Damage evolution, localization and failure of solids subjected to impact loading

Abstract

In order to reveal the underlying mesoscopic mechanism governing the experimentally observed failure in solids subjected to impact loading, this paper presents a model of statistical microdamage evolution to macroscopic failure, in particular to spallation. Based on statistical microdamage mechanics and experimental measurement of nucleation and growth of microcracks in an Al alloy subjected to plate impact loading, the evolution law of damage and the dynamical function of damage are obtained. Then, a lower bound to damage localization can be derived. It is found that the damage evolution beyond the threshold of damage localization is extremely fast. So, damage localization can serve as a precursor to failure. This is supported by experimental observations. On the other hand, the prediction of failure becomes more accurate, when the dynamic function of damage is "tted with longer experimental observations. We also looked at the failure in creep with the same idea. Still, damage localization is a nice precursor to failure in creep rupture.

How does spallation microdamage nucleate in bulk amorphous alloys under shock loading?

“…It has revealed that in ductile fracture, spallation occurs via nucleation, growth, and coalescence of microvoids, 4,5 while in brittle fracture, spallation occurs via nucleation, growth, and coalescence of microcracks. 6,7 Although the mechanism of spallation in conventional polycrystalline alloys is understood, the mechanism of spallation in bulk amorphous alloys is unclear. As a relatively young class of alloy materials, bulk amorphous alloys [8][9][10] have many excellent physical and mechanical properties such as high strength and hardness due to their unique microstructure.…”

Trans-scale Coupling in Multiscale Simulations

“…Spallation is a typical process with coupled multiple space and time scales [13]. For the time-dependent damage process, which consists of microcrack nucleation and growth, Table 1 lists all parameters involved in the problem, with their corresponding dimensions L, T , and M are the notations of the dimensions of length, time, and mass, respectively.…”

“…(9). For more details of DFD, one can refer to Bai et al [13] and Davison and Stevens [15]. M , S, De, and De * are four dimensionless parameters, as introduced above.…”

A nonlinear threshold model applied to spallation analysis

“…These studies provide progressively helpful means to reveal the essence of spalling. In recent 10 years, some new and informative studies relevant to spallation are made to have deeper understanding of the process [7][8][9][10][11][12][13][14]. All these work intended to link the macroscopic spallation and the microdamage evolution inside materials.…”