Method for measuring fracture toughness of brittle media

摘要

A method for measuring fracture toughness of a brittle material is described which comprises the steps of impacting a sample of the material of preselected thickness and predetermined density and characteristic ultrasonic wave velocity Ci at preselected velocity with a projectile of material having a known density and characteristic shock impedence corresponding to a predetermined characteristic ultrasonic wave velocity, determining the stress sigma at which the sample fractures upon impact of the projectile, and determining the fracture toughness of the sample as equal to 2 sigma (cit/ pi )1/2, where t is the calculated time duration of a tensile pulse traveling the thickness of the sample.