Various methods to measure fracture toughness using in‐dentation precracks were compared using soda‐lime glass as a test material. In situ measurements of crack size as a function of applied stress allow both the toughness K c and the residual‐stress factor χ to be independently determined. Analysis of the data showed that stress intensity factors based on classical half‐penny crack shapes overestimate toughness values and produce an apparent R ‐curve effect. This is due to a constraint on crack shape imposed by primary lateral cracks in soda—lime glass. Models based on elliptical cracks were developed to account for the crack‐shape effects.
No takes yet. Share an insight, caveat, or question.
Smith et al. (1992) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: