Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 597
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Full Record for Micrograph 597

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Micrograph no
597
Brief description
Frozen stress photoelastic fringe pattern during fibre pushout
Keywords
Araldite, birefringence Link to MATTER Glossary entry for birefringence, composite material Link to MATTER Glossary entry for composite material, fibre Link to MATTER Glossary entry for fibre, load distribution, photoelasticity Link to MATTER Glossary entry for photoelasticity, polymer Link to MATTER Glossary entry for polymer, polymer composite, pushout, reinforcement Link to MATTER Glossary entry for reinforcement, residual stress Link to MATTER Glossary entry for residual stress, shear Link to MATTER Glossary entry for shear
Categories
Composite, Polymer, Polymer composite
System
Araldite (TM)
Composition
Araldite CT200/HT907 'matrix' with cylindrical CT200/HT901 'fibre'
Standard codes
Reaction
Araldite is a thermoset polymer, formed by the reaction of an epoxy resin with a hardener. In this case, the epoxy resin is CT200 and the hardeners are HT901 and HT907
Processing
A 'reinforcement particle' was cast, cured and machined into a cylinder, and the 'matrix' cast and cured around it. A load was applied at 135deg C and stresses 'frozen in' by slow cooling through Tg
Applications
Mechanical characteristics of the fibre-matrix interface are of central importance for composite materials. The distribution of shear stress along the interface is critical to the load distribution and can be evaluated by this method.
Sample preparation
A quarter wave plate has been inserted to remove isoclinic fringes
Technique
Cross-polarised light microscopy
Length bar
6 mm
Further information
The experiment indicates a more uniform of shear stress than that predicted by the shear lag model, suggesting that interfacial shear de-bonding strength values obtained from de-bonding loads on the basis of that model may be overestimates. (See 'The use of single fibre pushout testing to explore interfacial mechanisms in SiC monofilament-reinforced Ti-I. A photoelastic study of the test', Watson and Clyne, Acta metall. mater. Vol 40, No 1, pp 131-139, 1992 for more details.)
Contributor
Prof T W Clyne
Organisation
Department of Materials Science and Metallurgy, University of Cambridge
Date
03/10/02
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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