Doctoral Dissertations

Author

Huanqiu Tang

Abstract

"A micromechanics analytical model is developed for predicting the fracture behavior of a fiber reinforced composite laminate with sub laminate damage. The model is also modified to facilitate the study of an interface crack in a bimaterial system and the thermal and moisture effects. The two-dimensional constitutive equations for an orthotropic linear elastic material are used to represent the stress-displacement relations. The governing equations arc solved satisfying the boundary conditions appropriate to the damage mode by making use of an eigenvalue technique.

For a laminate containing transverse crack and longitudinal splitting the displacements and stresses in the fibers and the matrix arc obtained, and the growth of damage is investigated by using a point stress failure criterion. The investigation includes fiber stress distribution in zero degree plies, transverse crack initiation as a function of laminate thickness and thickness of each ply, and effect of fiber breaks in the zero degree ply on damage growth. A number of practical laminate configurations are studied analytically for assessing their fracture behavior at the sublaminate level. The predicted damage growth patterns and the corresponding loads are compared with available experimental results.

A criterion based on energy release rate and phase angle is developed to determine whether an interface crack in a bimaterial will deflect into the interface or penetrate through it once the crack reaches the interface. The modes of propagation, crack deflection and penetration, are presented for different material properties of the constituents of a bimaterial system, the thickness and elastic constants of a third material in front of the crack tip, periodically arranged bimaterial strips and the effect of thermal and moisture residual stresses"--Abstract, p. iii

Advisor(s)

Dharani, Lokeswarappa R.

Committee Member(s)

Cronin, D. L.
Chandrashekhara, K.
Moore, Robert E., 1930-2003
Hicks, Troy L.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Engineering Mechanics

Publisher

University of Missouri--Rolla

Publication Date

Spring 1990

Pagination

xi, 120 pages

Note about bibliography

Includes bibliographical references (pages 111-119)

Rights

© 1990 Huanqiu Tang, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 6070

Print OCLC #

23234464

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