Author

Fu-ken Hsieh

Date of Graduation

1994

Document Type

Dissertation/Thesis

Abstract

One of the most useful attribute of reinforced fibrous composites is its ability to retard crack propagation and thereby improve its overall fracture resistance. Research on the fracture behavior of continuous fiber reinforced metal matrix composites (MMC's) is critical to assessing important engineering properties such as fatigue, impact resistance, creep and durability. The mechanism of interfacial fiber/matrix sliding and debonding in a notched fiber reinforced composite and the corresponding increasing of the overall fracture toughness have been studied in recent years. However, to the best of our knowledge, no direct in-situ experimental measurement of the interfacial sliding and debonding processes has been conducted so far. Although, some qualitative description and analyses have been performed by many researchers. In this research, moire interferometry, which is capable of full field surface deformation measurement, is applied to study the interfacial fracture behavior of unidirectional continuous fiber B/Al MMC at room temperature. The objectives of this research are (1) to analyze the mechanisms of interfacial fiber/matrix sliding and debonding and (2) to investigate the failure criterion for interfacial sliding/debonding based on the measured full-field high resolution moire fringe patterns at notch tip region. A hybrid finite element analysis is also conducted to compare and verify the experimental results. The test results indicated the existence of a critical interfacial shear strain to initiate the T-crack growth. And numerical results compared favorably with experimented results were noted.

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