Wrinkling And Vibration Studies On Inflatable Membrane Structures

The thickness of the membrane structure is in microns. Owing to the membranestructure is always folded before inflation, wrinkles and vibration are easy to happenin the process of operation. Wrinkles which are the main defects of inflatedstructures will make the bearing capacity and surface accuracy of the structuresdown. Some special functions of inflated structures will be affected by vibrationand the entire structure even totally be damaged by resonance. Studies on thewrinkling behaviors and vibration of the inflatable membrane structures are of greatguiding significance on the prediction of wrinkles developing and expending, on theanalysis of the load-carrying capacity and on the control of vibration.A finite element model of standard inflated arch is established to makenumerical simulation on developing and expending of wrinkles. The carryingcapacity of the arch is also analyzed. The influence of pressure, load type, sectionradius and thickness of material on wrinkling load, wrinkling location andload-carrying capacity are considered. The experiment device is designed to carryout the bending experiment of inflated arch. The results in numerical simulation areverified by the experiment.Prestressed modal analysis and harmonic response analysis are carried outbased on the analysis of wrinkling characteristics. The top10of the naturalfrequencies, vibration modes and frequency-amplitude cures are obtained. Theinfluences of pressure, section radius and thickness of material on the naturalfrequencies and vibration modes are considered. The influences of the structureparameters of inflated arch and excitation parameters on frequency-amplitude curesare also analyzed. Wrinkle parameters are added to the model to make a comparisonon the vibration characteristics between wrinkled inflated arch and unwrinkled one.And then the influences of the extent and location of wrinkles on the naturalfrequencies, vibration modes and frequency-amplitude cures are analyzed.The bending and vibration analyzed are carried out on inflated wing and softairship based on the method of wrinkling and vibration analysis on the inflated arch.The bending, model and harmonic characteristics are analyzed for inflated wing.The influences of pressure, wingspans and wrinkling parameters on the naturalfrequencies, mode types and frequency-amplitude cures are analyzed. Finite elementanalysis of bending and vibration characteristics for soft airship are carried out. Thestiffness against bending, the top10of the frequencies, vibration modes and thefrequency-amplitude cures under two excitations of the airship are obtained.The law of wrinkles developing and expending, load-carrying characteristics, vibration characteristics and the influences of wrinkles on vibration of inflated archare studied in this paper. The method used for analysis of inflated arch are extendedto the analysis of wrinkling and vibration characteristics of inflated wing and softairship structure. The results in this paper are good references for the prediction ofload-carrying characteristics, the laws of wrinkles developing and expending and thecontrol of vibration for inflated structures.