On lateral cracks in glass

Abstract

The importance of lateral cracks in solid particle erosion of brittle materials has been confirmed as a result of a large number of previous investigations in this area. Even though the underlying mechanism of steady-state erosion of a brittle material is the formation and growth of lateral cracks, the surface morphology of the eroded material does not readily indicate this aspect. This has precipitated the need for a study of single impact events. This study concentrates on lateral cracks in glass produced by solid particle impacts. Single impacts are studied in terms of lateral crack extensions and their probability of chipping at two angles of impact of 20 and 90°. Comparisons between these two sets of data were made at the same normal component of velocity to clearly bring out behavioural differences at the two angles o of impact. Steady-state erosion results are then interpreted in terms of the above results obtained from a study of single impacts. There appears to be marked agreement between these results and experimental observations. The same trend was observed in strength degradation measurements. Increased chipping and lateral crack extensions in the 20° impact situation has been explained in terms of linear elastic fracture mechanics, as opposed to the plastic deformation mechanism proposed earlier. The importance of single impacts in the study of steady-state erosion of brittle materials by solid particle impact is well demonstrated by this study.[/p]