A Damage Tolerance/Life Processor For Structural Integrity And Force Management

Aging aircraft often experience fatigue problems after accumulating a considerable amount of flight time. In rotorcraft, this phenomenon can be accelerated due to high cycle loading conditions generated by the rotor systems. With continued use, it becomes ever more important to maintain them with proper force management techniques. In addition to high time usage, often the evolution of the configuration results in aircraft having inspection intervals and component retirement times much shorter than the original design. When an aircraft was not designed with damage tolerance in mind, it can be very difficult to properly maintain by a simple adjustment to its current procedures. A useful tool would be one that can rapidly determine inspection intervals or new retirement times for critical components as the aircraft changes configuration or performs new missions. This paper presents an architecture for a computer program to do damage tolerance analysis and life calculations. It describes the role of usage monitoring, flight loads surveys, and full scale test validation, in addition io analytical methods to predict loads and fatigue behavior. Such a tool will enable military services or commercial users to efficiently adjust force management practices to meet the changing environment of their fleet. Aircraft can be managed on an individual or squadron basis under peacetime and wartime conditions. Although there are many challenges and much test and analytical work to do to create a viable working program, the finished product will add a capability to logistical maintenance never before utilized.