Date of Award

Winter 2014

Project Type

Thesis

Program or Major

Mechanical Engineering

Degree Name

Master of Science

First Advisor

Todd S Gross

Second Advisor

Igor Tsukrov

Third Advisor

John Tsavalas

Abstract

Microcracking and failure in the resin pockets of 3D woven composites is caused by coefficient of thermal expansion mismatch between composite components during cooling from the curing temperature. The failure of the matrix is known to be dependent on triaxial stress state. This study presents first measurements of the effect of pure hydrostatic stress on the failure of epoxy resin as a function of temperature. We found that failure triaxial stress for epoxy resin is not strongly temperature dependent. Strategies to reduce or eliminate microcrackings by means of modifications of the curing schedule are also presented. We show that it is possible to reduce residual stresses and microcracking by curing the epoxy in a carefully crafted heating profile.

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