A metal fracture occurs when an applied force separates a metal into two or more pieces. Ductile metals undergo plastic deformation where they resist the fracture before eventually succumbing to the stress. Ductile fractures display several symptoms of plastic deformation before fracture. The fracture often breaks into two pieces and occurs slowly over time. Brittle fractures are sudden and often occur without symptoms. These fractures are predominant in large structures such as tanks, pipes, bridges, and box beams.