| Popis: |
This paper presents a novel approach concerning the development of an orthotropic damage model, based on the original plane Tsai-Wu failure criteria. In its original formulation, the Tsai-Wu is a mode independent criterion only capable of acknowledging the existence of damage in a certain point of the material. It is not capable of identifying if the damage is located in the fiber, matrix or intralaminar zone. This work plans to fill this gap in knowledge by providing a simple method, based on equivalent stress and strains, that identifies the failure modes when the Tsai-Wu failure criteria is near the on-set of damage. Using this novel method, it is possible to implement classical damage evolutions constitutive laws based on the MTL formulation. At the moment the proposed damage formulation is based on plane stress space and Mode I fracture, but it is expected in the future to evolve in to a full 3D damage model. The damage model is implemented in the commercial finite element software ABAQUS using user-subroutine UMAT, and all numerical models are compared with the experimental results. |
