Degree Type

Dissertation

Date of Award

2019

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

Major

Mechanical Engineering

First Advisor

Adarsh Krishnamurthy

Abstract

Laminated fiber-reinforced polymer (FRP) composites show considerable promise in structural applications due to their good combination of low weight and high strength. However, the manufacturing costs of laminated composites is significantly higher than their metallic counterparts. As a consequence, estimating the residual life of composites becomes critical, and can enable reusability in applications that demand lower mechanical strength requirements. One of the major factors affecting the residual life of the laminated composites is the defects introduced during manufacturing or in service. A common way of determining defects in the composite laminates is using non-destructive evaluation (NDE) techniques. In this study, a framework for modeling and structural analysis of composite laminates is presented. The framework follows the laminate manufacturing process and incorporates structural elements, such as stiffeners, as well as defects, such as delaminations, determined using NDE techniques. Each layer composing the laminate is modeled separately and combined to generate the final laminate. The layer combination process is called bonding and involves computation of boundary conditions for the constitutional model being selected for the analysis. Then, the final laminate model and the computed boundary conditions are used during the structural analysis. The initial framework used commercial off-the-shelf (COTS) software, i.e. 3D ACIS Modeler for 3-dimensional modeling and SIMULIA Abaqus for structural analysis via finite element modeling. The framework was then extended to use the NURBS library, NURBS-Python, and the isogeometric analysis library, gIGA, which were developed as a part of this study and released as free and open-source software on GitHub. Using NURBS for modeling and isogeometric analysis for structural analysis provide several advantages, such as directly operating on the exact geometry, and therefore; achieving better estimations on interlaminar and intralaminar stresses and strains, which has significant importance in determining the residual life of the composite laminates.

Copyright Owner

Onur Rauf Bingol

Language

en

File Format

application/pdf

File Size

105 pages

Share

COinS