Shape Memory Alloys Cyclic Behavior: Experimental Study and Modeling

Abstract

Shape memory alloys (SMA) are good candidates for being integrated in composite laminates where they can be used as passive dampers, strain sensors, stiffness or shape drivers. In order to improve the SMA modeling and develop the use of these alloys in structural vibration control, better understandings of cyclic behavior and thermal dissipation are needed. The present study investigates experimentally the cyclic behavior of SMA and more particularly, the influence of strain rates on three different materials. The thermal dissipation aspect is also studied using an infrared camera. A phenomenological model based on the RL model (, , 1994, “ RL Models of Pseudoelasticity and Their Specification for Shape Memory Solids.” Eur. J. A/Solids, 13, pp. 21–50) is then presented with the intention of modeling the behavior’s alterations due to the cycling. By introducing the thermodynamic first principle, a study of the heat equation is developed in order to predict the temperature evolution during a cyclic tensile test. Furthermore, in order to model the damping effect created by the hysteresis phenomenon and the stiffness variation due to the phase transformation, an equivalent nonlinear complex Young’s modulus is introduced. This notion usually used for viscoelastic materials is adapted here to SMA. Moreover, the impact of cycling on the equivalent modulus is presented. As a conclusion, a numerical results panel obtained with the phenomenological cyclic SMA model, the heat equation, and the equivalent complex Young modulus is presented.