The Development of Active and Sensitive Structural Material Systems
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The Development of Active and Sensitive Structural Material Systems Hiroshi Asanuma Department of Electronics and Mechanical Engineering, Chiba University, 1-33 Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan ABSTRACT This paper describes new concepts the author has proposed and demonstrated to realize metal and polymer based sensitive and/or active structural material systems suitable for smart structures. Most of the developments have been done by simple and innovative methods without using sophisticated and expensive sensors and actuators. The following topics are mainly examined: (1) forming optical interference and loss type strain sensors in epoxy matrix simply by embedding and breaking notched optical fiber in it; (2) forming a multifunctional sensor in aluminum matrix for temperature and strain monitorings by embedding an oxidized nickel fiber; (3) fabricating multifunctional composites by using conventional structural materials an active laminate of CFRP/aluminum of which unidirectional actuation is realized by electrical resistance heating of carbon fiber in the CFRP layer and its curvature change can be monitored using optical fiber multiply fractured in the CFRP layer; (4) fabricating active fiber-reinforced metals such as SiC/Al and SiC/Ni systems by laminating a reinforced layer with a unreinforced layer to cause thermal deformation. In the case of SiC/Al composite, actuation was performed only in the fiber direction and is useful for making a light-weight active panel. In the case of SiC/Ni composite, actuation took place up to above 1200K and is useful for making a high temperature actuator.
INTRODUCTION Smart material systems are attracting worldwide interest because of their potential uses: damage detection, health monitoring, noise reduction, vibration suppression, actuation, self repair, and fabrication process monitoring [1]. Most of these new material systems have been developed by embedding sensor and/or actuator materials in host structural materials such as polymer matrix composites. Active and sensitive material systems will be able to replace or simplify complicated mechanical systems as shown in Figure 1. They will remove, for example, heavy and complicated actuation systems, hinges and tribological problems. Light-weight, high-strength and active/sensitive structural materials could be applied to many active parts for high speed vehicles such as hatches, doors, flaps and air brakes, or could be applied to innovative wings and bodies. Figure 2 shows a major direction of the author's researches, where an active composite material with embedded functional fiber is proposed. The reinforcement fiber works as "bone" and the matrix material works as "muscle" for actuation which is controlled by stimulation and energy transmitted through the functional fibers regarded as "nerve" and "blood vessel." This material system could have a variety of functions [2]. In this paper, new concepts the author has proposed and demonstrated to realize metal and polymer based sensitive and/or acti
