On how pseudo-ductility modifies the translaminar fracture toughness of composites and the nominal strength of centre-cracked specimens

Abstract

Among the efforts to revert the traditionally brittle characteristic of laminated composites, pseudo-ductility relies on utilising hybridisation to stimulate sub-critical damage mechanisms. However, how such pseudo-ductility would translate into an increase in material toughness or an improvement in the strength of the sub-components remains unclear. To elucidate this, we perform a numerical study departing from a parameterised pseudo-ductile model implemented in a finite element model. We use non-dimensional analysis to investigate the effect of the two most relevant parameters: pseudo-ductile strain (ɛd) and the ratio of ultimate strength to pseudo-ductile yield strength (of/oy). We infer material toughness from the simulation of Compact Tension specimens, and it is shown to increase linearly with ɛd, and non-linearly with of/oy but tends to a plateau. Then, the simulation of Centre Cracked scaled specimens reveal that the nominal strength increases on the elastic limit extreme (large specimens) but decreases below a given size