Metallurgical failure analysis of a horse trailer: A criminal investigation

Following the deaths of three people involved in a vehicular collision with an ejected horse, criminal charges were brought against the horse’s owner. Failure analysis was performed on the horse’s trailer to determine its roadworthiness. The failure mode of the hinge between the door and frame became the focus of the investigation. The analysis concentrated on proving whether or not the hinge was broken prior to the collision; that the trailer was not roadworthy; and whether the trailer was capable of safely transporting two horses on a public freeway. Analysis using optical microscopy and the scanning electron microscope indicated the hinge was significantly corroded and mechanically deformed. Additionally, there was evidence of paint on an alleged fresh fracture surface. The results were presented at the trial of the defendant.