Strength Analysis Of Plastic Liner Fiber Winding Hydrogen Storage Cylinder

With the growing demand for clean energy,hydrogen energy,as clean energy with pollution-free emission,is increasingly favored by people,and the hydrogen storage cylinder is widely used in the field of new energy vehicles and aerospace has become the research focus of many experts and scholars.Plastic liner fiberwrapped hydrogen storage bottle(Type Ⅳ hydrogen storage bottle)has been mass-produced in the United States,Japan,Korea,and other countries,at present,the mainstream hydrogen storage cylinder in China is still aluminum alloy-lined fiber wound gas cylinder(type Ⅲ hydrogen storage cylinder).,and there is no relevant standard for type IV hydrogen storage cylinder liner with engineering plastics in China,it has not yet realized large-scale industrial application,therefore,there are relatively few researches on type IV hydrogen storage cylinders in China.This paper studies the following aspects based on the plastic liner fiber winding hydrogen storage cylinder:(1)The fiber layer thickness of the cylinder body and head section is predicted by the formula of the fiber layer thickness of the cylinder body and cubic spline function,respectively,and use the isotonic curve to design the cylinder head curve.Based on the data of the above cylinders,APDL language is used to establish the exact finite element model of the gas cylinder,the fiber layer model with variable thickness and angle of the head section was established by setting the real constant,in the model,by setting the binding contact relation between the aluminum nozzle and the plastic liner,the connection relation between the aluminum nozzle and the plastic liner is simulated.(2)At 70 MPa nominal working load,the maximum equivalent stress value of the aluminum nozzle of the gas cylinder and the plastic liner exceeds the yield strength of the material,therefore,it is necessary to optimize the structure of aluminum nozzle and plastic liner.The stress analysis of the parts with high local stress in the model found that,under internal pressure,the aluminum nozzle of the gas cylinder will produce a specific axial movement,the externally wound fiber layer prevents it from moving axially and thus squeezes it causing excessive local stress.By thickening the plastic liner where the local stress is too high,and rounding of the corners of the mouth of the aluminum bottle and the base,the maximum equivalent stress of the aluminum nozzle is reduced to 157.036 MPa.(3)At 70 MPa nominal working load,the stress distribution in the fiber layer of the cylinder head section is complicated.The stress value of the circumferential layer is twice that of the spiral layer,under the influence of head structure,fiber layer thickness,and other factors,the stress of the fiber layer at the transition between the head and barrel body is higher.In the circumferential layer,due to the thickness difference between the last and first circumferential layers,therefore,the equivalent stress value of the last annular layer is lower than that of the first annular layer.The maximum equivalent stress of the fiber layer does not exceed the longitudinal tensile strength of the fiber.(4)Due to the uneven distribution of fiber layer thickness in the head section,the local stress of the fiber layer in the head section is too high,in this paper,the secondary reaming and winding of gas cylinders are simulated.After reaming and winding,at a nominal working load of 70 MPa,the equivalent stress of the first and last circumferential layers of the cylinder decreases,however,as the radius of the pole hole increases,the winding angle increases,therefore,the equivalent stress value of the reaming and winding spiral layer is higher.In designing the burst pressure,the equivalent stress of the first spiral layer and the first circumferential layer is improved.(5)Given the low liner stiffness of the plastic liner fiber winding hydrogen storage bottle,eigenvalue buckling analysis was performed on the gas cylinder liner,combined with the critical buckling load obtained by eigenvalue buckling analysis,the tension of the fiber during winding is calculated,this value can provide a reference for fiber winding tension design in the actual production process.