Impact induced transition from damage to perforation

TL;DR

This study models impact-induced damage in a heterogeneous bar, revealing a phase transition from damage to perforation with critical behavior and disorder effects.

Contribution

It introduces a simple model capturing the transition from damage to perforation and analyzes critical phenomena and disorder influence in impact fracture.

Findings

Transition from damage to perforation is analogous to a continuous phase transition.

Near the critical impact energy, the intact interface fraction approaches zero.

Disorder affects critical exponents, causing a crossover near the transition point.

Abstract

We investigate the impact induced damage and fracture of a bar shaped specimen of heterogeneous materials focusing on how the system approaches perforation as the impact energy is gradually increased. A simple model is constructed which represents the bar as two rigid blocks coupled by a breakable interface with disordered local strength. The bar is clamped at the two ends and the fracture process is initiated by an impactor hitting the bar in the middle. Our calculations revealed that depending on the imparted energy, the system has two phases: at low impact energies the bar suffers damage but keeps its integrity, while at sufficiently high energies, complete perforation occurs. We demonstrate that the transition from damage to perforation occurs analogous to continuous phase transitions. Approaching the critical point from below, the intact fraction of the interface goes to zero, while the deformation rate of the bar diverges according to power laws as function of the distance from the critical energy. As the degree of disorder increases, further from the transition point the critical exponents agree with their zero disorder counterparts, however, close to the critical point a crossover occurs to a higher exponent.