R. Banerjee et Bk. Sarkar, CRACK INITIATION BY INDENTATION FATIGUE IN LEAD ALKALI AND SODA-LIME GLASS, Journal of the American Ceramic Society, 80(10), 1997, pp. 2722-2724
An indentation technique using a conventional Vickers microhardness te
ster was used to evaluate fatigue properties of lead-alkali and soda-l
ime silica glasses. The specimens were indented repeatedly at the same
point with subcritical loads until radial cracks were initiated. The
number of cycles to initiate the cracks at different subcritical loads
demonstrated typical fatigue curves for both glasses. The uniqueness
of the experiment was that the diagonal lengths of the deformed cavity
were observed to increase with the number of cycles. This increase of
the deformed cavity for a certain number of cycles prior to the visib
ility of crack initiation was analyzed, correlating the elastic-plasti
c phenomenon and the accumulation of the residual stress in each cycle
.