Fracture Toughness Testing

Fracture toughness testing, such as crack tip opening displacement (CTOD) measures the conditions under which an existing crack in a material will extend. CTOD is usually performed on materials that exhibit plastic deformation prior to failure. During a fracture toughness test, a specimen with a fatigue induced pre-crack is subjected to an increasing tensile load to failure. By measuring the load and displacement as the crack lengthens, the material’s resistance to further crack extension is determined.

Since the occurrence of flaws is typically not avoidable, fracture toughness is an important material property. Flaws, such as cracks, voids, inclusions, weld defects or material folds may act as stress concentrators to initial a subsurface crack. CTOD testing is valuable in determining whether there is a danger of catastrophic failure when a flaw is discovered in an existing structure.

fracture toughnes 01
fracture toughness 02
fracture toughness 03
  • Temperature between -40° F and +500° F
  • Bend type fixturing
  • ASTM E399
  • ASTM E1820