RATE-SENSITIVE MICROMECHANICAL DAMAGE MODEL FOR BRITTLE SOLID

A micromechanical damage model for a brittle solid capable of taking i nto account the effect of high loading rate (in the form of stress-rat e) is presented. Although, this model is applicable to any particulate brittle solid, concrete is given primary consideration. An existing s elf-consistent rate-insensitive model is modified and extended to indu ce rate dependency of concrete type material with preexisting damages (cracks). The variations of several fracture mechanics parameters of s olid, viz., stress intensity factors, fracture toughnesses, etc., unde r the influence of high loading rates were given primary consideration . The process of crack evolution in a particulate cracked solid under tensile and compressive stress-field has been thoroughly considered al ong with all possible situations that may arise. Crack kinking and nuc leation are considered for both tensile and compressive stress-field. The resulting rate-sensitive micromechanical damage model has been cod ified and several experiments have been replicated to validate it.