Effect Of Hoop-wrapped Tension On The Stresses Of The Composite Cylinder Liner

Composite cylinder is consisted of the inner metal liner and the fiber layers.It has been widely employed in astronautics industry,aeronautics industry,civil structures,automotive industry,chemical industry,mechanism industry,construction,energy sources.Because it has lots of merits,such as high stiffness,high-intensity,good corrosion.As the widely application of composite cylinder,scientific and exact stress analysis to composite cylinder is beneficial to cylinder design and machining study and it is crucial on safety assessment of cylinder. Finite element method(FEM) has been already most important method of composite cylinder study,because finite element method(FEM) has been maturely employed in lots of engineering fields and computer power of computer is great improvement.Stresses were analysed to the liner of composite cylinder with ANSYS software and FEM.Structure size, meshing,displacement condition and solution of composite cylinder model are designed by APDLBy taking a composite cylinder which metal inner is 406mm out diameter and 5mm thickness as a study object,the research on hoop-wrapped composite cylinder is developed in this paper,the research results are as follows:(1)Boundary condition,contact condition,material characteristic and element choice are discussed.Calculations were done to the cylinders based on three-dimensional symmetry FEM model.The calculation results show the model was correct.(2)Calculations and stresses analysis were done to the liner of cylinder with layer-by-layer winding.The result shows that the liner has a certain degree of pre-stress which is compressive stress.The liner stresses are linear with equivalent pressure caused by hoop-wrapped tension.The liner stresses increase with the number of carbon fiber layers increasing,but the trend of increasing is low.Increment of the liner stresses reduce with the number of carbon fiber layers increasing.(3)Autofrettage was studied to pre-stress composite cylinder.The result shows autofrettage can reduce stress level of the liner on operating pressure,so autofrettage design can improve load capacity of cylinder.The stresses of the liner and fiber layer on zero pressure increase with autofrettage increasing.The best autofrettage can improve load capacity.The low equivalent pressure caused by tensile force can reduce stress of the liner on operating pressure.The number of fiber layers affect stress lever of the liner and fiber layer. Stresses of the liner are small changes,but stresses of the fiber layer are significant changes.