A new interface element with hydro-mechanical coupling

by S. Granet and B. Carrier, EDF R&D / AMA

A new interface element with hydro-mechanical coupling has been introduced in version 10.2 of Code_Aster. This element is used to discretize a joint between two solids described by elements HM 2D and axisymmetric. Thanks to this development by Benoit Carrier (intern ENPC), we can study the influence of a crack on the permeability of a rock saturated by a liquid or a gas.

The coupling between mechanical and hydraulic is provided by two new constitutive laws. Bandi’s law connects the crack opening to the fluid pressure applied to her lips. The cubic law is used to write the hydraulic transmissivity of the crack in terms of its opening. Moreover, the fluid exchanges are allowed between the crack and the surrounding mass.

The joint element is also compatible with the cohesive laws regularized (and CZM_LIN_REG CZM_EXP_REG). This allows to describe the flow in a crack that spreads but also to simulate crack propagation in fluid pressure, with or without exchange with the surrounding solid.