Meso-scale modeling of cohesive cavitation in polymer networks

Abstract

Cavitation influences the failure of elastomers and soft adhesives, but connecting its microscopic initiation to subsequent cavity growth remains challenging. Here, we develop a discrete mesoscale framework that combines finitely extensible, breakable strands with local van der Waals interactions to examine how cohesion and network heterogeneity transform distributed dilation into localized damage. In the simulations, local cohesive instability produces a network-scale precursor whose subsequent expansion is coupled to strand stretching and rupture. Cohesive strength and intrinsic defect size govern the critical hydrostatic tension, while cohesion also controls the number and spatial distribution of cavities. Under confined loading, decreasing the layer thickness promotes multiple cavities and distributed strand rupture, extending the load-bearing response and increasing the critical work density of rupture. An energetic interpretation based on the thickness dependence of the crack-driving force connects these observations to competition between additional cavity nucleation and propagation of existing damage. The results link local cohesive instability to the collective evolution of cavities and rupture in disordered polymer networks.