Abstract To investigate the effect of notches on static and fatigue properties of T800 fabric carbon fibre reinforced epoxy, comparative tests were conducted between specimens of three depths of notches and un-notched specimens. Results demonstrate that the residual tensile strength of specimens is linearly decreased with the increasing depth of notches from 2mm to 4mm. The tensile strength on notched specimens dropped 31.5% comparing with no-damaged laminate. Due to the effect of notches, the fatigue limit was reduced to 55% of UTS and the slope of the S-N curve tends to be horizontal. In-situ damage expansion process was observed and the shape of proposed normalized S-N curves could be explained and concluded as two stages: the first stage accounts for 20% of the fatigue life, showing a dramatic decrease of fatigue strength; the remaining stage takes up the rest of the total life span, representing a steady decline in strength. It shows that no-damaged and notched laminates exhibit different behaviours in terms of damage evolution.

中文翻译：

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缺口对T800织物增强复合材料静力和疲劳性能的影响

摘要 为研究缺口对T800织物碳纤维增强环氧树脂静态和疲劳性能的影响，对三种深度缺口试样与无缺口试样进行对比试验。结果表明，随着缺口深度从2mm增加到4mm，试样的残余拉伸强度呈线性下降。与未损坏的层压板相比，缺口试样的拉伸强度下降了 31.5%。由于缺口的影响，疲劳极限降低到 UTS 的 55%，SN 曲线的斜率趋于水平。观察原位损伤扩展过程，提出的归一化SN曲线的形状可以解释和总结为两个阶段：第一阶段占疲劳寿命的20%，疲劳强度急剧下降；剩下的阶段占据了总寿命的剩余时间，代表实力稳步下降。它表明未损坏和有缺口的层压板在损坏演变方面表现出不同的行为。