| With the rapid development and industrialization of hydrogen fuel cells and electric vehicles,type IV hydrogen storage cylinder has become a global research hotspot due to its lightweight,excellent fatigue performance and other characteristics.At present,carbon fiber is generally used as the main composite material for Type IV hydrogen storage cylinder.However,due to the requirement of light weight,this paper will use aramid fiber with lighter weight as the main composite material,and carry out its structural design,simulation analysis,fatigue analysis and optimal self-tightening force optimization.In this paper,70 MPa IV hydrogen storage cylinder is mainly studied in the following aspects:(1)Design the structure of aramid composite material type IV hydrogen storage cylinder.According to the design index,the overall design of the liner structure was carried out,and the preliminary design of the liner structure and fiber reinforced layer was carried out based on the grid theory.According to the laminated theory,the second failure strength theory and Tcai-Hill strength theory are used to check the strength twice to ensure the requirements of composite strength.(2)Finite element design of aramid composite type IV hydrogen storage cylinder under different internal pressure conditions.Finite element model is established based on ABAQUS and WCM plug-in.For the buckling analysis of the plastic liner,in order to prevent the plastic liner from buckling during the fiber winding process,the liner should be filled with about0.1MPa hydrogen pressure during the winding process.Through the stress and strain analysis of the cylinder under each load condition,to ensure that the cylinder can meet the design requirements of the cylinder under each load condition.(3)Fatigue optimization design of gas cylinders.ABAQUS was used to analyze the stress of gas cylinders under different self-tightening pressures,and the influences of different selftightening pressures on the average stress and fiber stress ratio of gas cylinders were obtained.It can be seen that the fatigue resistance of the cylinder is improved by reducing the average stress of the cylinder.The optimum self-tightening force is obtained according to the constraint condition of fiber stress ratio.The fatigue life of cylinders is increased by 200% after selftightening treatment,which can prove that the fatigue life of cylinders can be greatly improved by self-tightening treatment.To sum up,this paper takes aramid composite material type IV hydrogen storage cylinder as the research object,selects aramid fiber composite material as the winding layer material,carries on the overall structure design,and adopts the finite element software ABAQUS to study the strength of low temperature and high pressure hydrogen storage cylinder and the fatigue life of composite gas cylinder,and obtains the optimal self-tightening pressure and fatigue cycle number.It provides a theoretical basis for reducing the cost of low temperature and high pressure hydrogen storage and improving the number of safe cycles. |
