INDENTATION-CYCLING TESTS ON SODA LIME GLASS

Repeated indentation loading produces lateral-crack-controlled chippin g in brittle materials. This has been investigated in soda-lime glass for a load-cycling range P(min) < P(max) less-than-or-equal-to P, wher e P is the indentation load. Extensive chipping damage occurs after a critical number of cycles for P(max) = P and P(min) = 0, whereas subcr itical cycling with P(min) > 0 suppresses the failures. This is consis tent with an environmental interaction. Postcycling aging can produce delayed chipping, and the response depends upon the load-cycling histo ry.