Preparation And Molding Process Of Type Ⅳ Carbon Fiber Hydrogen Cylinder

Hydrogen storage pressure vessels play a crucial role in the development of onboard hydrogen storage technology for fuel cell vehicles.In comparison with traditional metal pressure vessels,type Ⅳ carbon fiber composite hydrogen tanks exhibit outstanding advantages such as being lightweight,having high strength,and good corrosion resistance.These features effectively reduce the weight burden of the equipment itself,improve its efficiency,and enhance its safety performance.However,composite materials have limited modification effects and are more prone to deformation than metals when subjected to external forces and other loads.Additionally,the anisotropy of fiber-wrapped composite materials can easily cause hydrogen tanks to explode due to deformation caused by external forces.This greatly reduces the stability and reliability of the structure of composite hydrogen tanks.Therefore,in the design process,it is essential to fully consider the structural characteristics of the materials and avoid safety issues caused by design defects.To address the limitations of composite material interface modification and fully exploit the performance advantages of materials,thus achieving a more reliable and stable structural design.This study fully considers the material characteristics of composite materials and the influence of manufacturing methods and process parameters on the performance of type Ⅳ carbon fiber hydrogen tanks during design experiments.Through an in-depth exploration of the winding structure,forming process,and mechanical analysis of type Ⅳ hydrogen tanks,the key technical difficulties in the design and preparation process have been solved,providing theoretical and practical guidance for the design and manufacture of type Ⅳ hydrogen tanks.The specific research contents are as follows:(1)By conducting an NOL(Naval Ordnance Laboratory)ring test to obtain the tensile strength and using the fiber volume content to calculate the equivalent fiber strength,the composite material performance parameters are estimated using the bridging theory.Thin film theory is also utilized for the analysis of the geometric characteristics and stress analysis of type Ⅳ hydrogen tanks.(2)The study investigates the influence of the NOL ring of composite materials on the quality of fiber-wrapped products under different tension parameters(40 N,45 N,and50 N).Using Design Expert software,response surface analysis is performed on process parameters with significant effects on mechanical properties,which are adjustable in the fiber-wrapping process(winding tension,winding speed,and curing temperature).Mathematical models are generated,and the coupling effects of different process parameters on the NOL ring’s mechanical properties are analyzed.A satisfaction function is employed to synthesize the two mechanical performance response variables into a comprehensive indicator for parameter optimization.Finally,experiments are conducted to verify the reliability of the design scheme.(3)Design the structure of a type Ⅳ carbon fiber hydrogen cylinder with a volume of 8 L and a working pressure of 75 MPa.Screen the materials for the liner and metal valve seat;compare the structural characteristics of different heads by deriving the equitension head curve and the elliptical head curve,and calculate the functional relationship between the core mode angle and the cylinder diameter to obtain the optimal winding pattern.Based on stress analysis and mesh theory,calculate the winding angle,the number of layers,thickness,and winding layer number and thickness in the circumferential direction of the cylinder body.Use a cubic spline function to optimize the winding layer of the head and obtain the thickness in the parallel circle band.Finally,verify the rationality of the design scheme using finite element analysis.(4)Based on the principles of composite materials,structural design schemes,and process parameter requirements,the goal is to fabricate a type Ⅳ carbon fiber hydrogen cylinder.Firstly,the fiber winding machine is used to perform winding debugging.Then,carbon fibers,resins,and liners are selected for cylinder fiber winding forming.By properly setting the parameters,the outer diameter dimensions can meet the requirements of winding thickness design.After winding,curing,and finishing,hydraulic burst testing is carried out to validate the design scheme.The present study on the forming process and performance testing of type Ⅳ carbon fiber hydrogen cylinders has yielded favorable results,providing various options for the structural design of type Ⅳ carbon fiber hydrogen cylinders.The coupling analysis of multiple process parameters has further promoted the development of fiber winding structures,establishing a solid foundation for the development and industrial application of lightweight and high-strength carbon fiber hydrogen cylinders.