Analytical and numerical studies of fracture and fatigue in ceramic materials

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6170745

Brockenbrough, J R

Constitutive and computational models were developed for two microstructural mechanisms which are active in many brittle materials; microcracking and martensitic transformation. A framework is presented for a general theory or cyclic compression fracture in brittle solids. Crack tip microcracking process zones have been proposed as a fracture mechanism in polycrystalline ceramics. An analysis is presented next which seeks to derive the ratio of dynamic to static fracture toughness values in microcracking brittle solids. The results are compared with experimental results of quasi-static and dynamic fracture initiation toughness for polycrystalline ceramics. At high temperatures, a theory for creep by interfacial flaw growth in ceramics and ceramic composites is presented based on a model of a deteriorating elastic solid. The predicted dependence of elastic creep strain rate on the far field stress, the progression of damage and the consequent reduction in elastic moduli, overall creep ductility, and implications pertaining to microstructural and temperature effects on creep are found to be in accord with a wide variety of experimental observations for ceramic and ceramic composites.

• Research Organization: Brown Univ., Providence, RI (United States)
• OSTI ID: 6170745
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CERAMICS
CRACK PROPAGATION
CREEP
CRYSTAL STRUCTURE
DUCTILITY
ELASTICITY
FATIGUE
FRACTURE PROPERTIES
HIGH TEMPERATURE
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MICROSTRUCTURE
TEMPERATURE EFFECTS
TENSILE PROPERTIES