Spherical Cavity Expansion in Material with Densification

LLE Review, Volume 85 15 Introduction Fused silica (SiO2) exhibits some unique features when it is ground or polished. It also densifies permanently under large compressive stresses at room temperature;1–3 up to 15% permanent densification has been observed.2,3 The experimental data for densification from different works, however, are obviously inconsistent,4 which may result from different levels of shear stresses present in the experiments. The molecular dynamics simulation by Tse et al.5 proved this suggestion by showing that the densification is caused by extensive bending of atomic bonds, even under pure hydrostatic pressure. Based on these observations, a new constitutive law was suggested by Lambropoulos et al.6 for this kind of material.7