ORCID Identifier(s)

0000-0002-0819-6998

Graduation Semester and Year

2017

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Seiichi Nomura

Abstract

Composite materials fail for various reasons and extensive research has been conducted both experimentally and theoretically. However, theoretical prediction of composite failure by yielding seems scarce. Adding reinforcing elements to matrix significantly affects the structural behavior of composite materials. The inserted particles on one hand obstruct the progress of cracks and on the other hand cause stress concentration on the interface of the particle-matrix and eventually influence the ultimate strength of the material. In this research, we study the interface stresses and strength in particulate reinforced composites under uniform mechanical and thermal loading. We theoretically obtain failure envelopes for particulate reinforced composites. This is achieved by estimating the stress field in the matrix phase around a spheroidal particle in an unbounded matrix phase along with the self-consistent approximation that determines the effective elastic modulus of the composite. The failure envelopes are calculated on the basis of the maximum von Mises stress as a function of the applied far-field stresses or heat flow. We also discuss the effect of the particle volume fractions and the particle to matrix stiffness ratios on the interface stresses and ultimate yielding strength. Parametric analysis enables us to predict these envelopes for various loading conditions, volume fractions and particle to matrix stiffness ratios.

Keywords

Failure envelopes, Particulate reinforced, Composites, Micromechanics, Yielding onset

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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