Experimental investigations on polymer matrix composite shaft embedded with shape memory alloy

Abstract

Nowadays many industries, particularly automobile, marine, aerospace, medical and sports science take great efforts to develop materials that present good vibration control to reduce the resonance effects. These applications may demand the materials to perform with multiple characteristics such as high vibration control, good damping capacity, stiffness and specific strength. All these requirements can be fulfilled by the development of smart composites (Composites embedded with Shape Memory Alloy (SMA) wires). These SMA materials can be plastically deformed at relatively less temperatures and when exposed to some higher activation temperatures they will regain their original shapes and hence are being considered for special engineering applications. The strain/shape recovery property of shape memory alloy is due to the increased modulus of elasticity in austenite state. Composites with SMA wires that are pre-strained generate axial recovery tensile forces due to mechanical constraints against shape recovery on activation. Increased modulus of elasticity and generated recovery tensile forces increase the stiffness of SMA composite and thus increasing the natural frequency of the material. Amount of pre-strain in SMA wires and the end conditions of the shaft are some of the prime factors influencing the natural frequency. Moreover, there may be a possibility in smart composites for de-bonding of interface of SMA and composite. Hence the study of mechanical behaviour of composite in activated mode of SMA is also to be considered. newline