The present paper describes development of active laminates and composites proposed by Asanuma. The active laminates were successfully made by hot-pressing of an aluminum plate as a high CTE (Coefficient of Thermal Expansion) material, a unidirectional CFRP (Carbon Fiber Reinforced Plastics) prepreg as a low CTE material and an electric resistance heater, and a KFRP (Kevlar Fiber Reinforced Plastics) prepreg as a low CTE material and an insulator between them. Curvature of the active laminate linearly changes only in the fiber direction as a function of temperature, and it was made into complicated forms and their actuation performances were successfully demonstrated. As a high temperature type active laminate, three types of SiC/Al composites, that is, a laminate of continuous-fiber layer and unreinforced one, that of discontinuous-fiber layer and unreinforced one, and that of continuous-fiber layer and discontinuous-fiber one were fabricated, and it became clear that all of the composites curve unidirectionally in the fiber direction, and the curvatures reproducibly change during thermal cycles between room temperature and 813 K. Tensile strength of the combination type is higher than that of the continuous-fiber type, and its curvature exists between the continuous-fiber type and the discontinuous-fiber type.
Estimation of Plastic Zone Size in Cracked Continuous Fiber-Reinforced Plastics.