Mesoscale Phase Field Modeling of Glass Strengthening Under Triaxial Compression

Recent “hydraulic bomb” and “confined sleeve” tests on transparent armor glass materials such as borosilicate glass and soda‐lime glass showed that the glass strength was a function of confinement pressure. The measured stress–strain relation is not a straight line as most brittle materials behave under little or no confinement. Moreover, borosilicate glass exhibited a stronger compressive strength when compared to soda‐lime glass, even though soda‐lime has higher bulk and shear moduli as well as apparent yield strength. To better understand these experimental findings, a mesoscale phase field model is developed to simulate the nonlinear stress versus strain behaviors under confinement by considering heterogeneity formation — under triaxial compression and the energy barrier of a micro shear banding event (referred to as pseudo‐slip hereafter) in the amorphous glass. With calibrated modeling parameters, the simulation results demonstrate that the developed phase field model can quantitatively predict the pressure‐dependent strength, and it can also explain the difference between the two types of glasses from the perspective of energy barrier associated with a pseudo‐slip event.