PREDICTING THE LIFE OF MILITARY VEHICLE COMPONENTS IN THE PRESENCE OF DEFECTS

When the components of a military vehicle are designed, consideration is given to long term durability under repeated mission applications. In reality, surface and subsurface defects have always existed in weldments, forgings, and castings. These defects came from the manufacturing process or nucleated during the life of the vehicle. These defects may grow under repeated operations, resulting in ultimate failure of parts well before the design life is achieved. In such situations, a design based on crack initiation alone will not suffice, and a fracture mechanics based fatigue should also be included to predict the design life of a part accurately. In this paper a methodology is given on how to predict the available design life given the presence of defects in different parts of a military vehicle. An example will be provided with the process to demonstrate each step of the process.