Finite Strain Shape Memory Alloys Modeling - Scuola di Dottorato in ...

3D-1D simplified, are performed considering the same beam element of the previoussection. It is first subjected to an increasing value of the axial force at a constanttemperature equal toMf, until a maximum load value P is reached; then, atemperature cycle is prescribed, i.e. the following loading and temperature history isassumed:t[s] 0 1 2 3 4 5 6P[N] 0 250 0 -250 0 0 0T[K] 223 223 223 223 223 400 223In Fig. 8.9 the applied load axial is plotted versus the displacement of a pointbelonging to the free edge, computed using the two different constitutive models. Itis interesting to observe: (1) the presence of a residual strain at the end of theloading-unloading pattern being at temperature equal toMf; (2) the ability tocompletely recover the initial state (zero stress, zero strain) applying a temperaturecycle characterized by a heating process reaching a temperature aboveAfand then acooling process going back to the initial value of the temperature, i.e. to reproducethe shape-memory effect in a uniaxial state of stress.It can be noted that, in a uniaxial state of stress, the use of the simplified SMA modelin a beam finite element does not induce differences in the solution with respect tothe ones recovered adopting the full 3D SMA model.146