Aircraft structures require high safety and reliability in relation to flight. Therefore, analysis and evaluation of fatigue load durability and damage tolerance are required in the development process considering airworthiness.
The sensor pod, which is mounted outside the aircraft and performs its tactical mission, also requires structural safety and fatigue durability against the expected load history during the operational life cycle. Especially, the fatigue phenomenon of the structure due to various loads repeatedly generated according to the mission during the flights or flight has a great influence on the damage of the airborne structure, so fatigue life analysis from the design stage is necessary.
In general, the prediction of the fatigue life of an aircraft structure is known to be relatively accurate using a time-domain fatigue life prediction method using a stress spectrum developed based on the operating history of an actual aircraft.
However, in the case of mission equipment such as sensor pods, fatigue life prediction in the frequency-domain applying dynamic vibration condition is more general considering the efficiency of fatigue analysis. In this fatigue analysis in frequency domain, it is difficult to comprehensively apply the actual flight loads, so a complementary method considering the effects of typical loads is needed.
In this thesis, the fatigue life prediction method based on static and dynamic loads is newly proposed considering the complex aircraft loads and compared with the previous methods. In addition, fatigue life of sensor pod was analyzed under three conditions: endurance vibration condition, Buffett vibration condition, and the combined loads condition of the performance vibration and Maneuver loads. As a result, the fatigue life of the sensor pod was shown to meet the required fatigue life under the three major load conditions.