Modification of nominal strength scaling laws to pseudo-ductility

Abstract

We investigate the influence pseudo-ductility has on the notched strength and size-effect behaviour of typical notched specimens of quasi-isotropic pseudo-ductile composite materials. Our previous findings reveal that pseudo-ductility enhances translaminar toughness and nominal strength recovery but can negatively affect specimens below a critical notch size. The traditional Bažant Size Effect Law (SEL) does not adequately capture these observations, necessitating modifications to account for the non-recoverable pseudo-ductile damage past the pseudo-yield strength. We propose modifications to the nominal strength scaling laws, aiming to characterise both the notched strengths for a given notch radius and the size effect due to pseudo-ductility. Modifications are applied to centre-cracked (CC), elliptical hole (EH), and open-hole (OH) specimens for a wide range of pseudo-ductile materials. The proposed modifications for nominal strength predictions agree with FE estimates across all three notch shapes (CC, EH, and OH). The findings suggest that the presented SEL serves as a valuable tool for understanding and assessing the size-effect behaviour of pseudo-ductile composites.