The typical vision of a product failure is that of a device with a broken or fractured component. The location, shape, and microscopic features of a fracture provide a window into the history of that failure. Each particular fracture mode, i.e. overload, fatigue, or environmentally-assisted fracture, have characteristic physical features that distinguish one mode from another. The location of the starting point or origin of the fracture and its orientation reveal the direction of forces applied to the component. The physical characteristics of wear failures also provide direct evidence of the specific mechanism and causes of damage leading to the failure.

These characteristic features are sometimes visible with the naked eye, but often require high-magnification examination by scanning electron microscopy. Laboratory testing, including direct mechanical tests and evaluation of the material's structure, are used to correlate forces applied to the component with the material properties. Computer-aided stress analysis gives a quantitative picture of the how the material would be expected to behave in a particular application, and laboratory simulations are used to verify unexpected or indeterminant findings. (Pic- Loggin Chain Fracture)

Representative Mechanical Failure Investigations

• Fractured cervical vertebrae plate
• Failed wire bonds on PC boards
• Excessive wear of carbide valve seats
• Ruptured fire sprinkler fitting
• Fractured fasteners from highway signs
• Fractured railroad rails
• Cracked nylon water filter housing
• Buckled fiberglass ladder
• Fractured nylon pulley
• Premature wear of high-speed bearings