Cup and Cone Fracture

The type of fracture in which the exterior portion is extended and the interior is relatively depressed, resembling a cup. It is often seen in tensile test specimens of a ductile material where the central portion undergoes plane-strain fracture and the surrounding region also undergoes plane-stress fracture. It is also seen when failure occurs due to separation at a central burst. Note: it is important to verify the reason for failure because correcting for tension failure may increase the tendency for central bursting.