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, farther 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.

中文翻译：

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冲击导致的从破坏到穿孔的过渡

我们研究了异质材料的棒状试样的冲击诱导损伤和断裂，重点是随着冲击能量逐渐增加，系统如何处理穿孔。构建了一个简单的模型，该模型将钢筋表示为两个刚性块，这些刚性块由具有无序局部强度的易断裂界面耦合。杆的两端被夹住，并且通过撞击器在中间撞击杆来启动断裂过程。我们的计算表明，取决于所传递的能量，该系统分为两个阶段：在低冲击能量下，钢筋受损伤但保持其完整性，而在足够高的能量下，会发生完全穿孔。我们证明从损坏到穿孔的过渡类似于连续相变。从下面接近临界点，界面的完整分数变为零，而棒的变形率根据幂定律而变化，该定律是与临界能量的距离的函数。随着无序度的增加，临界指数离过渡点越远，与零无序对应数一致。但是，接近临界点时，会发生较高指数的交叉。