Study On Bearing Capacity Of Offshore Floating Inflatable Membrane Structure

As a new type of lightweight material,the inflatable membrane has been widely used in the field of architecture and aerospace.It is light weight,rapid deployment,low cost,safety and reliability which has been used as exterior wall of famous buildings and bearing components of aeronautical airships and space antennas.Especially,in order to meet its special requirements of combat readiness and emergency rescue in the field of maritime military traffic,maritime rescue and disaster relief.A temporary structure with light weight,small reserve and transportation space and fast development is urgently needed.Floating inflatable membrane structure emerges as the time requires.In order to grasp the mechanical characteristics of floating inflatable membrane structure and explore the feasibility of engineering application,this paper focuses on the bending deformation characteristics and ultimate bearing capacity of the floating inflatable membrane structure.Relationships among internal pressure,diameter and bearing capacity of the floating inflatable membrane are obtaine by model test and theoretical analysis.The feasibility of using inflatable membranes to design floating bridges is explored.This paper fills the gap in the research field of floating inflatable membranes and it has important value to promote the development of floating inflatable membranes in marine engineering.The uniaxial tension experiments of membrane materials were carried out.The elongation,tear strength and stress-strain curves of the membrane materials in the longitude,weft and 45 degrees of longitude and weft were obtained.The stress-strain curves showed three stages: straight line-curve-straight line.It was found that the three direction elastic modulus was quite different,and the membrane material was anisotropic.The bearing capacity of inflatable membranes under simply supported conditions was studied.Three-point and four-point bending tests were carried out for several diameter and internal pressure inflatable membrane structures.The load-deformation law and wrinkle development process of inflatable membrane structures were obtained,and the influence of internal pressure on their bearing capacity was discussed.Based on energy principle and four-point bending test,the equivalent shear modulus G was obtained.The prediction formula of mid-span deflection of inflatable membrane was deduced.Compared with the experimental results and prediction formula,the accuracy of the prediction formula was verified.The bearing capacity of the floating inflatable membrane structure was studied.Based on the non-contact strain measurement system,the relationship between internal pressure and strain was studied.It was found that it was a linear positive correlation,and when the variation of internal pressure was small,the inflatable velocity had little effect on strain.The bending test of the inflatable membrane structure under hydrostatic boundary was carried out.The load-displacement law and wrinkle development process of the floating inflatable membrane structure were obtained.The displacement was decomposed into subsidence and deformation,and the effects of diameter and internal pressure were discussed respectively.Based on the theory of elastic foundation beam,the mid-span displacement of the floating inflatable membrane structure was predicted,its error factors and application scope were discussed by comparing with the test results.A new type of inflatable floating bridge was designed with inflatable membrane structures.Based on the prediction method of mid-span displacement of the floating inflatable membrane,the mid-bridge module has been checked.Based on the potential flow theory,the mooring force and motion response were checked,that prove the rationality and feasibility of the application of floating inflatable membrane structures in the design of floating bridges.