A constitutive model of shape memory alloy with temperature memory effect

Abstract

Temperature memory effect occurring in some shape memory alloys has potential values in various fields such as smart materials and structures, and so on. It is of theoretical and practical interests to develop a new constitutive model of shape memory alloy to overcome the limitation that the previous constitutive models of shape memory alloy failed to express the temperature memory effect of shape memory alloy. This paper focuses on the foregoing issue based on the previous work of the authors. A new shape memory equation is developed to describe the relationship of shape memory factor, stress and temperature in shape memory alloy using the differential relationship of phase transformation free energy and martensitic volume fraction and the concept of shape memory factor defined by the author of this paper. A new mechanical constitutive equation is developed to predict the relationship of strain, stress and temperature in shape memory alloy based on the thermodynamics and continuum medium mechanics. The supposed constitutive model of shape memory alloy, which includes the new shape memory equation and new mechanical constitutive equation, is able to overcome the limitation that previous constitutive models of shape memory alloy failed to express the temperature memory effect of shape memory alloy. This work can provide a theoretical basis for the practical applications of temperature memory effect of shape memory alloy in various fields.