Vibration characteristic analysis and experiment of non-rigid airship with suspended curtain

Abstract

In order to evaluate the vibration characteristics of non-rigid airship with suspended curtain, we introduce vibration characteristic analysis method of the inflatable membrane structure. Modal numerical method of the inflatable membrane structure under the pressure difference is validated by the model testing of the inflatable cantilever tube. The finite element model of 75m airships is established to simulate the vibration characteristics subjected to only pressure difference and the resultant force of weight and buoyancy. The nonlinear static deformation and stress analysis are investigated for two kinds of equilibrated configurations with various pressure differences, as well as the vibration characteristics. The structural efficiency of the suspended curtain is investigated through the force transfer ratio at the assumed equilibrated point. The effects of manufacture error of the suspended cable length on the structural behavior are analyzed. The results indicate that the local area of airship envelope connected to the suspended cable is a weak part. Various pressures and pressure gradients have significant effects on the global airship structure and the suspended curtain. The suspended curtain is effective to transfer the equilibrated force from the bottom to the top of airship envelope. Manufacture error of the suspended cable length could result in obvious deformation of local airship envelope. The presented work is valuable to the structural engineering design of stratospheric airship.