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Thermal Activation Effects inCrack Propagation and Reliability of Fused Silica



Robert F. Cook


The thermal activation energy u1 characterizing changes in crack velocity with temperature for fused silica in water is determined. The determination is based on a new analysis that incorporates the familiar Arrhenius term for thermally activated processes and a term characterizing the departure of the propagating crack system from fracture equilibrium. In determining u1 from experimental data the Arrhenius term and the non-equilibrium term are of approximately equal magnitude. The analysis is applied to an extensive compilation of crack velocity measurements in fused silica to arrive at an estimate of u1 = (69 ± 11) kJ mol1, where the value represents the multi-laboratory mean ± variability. This value is greater than that assumed in some earlier works and characterizes a within-laboratory maximum increase in crack velocity of a factor of approximately 102 in fused silica between freezing and boiling water conditions and a decrease of a factor of 103 in component time to failure for the same change in conditions. The multi-laboratory variation in velocity at fixed temperature is comparable to the within-laboratory maximum increase, perhaps obscuring temperature effects.
Journal of the American Ceramic Society


thermal, fracture, fused silica, reliability


Cook, R. (2019), Thermal Activation Effects inCrack Propagation and Reliability of Fused Silica, Journal of the American Ceramic Society, [online], (Accessed April 21, 2024)
Created June 21, 2019, Updated October 14, 2022