We performed a forensic investigation on an injury from a forklift accident, which occurred due the failure of the parking brake to automatically engage.
After chemical and metallurgical evaluation was performed of the wire cable, it was determined that it had failed in fatigue, which initiated in two locations along its length. Fatigue is the progressive failure of a components subjected to repeated or fluctuating stresses below the yield strength of the material. These locations were likely where the cable passed over sheaths or pins. The left image above is photograph at 9x showing the cable fracture. The image in the center is at 20x showing some of the broken wire fracture profiles. The right image is at 150x showing an indentation in one of the broken wires.