Weibull statistical analysis and experimental investigation of size effects on tensile behavior of dry unidirectional carbon fiber sheets

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.