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Date of Publication:2014-01-01

Journal:宇航学报

Affiliation of Author(s):运载工程与力学学部

Issue:7

Page Number:850-856

ISSN No.:1000-1328

Abstract:Tensile-compression fatigue properties of T700 carbon fibers/epoxy composite materials after cryogenic treatment are studied in this paper. The unidirectional T700 carbon fibers/epoxy composite materials are manufactured by using a vacuum bag-autoclave moulding-process. In liquid nitrogen, the samples are treated through cryogenic immersing and cryogenic/room temperature cycling respectively. Microcracks of samples after cryogenic treatment are investigated by using a optics microscope. Both static strength and residual strength after tensile-compression fatigue 1000 times, 10000 times and 130000 times of samples are investigated after the cryogenic treatment. Cryogenic damage mechanism of T700 carbon fibers/epoxy composite material is analyzed. The influence of cryogenic treatment and tensile-compression fatigue on residual strength of the composite material is discussed. As the results shown, microcracks will be presented after the cryogenic treatment or tensile-compression fatigue. And the microcracks will cause releasing residual stress and reducing residual strength. The times of tensile-compression fatigue is different when the residual strengths come to the maximum for the samples after different cryogenic treatment. The residual strengths of samples will first raise and then lower with different cryogenic treatments and tensile-compression fatigues.

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