FINITE-ELEMENTS SIMULATION OF MECHANICAL-BEHAVIOR OF SHAPE-MEMORY ALLOYS COUPLED WITH A NONSTATIONARY THERMAL FIELD

The main deformation mechanisms of shape memory alloys (SMA) are relat ed to martensitic transformation and/or martensitic reorientation. The se phenomena lead to heat production resulting from the transformation and/or from internal dissipation processes. As the SMA behaviour is s trongly temperature dependent, its modelling has to take into account thermomechanical coupling. A 3-dimensional finite element code has bee n designed for that purpose. The quasi-static mechanical behaviour is described through the temperature dependent elastohysteresis model. La rge displacements and large deformations are considered. The numerical problem is strongly non-linear and an implicit resolution scheme has been adopted. Two coupled thermomechanical calculations are presented. The first one deals with the one-way memory effect of a cantilever be am. The second one simulates the non-stationary thermal and mechanical fields of this beam during a near-adiabatic pseudoelastic bending.