed and the research has currently been under way since the year 2003 funded by the Grant-in-aid for Scientific Research. Less