Abstract In this study, experimental tests and a statistical analysis are conducted to verify the size effects associated with length on the tensile behavior of dry unidirectional carbon fiber sheets (DUCFS). As a statistical method, the two-parameters Weibull theory is considered. To verify the validity of the Weibull theory, four sets of direct tensile test were made on DUCFS specimens having different lengths. The direct tensile tests consist to evaluate the size effects associated with length on the mechanical properties of DUCFS such as tensile strength and the Young's modulus. The experimental results show a size effect of length on the tensile strength of DUCFS. Indeed, the tensile strength decreases when increasing the specimen length. In addition, the experimental results demonstrate that there is no size effect on the failure mode and on the Young's modulus of DUCFS. Finally, Weibull weakest link theory is used to predict the tensile strength size effect on DUCFS specimens. A good agreement was shown between the test data and predicted results obtained using the Weibull weakest link theory.

中文翻译：

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尺寸对干单向碳纤维板拉伸性能影响的威布尔统计分析和实验研究

摘要 在这项研究中，进行了实验测试和统计分析，以验证与长度相关的尺寸效应对干单向碳纤维板 (DUCFS) 的拉伸行为的影响。作为一种统计方法，考虑了双参数威布尔理论。为了验证威布尔理论的有效性，对不同长度的 DUCFS 试样进行了四组直接拉伸试验。直接拉伸测试包括评估与长度相关的尺寸对 DUCFS 机械性能（例如拉伸强度和杨氏模量）的影响。实验结果显示了长度对 DUCFS 拉伸强度的尺寸效应。事实上，当增加试样长度时，拉伸强度会降低。此外，实验结果表明，DUCFS 的失效模式和杨氏模量没有尺寸效应。最后，Weibull 最弱链接理论用于预测 DUCFS 试样的抗拉强度尺寸效应。测试数据与使用威布尔最弱链接理论获得的预测结果之间显示出良好的一致性。