FRACTURE PROCESS OF GLASS REVEALED IN LASER SHOCK WAVE EXPERIMENTS

摘要

Dynamic crack initiation in soda-lime glass was studied experimentally. The center notched disk specimen was loaded in the center by a laser of 500ps period with energy density of 10~(13) W/cm . As recorded by high speed framing camera, the crack tip divided in two branches at original precrack front with an angle between 104° ～ 110°. The crack propagation velocity was found to obey the terminal velocity theory obtained in conventional impact experiments. We also found that the defects in the glass were mobilized under shock loading. A simple microcrack simulation could illustrated the phenomena qualitatively.