Finite element simulation of a multicrystal in shape memory alloy

Abstract
The current increasing tendency is to design small components. Compared to the sample size, the grain size can not be neglected any more. In this case, homogeneous constitutive laws based on scale transition method are not adapted. FEM (Finite Element Method) seems well adapted to take into account the exact shape of each grain, in order to represent correctly the heterogeneous behavior.

In this way, a single crystal constitutive law is developed. It describes the superelastic effect in SMA. This model is introduced in the Abaqus F.E. code via the UMAT routine in order to simulate a multicrystal SMA behavior (23 grains). This multicrystal is meshed using tridimensional isoparametric elements taking into account the shape of each grain. Boundary conditions corresponding to a pure tension loading are introduced. The different results obtained are the evolution of the martensite volume fraction inside grains, the behavior of each grain, the effect of heterogeneity on the deformed shape is observed also.