Experimental study on the tensile behavior of unidirectional and plain weave CFRP laminates under different strain rates

• Published in: Composites. Part B, Engineering Vol. 164; pp. 524 - 536
• Main Authors: Zhang, Xuejie, Shi, Yanchao, Li, Zhong-Xian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2019
• Subjects: Dynamic increase factor; Dynamic tensile tests; Plain weave carbon/epoxy composite; Strain rate effect; Unidirectional carbon/epoxy composite; Dynamic increase factor; Plain weave carbon/epoxy composite; Unidirectional carbon/epoxy composite; Strain rate effect; Dynamic tensile tests
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2019.01.067

In the present work, static and dynamic tensile tests of unidirectional and plain weave CFRP laminates used for retrofitting building structures were carried out using a universal testing machine and a high-speed servo-hydraulic testing machine (INSTRON VHS 160/100-20), respectively. The strain rate that the CFRP laminate experienced in the tests varies from 4E-5s−1 to 160s−1. Test results show that the tensile behavior of both unidirectional CFRP and plain weave CFRP are strain rate dependent, while the latter is more obvious than the former. Failure processes of the CFRP laminates were also observed with the aid of a high-speed camera. It is found that the failure mode of the CFRP laminate at high strain rate is quite different from that at quasi-static loading and low strain rate, which is believed to contribute to the strain rate sensitivity of both the unidirectional and plain weave CFRP laminate. Empirical formulas of dynamic increase factor (DIF) of tensile strength, Young's modulus and failure strain of the CFRP laminates were derived as a function of strain rate within the strain rate range tested. Available testing data were also collected from other papers and analyzed together with the testing data from the present study.