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http://bura.brunel.ac.uk/handle/2438/2345
Title: | Creep in fibre-reinforced polymer mat composites |
Authors: | Rees, DWA Garner, AF Dix, S |
Issue Date: | 2007 |
Publisher: | Engineering Integrity Society |
Citation: | Engineering Integrity. 23, 6-13 |
Abstract: | Tensile creeps have been conducted upon a woven, glass-fibre laminated epoxy composite and a 0/90° cross ply, carbon fibre reinforced epoxy composite. For the laminate loading was aligned with a fibre direction. For the ply the loading was inclined to the fibres (off-axis). Testing to stress levels up to 200 MPa and temperatures in the range 20°- 200°C has revealed a form of creep in each material. The creep observed is essentially primary in nature but with extended time •1000 h, it may exhaust or resemble a pseudo-secondary regime with a low rate. Where the load carrying capacity is lost, through fibre breakage or tab slip, the creep rate accelerates suddenly to infinity in a few hours. Smooth creep curves apply to successful tests but many irregular curves resulted from grip failure. A phenomenological approach was used to model smooth curves using a summation of instantaneous, primary and secondary strain terms. For the mat reinforcement a consistent trend was not found between the secondary creep rate and a stress that was raised incrementally upon the same testpiece. However the cumulative instantaneous strain provided the correct elastic modulus. Creep in the solid laminate was believed to be due to a fibre straightening that yielded a limiting strain in a time beyond which the process exhausts. Creep in cfrc was only evident when the fibres were inclined to the stress axis, indicating a viscous flow in the matrix. Moreover, it is believed that a viscous shear sliding between laminates or plies is more likely to contribute to an off-axis deformation mode which is not strain limited. |
URI: | http://bura.brunel.ac.uk/handle/2438/2345 |
Appears in Collections: | Materials Engineering Brunel Design School Research Papers |
Files in This Item:
File | Description | Size | Format | |
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Creep in fibre-reinforced polymer mat composites.pdf | 673.22 kB | Adobe PDF | View/Open |
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