Sr. Choi et Ja. Salem, PRELOADING TECHNIQUE IN DYNAMIC FATIGUE TESTING OF CLASS AND CERAMICSWITH AN INDENTATION FLAW SYSTEM, Journal of the American Ceramic Society, 79(5), 1996, pp. 1228-1232
The solution of fatigue strength as a function of preloading in dynami
c fatigue testing was obtained numerically for an indentation flaw sys
tem. The dynamic fatigue strength is dependent on preloading and fatig
ue parameter (n). The effect of preloading on dynamic fatigue strength
decreases with increasing fatigue parameter: for n greater than or eq
ual to 20 the effect is negligible up to a preloading of 90%. The solu
tion was verified by dynamic fatigue experiments conducted with soda-l
ime glass and alumina specimens with as-indented flaws in room-tempera
ture distilled water. The result indicates that one can apply a preloa
ding corresponding up to 90% of fatigue strength for most glass and ce
ramic materials with no change in fatigue strength, resulting in a dra
matic saving of testing time.