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Effects of Damage on Thermal Shock Strength Behavior of Ceramics
Author(s) -
Jin ZhiHe,
Mai YiuWing
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08903.x
Subject(s) - residual strength , thermal shock , materials science , composite material , fracture mechanics , ceramic , fracture toughness , flexural strength , softening , bridging (networking) , toughness , damage mechanics , fracture (geology) , strength of materials , structural engineering , finite element method , computer network , computer science , engineering
When subjected to severe thermal shock, ceramics suffer strength degradation due to the damage caused by the shock. A fracture‐damage analysis is presented to study the effects of damage on the thermal shock behavior of ceramics. It is assumed that a narrow strip damage zone is developed at the tip of a preexisting crack after a critical thermal shock and the damage behavior can be described by a linear strain‐softening constitutive relation. Damage growth and strength degradation are determined based on fracture and damage mechanics. Numerical calculations are carried out for two ceramic materials, and the strength degradation agrees quite well with experimental results. The effects of bridging/damage stress, the fracture energy of the bridging/damage zone, and specimen size on thermal shock strength behavior are studied. A higher fracture energy can enhance the residual strength of thermally shocked ceramics and, for a given fracture energy, a higher bridging stress is needed to reduce the strength degradation. It is also shown that the thermal shock strength behavior is size‐dependent, and a high value of ( K IC /O b ) 2 , where K IC is the intrinsic fracture toughness and O b is the bending strength, can improve significantly the residual strength.