Aerostat Dynamic And Vibration Analysis

Based on the aerostat fly process,simulated the movement characteristics of the airship and vibration characteristics of the nacelle under stable state.Combined with actual situation,this paper study the aerostats movement characteristic and vibration characteristic of anchorage condition systematacially combining with the fact that few institutions research it in our nation.In this paper,we carried out the following research work:(1)Aerostat movement characteristics calculationAerostat space six degrees of freedom movement model is established based on the Newton’s Laws and momentum theorem and moment of momentum theorem.The motion characteristics of Aerostats are calculated separately under the ideally condition,constant wind interference condition and wind interference condition.Numerical simulation analysis has been done through the Matlab software.(2)Pod structural vibration characteristics calculationPod structure vibration analysis model is established based on the finite element theory.pod finite element model is connected on the aerostat in the form of hinge joint.Load excitation are aerostats force of the structure of pod.Calculating natural frequency,modal vibration mode and some other related parameters of the Pod structure through the ANSYS software.And using the modal superposition method for dynamic response calculation.Through the above research,this article mainly have the following conclusion:(1)When aerostat free lift-off under windless and constant wind condition,aerostat is stable in space,the vibration amplitude is very small which can be neglected.However it comes to the gust disturbance,aerostat shocks within a small range of the airspace with the gust disturbance.(2)Aerostat balance position is directly above the initial launch point in the ideal state.In the case of wind disturbance,the balance position will shift along the direction of the wind,and the offset distance will increase if wind increase.(3)In the ideal state,aerostats have minimum pitching Angle under the stable state,and the pitching angle will increase with the wind speed increase.(4)Pod structure vibration in windless condition and constant wind condition is very small which can be neglected.Vibration can not be ignored in the condition of gust,and it changes with the change of wind speed.