Random glass mat reinforced thermoplastic composities. Part VII: A statistical approach to strength

Abstract Large macroscopic‐scale variations in the tensile moduli and tensile strengths are charcteristic of random glass mat composites (GMT). The large‐scale, point‐to‐point variations in the local stiffness is characterized by a probability density function that can be used to predict the stiffness of parts only in a statistical sense. Weibull statistics widely used for modeling the scatter in the strength of brittle materials cannot be applied to the large variations in the strength of GMTs: The macroscopic stress field in brittle materials is assumed to be deterministic, while the stress field in GMTs varies randomly on a macroscopic scale. A statistical approach for characterizing the strength of GMTs is developed by combining an empirically established strength‐modulus correlation with the statistical characterization of the tensile modulus.