Micromorphic vs. phase field approaches for gradient viscoplasticity and phase transformations

Samuel Forest (1) , Kais Ammar (1) , Benoit Appolaire (2)

1 CDM - Centre des Matériaux
2 LEM - ONERA - CNRS - Laboratoire d'étude des microstructures [Châtillon]

Strain gradient models and generalized continua are increasingly used to introduce characteristic lengths in the mechanical behavior of materials with microstructure. On the other hand, phase-field models have proved to be efficient tools to simulate microstructure evolution due to thermodynamical processes in the presence of mechanical deformation. It is shown that both methods have strong connections from the point of view of thermomechanical field theory. A general formulation of thermomechanics with additional degrees of freedom is presented that encompasses both applications as special cases. It is based on the introduction of additional power of internal forces introducing generalized stresses. The current knowledge in the formulation of physically non-linear constitutive equations is used to develop strongly coupled elastoviscoplastic material models involving phase transformation and moving boundaries.

Domaines: Matériaux

Samuel Forest, Kais Ammar, Benoit Appolaire. Micromorphic vs. phase field approaches for gradient viscoplasticity and phase transformations. B. Markert. Advances in extended and multifield theories for continua, Springer, pp.69-88, 2011, Lecture Notes in Applied and Computational Mechanics, 978-3-642-22737-0. ⟨10.1007/978-3-642-22738-7_4⟩. ⟨hal-00683083⟩