Shape memory alloys cyclic behavior:: Experimental study and modeling

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 an develop the use of these alloys in structural vibration control, better understandings of cyclic behaviour 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 (Raniecki, B. Lexcellent, C. 1994 "R-L Models of Pseudoelasticity and Their Specification for Shape Memory solids, "Eur J A/Solids. 13. pp. 21-50) is then presented wit the intention of the 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 rite 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 tire phase transformation, air equi. valent nonlinear complex Young's modulus is introduced. This notion usually used for viscoelastic materials is adapted here to SMA. Moreover tire impact of cycling on the equivalent modulus is presented. As a conclusion, a numerical results panel obtained with the phenomenalogical cyclic SMA model, rite treat equation. and rite equivalent complex Young modulus is presented.