Failure behavior of notched CFRP laminates subjected to tensile load

Abstract

An experimental study was conducted to determine the tensile failure mechanism of notched quasi-isotropic carbon-fiber-reinforced plastic (CFRP) laminates. Three sets of specimens were prepared to study the effects of specimen dimensions and stress concentration factor on damage initiation, accumulation and final failure. The damage accumulation processes of the specimens were observed with an X-ray CT system, by suspending the tension test several times and carefully resetting the specimen in the test apparatus each time until final failure. Micrographs of polished section of damaged specimens revealed the damage states. The damage initiation and accumulation process strongly depended on specimen size as well as notch size. Interesting coupling behavior of defects involving, for example, matrix cracks, delamination, and fiber breakages were observed. Kinking failure in 90° layers was found along ±45° inclined matrix cracks tangent to the notch end in neighboring ±45° layers.

Keywords:

• laminates
• damage
• notch
• strength
• stress concentration
• volume effect

Acknowledgements

This paper is based on a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the New Energy and Industrial Technology Development Organization [P15006].