Date of Award

2017

Document Type

Open Access Dissertation

Department

Mechanical Engineering

First Advisor

Addis Kidane

Abstract

Fiber reinforced composites have been used in various engineering structures and applications especially in naval, automotive, aeronautical and sports industries. These composite materials generally exhibit brittle damage behavior. The anisotropy in the material and different kinds of failure mechanisms make it difficult to accurately characterize the behavior of composite materials. The present work aims to verify and apply the Puck Failure Criteria using the commercially available finite element package ABAQUS by writing a user-material subroutine in FORTRAN. The model is implemented with different post failure degradation schemes.

In the present work, the progressive failure on composite materials in analyzed using the Puck failure criteria to detect damage initiation. The ABAQUS user defined material subroutine UMAT was developed to apply the failure criteria and degradation models. The progressive failure analysis of a single lamina of a composite material is carried out on an open hole specimen under uniaxial tension. A partial discount method and a gradual stiffness degradation method is implemented and the results using these degradation models are compared. The damage initiation and progression obtained from the proposed model is compared with the observed experimental results and the digital image correlation data. This model was then used for the progressive failure analysis of a composite laminate with a central hole loaded in inplane tension with different stacking sequences and compared with the results obtained from literature.

From the results, it can be seen that the Puck failure hypothesis is a robust and versatile criteria which can be used for the progressive failure analysis of continuous fiber unidirectional composite laminates.

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