Prediction of Tensile Strength of Unidirectional CFRP Composites

The tensile strength of unidirectional carbon fiber-reinforced plastic (CFRP) composites was predicted by numerical simulation plus size scaling. The fiber strength distribution used in the numerical simulation was determined from the fragmentation process in a single fiber composite. Since the experimental data obviously did not fit the normal Weibull distribution, we fitted them with the Weibull of Weibull model, considering the statistical distribution of scale parameters of fiber strength in the normal Weibull model. Moreover, the constitutive law of the matrix was derived from the stress-strain curves of the angle ply laminates, utilizing the micromechanics approach proposed by Tohgo et al. [9]. Based on these parameters, we simulated the tensile fracture of unidirectional CFRP composites with the spring element model (SEM). The predicted tensile strength by numerical simulation plus size scaling agreed well with the experimental data. The results also confirmed that the Weibull of Weibull model is important to predict size-dependent composite strength. (C) Koninklijke Brill NV, Leiden, 2010