Research On Fatigue Strength Of The Special Local Structure Of The Aluminum Alloy Hovercraft

As a special high-performance ship type,the aluminum alloy hovercraft uses a large number of aluminum alloy sheets for its operation mode and purpose,and this structure is also more special than conventional ship types,mainly reflected in the rigid airway deck and propel the nacelle.The airway deck is in contact with the air cushion and it’s composed of bolted aluminum alloy sheets and stiffeners.The propulsion nacelle is equipped with a propulsion main engine,which is mainly composed of a cylindrical thin-walled enclosure and reinforcing ribs.When the hovercraft sails at high speed,the air cushion,and the propeller blades will generate high-speed airflow.Therefore,these two special structures will be subjected to alternating loads caused by the airflow for a long time,which is very likely to cause the bolt connection of the airway deck,and the thin-walled enclosure of the propulsion nacelle.The fatigue damage of these components is critical to the performance of the hovercraft.At present,there is insufficient research on the local special structural strength of these two aluminum alloy hovercraft at home and abroad.This paper aims at two special structures that are prone to fatigue problems: the bolted connection of the airway deck and the thin-walled enclosure of the propulsion nacelle.The main researches are as follows:1)Based on the structural response of a real ship,the bolted structure of the airway deck is numerically analyzed under various simulation methods;2)The fatigue test of the bolted structure of the airway deck is carried out,and the corresponding S-N curve and other parameters are obtained,so as to verify the rationality of the modeling method of the bolted structure and provide important parameters for the fatigue strength check of the airway deck;3)The research on the fatigue damage characteristics of the thin-walled enclosure of the nacelle caused by the vibration of the propulsion main engine and the air flow field of the propulsion propeller is carried out,which provides some guidance and suggestions for the fatigue analysis of the special structure of the nacelle.