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Date of Publication:2017-01-01

Journal:复合材料学报

Affiliation of Author(s):运载工程与力学学部

Volume:34

Issue:11

Page Number:2437-2445

ISSN No.:1000-3851

Abstract:Unidirectional carbon fiber reinforced epoxy (CFs/EP)laminate was prepared by vacuum bag molding process.By the combination of high-low temperature test box and universal testing machine,and rational use of low temperature adhesive and low temperature extensometer,cryogenic (liquid oxygen temperature,-183℃)tensile and flexural tests were conducted.During the cooling process,the stress and strain were set to zero timely.Accord-ing to the microscopic and macroscopic characteristics of samples,the cryogenic mechanical properties change mech-anisms of unidirectional CFs/EP laminate were revealed.The results show that,compared with the mechanical properties at room temperature,the cryogenic tensile strength of unidirectional CFs/EP laminates decreases about 9.5%,while the tensile modulus increases by about 6.2%.It is mainly due to that the resin shrinkage between car-bon fibers and resin forms a strong interface at low temperature.The "split"failure mode forms in the cryogenic tensile specimen,which means that not every fiber of unidirectional CFs/EP laminate develop its full strength,and leads to the tensile strength decreasing.While the low temperature limits resin molecular chain movement,which results in the tensile modulus of unidirectional CFs/EP laminates increasing.The cryogenic flexural strength and flexural modulus of CFs/EP laminates are increased to about 54.75% and 11.64%,respectively.It is because the bending failure mode of unidirectional CFs/EP laminates at room temperature and low temperature both are delami-nation shear failure.The cryogenic strong interface of unidirectional CFs/EP laminates improves interlamination shear resistance and makes the cryogenic flexural properties of unidirectional CFs/EP laminates improved.

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