Effects of Crack Size on Crack Propagation Behavior and Experimental Verification of Cyclic Fatigue Mechanism of Sintered Silicon Nitride

Role of Grain Bridging Degradation of Small Crack on Crack Propagation Behavior in Polycrystalline Alumina Under Cyclic Load

“…Furthermore, we evaluated the bridging effect of artificial small cracks, and the cyclic fatigue mechanism in ceramics was discussed using the net stress intensity factor KIitp. Fatigue tests were carried out by an electromagnetic bending fatigue testing machine [17] in a chamber at 25 and 60% relative humidity. Cyclic fatigue tests under a sinusoidal wave-form with stress ratio R of 0.1 and frequency f of 60Hz, and static fatigue tests were performed.…”

“…Cyclic fatigue tests under a sinusoidal wave-form with stress ratio R of 0.1 and frequency f of 60Hz, and static fatigue tests were performed. The change in crack length 2a' during fatigue tests was measured using a metallographic microscope with a stroboscope and the crack depth c' corresponding to 2a' was determined by a graphic simulation [17]. The stress intensity factor was calculated by Newman-Raju's equation [21] into which the measured 2a' and estimated c' values were substituted.…”

Cerâmicas dentárias à base de ZrO2, aditivadas com biovidro: processamento, caracterização estrutural e mecânica

“…Um material frágil estará sujeito a falha mecânica para valores de solicitação cada vez menor, à medida que for submetido a trabalho (ANUSAVICE, 2005 (FREI, 1991;WEDDIGEN, 1992;KAWAKUBO, 1987;UENO;JACOBS, 1994). As relações entre os mecanismos que aumentam a tenacidade à fratura e mecanismos de fadiga cíclica vêm sendo discutidas, desde os anos 90.…”