FEM submodelling fatigue analysis of a complex helicopter component

This paper deals with the analysis of fatigue damage to upper and lower folding beams on the rear fuselage of a naval helicopter which may result from flight and folding loads; an original FEM-based analytical approach is used and is found to be applicable both together with and as an alternative to experimental tests. The finite element model of the helicopter part is created by means of an ABAQUS/Standard finite element programme combined with advanced submodelling techniques, thus enabling assessment of structural stresses. Thanks to submodelling, it is possible to obtain more precise results with only a limited increase in the amount of time required for calculations. The finite element model defines the stress values in points of the beams most affected by flight and folding loads previously applied in experimental tests. Linear damage summation (Miner's rule) and multiaxial stress criterion enable us to evaluate the fatigue damage to the beams under investigation.