Microscopic delamination processes and the resulting crack tip strain fields of graphite/epoxy composites /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The microscopic failure mechanisms for five graphite/epoxy composites with different degrees of resin toughness were examined. Correlations between these failure mechanisms and the resulting delamination toughness were made for mode I, mode II and mixed mode loadings. A combination of scanning electron microscope (SEM) real time fracture observations and post-failure fractography was used to identify the microscopic fracture mechanisms. The mode I, mode II and mixed mode energy release rates were determined using unidirectional double cantilever beam specimens. The mode I delamination energy release rate, G[Ic], was calculated using linear beam theory, an area method, and a compliance calibration analysis. The results from these three different methods of analysis were compared and discussed. Two techniques for measuring the microscopic crack tip strain field s were developed and tested. These techniques used stereoimaging and direct measurement of the crack tip displacements from SEM electron beam induced reference marks. Both methods were shown to be easy and viable means of measuring the microscopic crack tip displacements and strains. Also, careful observations of the neat resin and composite fractured surfaces were made to evaluate the use of fracture morphology in failure analysis of composite materials. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Interdisciplinary Engineering." |
| Physical Description: | xiv, 224 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 219-223). |