Mechanical Engineering ETDs

Publication Date

12-20-1974

Abstract

The concept of continuously distributed dislocations is used to investigate the mechanical behavior of fractured composite materials,

As a first approximation to the complicated physical configuration of a composite material, the current investigation concerns a simp1ified physical model by considering an elastic circular cylindrical inclusion imbedded and located in an infinite elastic medium such that an internal line crack starts from the interface and extends in the radial direction of the inclusion. The plastic zone spreads and extends from the crack tip when the entire system is subjected to a uniformly distributed shear load at infinity. This constitutes an anti-pane deformation. A unified description of both the crack and the slip plane is achieved by using the dislocation model.

Exact solutions in closed forms are obtained for systems with heterogeneity parameter K = 1 (rigid inclusion), O (homogeneous), and -1 (cavity), respectively, A numerical scheme has been developed for the case of elastic inclusion.

In particular, effects of the inclusion on such parameters are examined. They are: (a) the distribution of dislocation along the crack and the plastic zone, (b) the relationship between the applied load and the plastic zone, (c) the shear displacement along the crack and the plastic zone, (d) the crack opening displacement at the crack tip, and (e) the fracture load by using critical crack tip opening displacement criterion for fracture.

Both the rigid inclusion case and the cavity case serve as two limiting cases in systems of fractured composite materials. The former reinforces the blunted system, while the latter accelerates its failure. The elastic inclusion exhibits an intermediate effect.

Degree Name

Mechanical Engineering

Level of Degree

Doctoral

Department Name

Mechanical Engineering

First Committee Member (Chair)

Youn-Chang Hsu

Second Committee Member

Howard Linn Schreyer

Third Committee Member

Frederick Dsuin Ju

Fourth Committee Member

Steven Arthur Pruess

Fifth Committee Member

William E. Warren

Document Type

Dissertation

Language

English

Download

Share

COinS