A variational model for plastic reorientation in fibrous material: numerical experiments on phase segregation

We propose a continuum model of fibrous material that may undergo an internal reorganization, which turns out in a plastic change of the orientation of the fibers when the remodeling torque achieves a threshold. We have recently found that the reorientation may induce a complex scenario in the response of such materials. In a traction test, we show that the most general transversely isotropic material may evolve in three different ways; in particular, the fibers asymptotically tend (regularly or with jumps): (A) to a given angle; (B) to align perpendicularly to the load direction; (C) to align with the load direction if their initial orientation is less than a given value otherwise perpendicularly. We focus on the latter material response (C) which has all the ingredients to manifest a phase transition phenomenon. Finally, we provide a numerical investigation to demonstrate phase segregation.