Paper number 555


Rebecca Sinclair and Robert J. Young

Manchester Materials Science Centre,
UMIST/University of Manchester,
Grosvenor Street, Manchester, M1 7HS UK.

Summary The indentation or pushout test is a widespread method of evaluating composite interfaces. Pushout tests have been performed on three types of ?-alumina fibre embedded in epoxy resin: Nextel 610, PRD-166; and Saphikon. It has been found that all three fibres exhibit a well-defined fluorescence spectrum consisting of two approximately Lorentzian peaks; and that when compressive strain is applied, the peaks in the spectrum shift towards lower wavenumbers. The shift, measured in cm-1, is linear with respect to applied strain. The fluorescence spectra of the fibres were found to shift by approximately 8-10 cm-1 for each 1% of applied strain. This information was used to calculate the point-to-point axial strain variation in the embedded fibres. The fluorescence probe method of evaluating pushout tests is capable of producing sensitive and accurate information that is useful for understanding the stress distributions in the test.
Keywords micromechanics, pushout, fluorescence spectroscopy, alumina fibres.

Theme : Interface and Interphase ; Mechanical Properties

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