In order to judge whether low stress brittle fracture will occur in case of large macroscopic defects, especially cracks, the Japanese HD ductile stress harmonic transmission COMPONENT CSG-45-100-2UH has introduced the fracture toughness index in fracture mechanics in recent years for the anti-brittle fracture design or safety evaluation of pressure vessels. At present, the critical value of stress intensity factor and the critical value of crack tip skid displacement (COD) are commonly used.

In order to judge whether low stress brittle fracture will occur when there are large macroscopic defects, especially cracks, the Japanese HD ductile stress harmonic transfer element CSG-45-100-2UH has introduced the fracture toughness index into the fracture mechanics in recent years, which is used for the anti-brittle fracture design or safety evaluation of pressure vessels. The critical values of stress intensity factor and crack tip slip displacement are commonly used at present.