Applications of the Equivalent Initial Quality Method

Abstract : For existing Air Force aircraft, damage tolerance and life assessment programs have been and are currently being conducted. The objectives of these programs are to define operational limits and to provide any necessary modification or operational usage options. The operational limits involved include: (1) an economic repair limit which specifies the opportune time for repairs, and modifications before such repairs and modifications become too expensive; (2) an inspection interval which provides the opportune time for detecting damage by NDI techniques before the damage reaches critical proportions; and (3) a fracture limit which provides the time at which an aircraft failure potential is believed to exist if no inspection and/or repair is accomplished. These analytically predicted operational limits are based upon the assumption that initial flaws exist in the airframe due to material and structural manufacturing and processing operations.