Yu-Jui Liang

Graduation Semester and Year

2019

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Endel V. Iarve

Abstract

The Regularized eXtended Finite Element Method (Rx-FEM) methodology is a discrete damage modeling (DDM) technique, which represents an approach to the progressive damage analysis (PDA) in laminated composites when multiple damage events such as matrix cracks and delamination are introduced into the model via the displacement discontinuities. In the Rx-FEM, the Heaviside step function that is typically used to introduce a displacement discontinuity across a crack surface in the eXtended Finite Element Method (x-FEM) is replaced by a continuous function approximated by using the finite element (FE) shape functions. This regularization offers unique possibility for the implementation of the Rx-FEM methodology in commercial finite element software which has many advantages including the powerful solver, built-in capabilities, post-processing, and visualization. The proposed implementation of the Rx-FEM methodology in Abaqus consists of the mesh-independent cracking (MIC) technique to modeling the transverse matrix cracks in each ply of the composite laminate, and modeling the delamination between plies by using the mixed-mode cohesive formulation which is also used to describe the MIC matrix crack propagation characteristics, and the interaction between matrix crack and delamination. The validity of the proposed implementation is tested by several verification models of MIC modeling in composite laminates, and delamination between plies. The proposed implementation not only demonstrates accurate predictions, but also allows to take advantages of various built-in capabilities from the host software Abaqus such as geometrically nonlinear solution, contact interactions, post-processing, and visualization. More importantly, it opens up a new venue for the Rx-FEM implementation across different element platforms including multiphysics applications.

Keywords

Regularized eXtended Finite Element Method (Rx-FEM), Laminated composites, Fracture, ABAQUS

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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