Accession Number : ADA314348

Title :   Modeling of Thin Layer Extensional Thermoelectric SMA Actuators.

Corporate Author : TEXAS A AND M UNIV COLLEGE STATION CENTER FOR MECHANICS OF COMPOSITES

Personal Author(s) : Lagoudas, D. C. ; Bhattacharyya, A.

PDF Url : ADA314348

Report Date : 1996

Pagination or Media Count : 43

Abstract : As a first step towards the design of a high frequency, high force, large strain shape memory alloy(SMA) actuator, we model in this work a thermoelectrically cooled thin SMA layer linear actuator. The SMA is subjected to cyclic phase transition between the martensitic and austenitic phases by alternate heating/cooling, achieved with the thermoelectric Peltier effect of a pair of P/N semiconductors. The effect of variable actuating load and constant load applied as boundary conditions on the SMA actuator are considered. The thermomechanical boundary value problem involves strongly coupled thermal and mechanical fields. The evolution equations for the field variables are integrated using the fourth-order Runge Kutta method and the coupling between the fields is accounted for by implementing an interative scheme. The primary parameters of interest in this work are the frequency response and evolution of the variable load. The performance of the actuator is compared with various commercially available actuators based on energy conversion efficiencies and energy output per unit volume of active material. Results of the analysis indicate that thin SMA layers( 6?i thick) under partial phase transformation are capable of delivering frequencies of about 30 Hz at peak stresses of about 145 MPa.

Descriptors :   *THERMOMECHANICS, *ACTUATORS, THERMAL PROPERTIES, COUPLING(INTERACTION), LINEAR SYSTEMS, PEAK VALUES, MECHANICAL PROPERTIES, PARAMETERS, PHASE TRANSFORMATIONS, LOADS(FORCES), EFFICIENCY, COOLING, AUSTENITE, ENERGY CONVERSION, BOUNDARY VALUE PROBLEMS, HEATING, FREQUENCY RESPONSE, MARTENSITE, THERMOELECTRICITY, PELTIER EFFECT.

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE