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.

中文翻译：

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缺口CFRP层压板在拉伸载荷作用下的失效行为

进行了一项实验研究，以确定带缺口的准各向同性碳纤维增强塑料 (CFRP) 层压板的拉伸失效机制。准备了三组试样来研究试样尺寸和应力集中因子对损伤开始、累积和最终破坏的影响。用X射线CT系统观察试件的损伤累积过程，通过多次暂停拉伸试验，每次小心地将试件在试验装置中复位，直到最终失效。损坏试样抛光部分的显微照片揭示了损坏状态。损伤开始和累积过程在很大程度上取决于试样尺寸和缺口尺寸。有趣的缺陷耦合行为，例如，基体裂纹、分层、并观察到纤维断裂。沿着与相邻±45° 层中的缺口端相切的±45° 倾斜基体裂纹发现90° 层中的扭结失效。