Study on Fatigue Prediction of Composite Seaplane Float Based on The Porpoising Model Test Data

Abstract

Amphibious aircraft as an alternative mode of transportation to accelerate connections between small islands without building ground runway infrastructure. Amphibious aircraft floater is one of the important technological components that supports aircraft takeoff at sea. For that reason, the floater must be designed that is strong, effective and safe in the operation of amphibious aircraft. In this paper, the prediction method begins with selecting the heave and pitching data from the model test when float model experienced porpoising. These data is then used to calculate those coupled forces that act on the float structure which made from composite material. By knowing those forces the principal stresses that act on the structure also can be calculated. Therefore the stress time history on the float structure can be obtained. This stress time history is then applied to Palmgren – Miner formula that based on SN-Curve of the composite material to predict the life of the composite float. From this study it is found that the fatigue life of the floats is approximately 11 years with the assumptions of the seaplane experiencing takes off 4 hours daily.