The Numerical Simulation Of Inner Curing Process For Composite Cylinder

Developers had already started to replace metal vessels with fiber-wound composite cylinders with metal liners as the need of cylinders tends to light quality.Composite offer several advantages,such as big specific stiffness,high specific strength,and shaping easily,which makes composite cylinders have better performance over metal cylinders.At present,the evolution of composite vessels is constricted by their cost and the molding quality.The methods used to mold composite vessels include internal in-situ heat-curing and external heatcuring.During external heat-curing,the composite vessel is placed into a curing oven and the wound layers are heated according to a given heating process to solidify the composite.This internal in-situ heat-curing involves heating a mandrel such that the heat is transferred to the composite vessel,with curing being achieved based on the metal liner of the shell.The bubbles generated during the curing reaction can be successfully eliminated,such that composite vessels are of better quality and performance.Besides,the processing method which the shell is wond and cured in a same equipment offers a higher level of molding efficiency.This paper describes the in-situ curing of such vessels,using compressed air to heat the liner of a vessel and realize the curing and molding of the vessel.In the case of a composite vessel with a head that is heated by inserting a core tube,even heating cannot be achieved.Therefore,this study examined the use of a heating gasbag with small holes that is inserted into the metal liner during the heating process.The molding device and principle of the process are firstly introduced in the paper.The curing of the composite vessel,which incurs an exothermic chemical reaction and heat conduction,is a complex coupled process.The composite vessel will exhibit deformation during curing.In order to analysisabove changing process,a heat conduction model,curing kinetics model,and strain model are all addressed as part of this study according the nature of curing process.Then the finite element method(FEM)of composite cylinder is built.To study the laws governing changes in the curing temperature,the curing degree,and the deformation of a composite vessel during the curing reaction,a simulation program is developed using and the APDL language on an ANSYS software platform.Meanwhile,the influence of the room temperature,surface convection coefficient,fiber volume fraction,thickness of the composite vessel,and the material used for the metal liner on the parameters mentioned above is also analyzed to understand curing process better.Some results are obtained by the research of the paper.During the curing,heat is gradually transferred from the internal layer to the external layer such that the composite vessel cures from the inside layer,outwards.After the completion of the curing,the composite vessel shell shrinks inwards.The curing temperature,curing degree,and amount of deformation of the composite vessel are influenced,to various degrees,by the room temperature,surface convection coefficient,fiber volume fraction,and thickness of the composite vessel.The material used for the metal liner has little influence on the curing.