Three mechanisms have been proposed for the recently observed failure waves (fronts) in plate impact experiments on silicate glasses. The first based on the phase transformation in glass does not explain the observed features in measured wave profiles. The second involves the comparison of the transfer of elastic shear strain energy in glass specimen due to 1-D compression to dilatant strain energy as a result of microcracking. No simulations of wave profiles were performed using this mechanism. The third is based on the microcracking multiple-plane model and is very rigorously derived. Numerical simulations of the measured wave profiles were carried out following the model. The simulations show that the failure wave phenomenon can be modeled by propagating surfaces of discontinuity from the specimen surface to its interior. Lateral stress increase and reduction of spall strength behind the failure front are successfully predicted by the multiple-plane model. Numerical simulations of high strain rate pressure shear experiments indicate the model predicts reasonably well the shear resistance of the material at strain rates as high as 1 · 106 m/s. The agreement is believed to be the result of the capability of the model in simulating damage-induced anisotropy. By examining the kinetics of the failure process in plate experiments, it is shown that the progressive glass spallation in the vicinity of the failure front and the rate of increase in lateral stress are more consistent with a representation of inelasticity based on shear-activated flow surfaces and microcracking, rather than pure microcracking. In the former mechanism, microcracks are likely formed at a later time at the intersection of flow surfaces.
|Original language||English (US)|
|Number of pages||26|
|Journal||Chemical Physics Reports|
|Issue number||1-2 SPEC. ISS.|
|State||Published - Dec 1 1998|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics