Particle modeling of dynamic fracture simulations of a 2D polymeric material (nylon-6,6) subject to the impact of a rigid indenter

This paper employs particle modeling (PM) for the simulation of dynamic fragmentation in a 2D polymeric material (nylon-6,6) subject to the impact of a rigid indenter. A new particle interaction scheme (nearest-second neighboring particle interaction) is raised in an attempt to eliminate a mesh bias in the direction of fracture propagation that a regular lattice model with uniform axial linkage possesses in common. The modeling results compare favorably with the according experimental observations, in terms of the impact load and energy profiles, the specimen deflection value at the peak of the load, and the eventual crack pattern. A mesh dependence problem of PM is discovered while using different mesh resolutions and preliminarily investigated. Furthermore, a number of investigations are conducted accounting for other parameters: (i) sharpness of indenter (flat, small or large curvature), (ii) different drop velocity of indenter, and (iii) microscale perturbation in the material's property. These investigations show that the dynamic response of the impact and the resultant fracture patterns are dependent on the material's constitutive property, the geometric shape of indenter, and the impact velocity.