Fracture toughness (K_Ic) is an intrinsic material property that defines how well a material resists fracture. The standardized testing methods for K_Ic involve creating a small crack in a fracture toughness test specimen and propagating the crack under an applied load.

Examples of standardized methods for ceramics and brittle materials include: the chevron-notched beam (CNB), single-edge precracked beam (SEPB), and the surface crack in flexure (SCF) methods.¹