Analysis and Design Of Composite Pressure Vessel under Fatigue Loading

Abstract

Composite materials are finding increased use in structural application, due to many advantages such as low weight but high strength and stiffness, corrosion resistance. For efficient designing of composite pressure vessel, American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section X, is introduced. In this report design of the composite pressure vessel subjected to internal pressure is carried out. For calculation of stresses and strains in structure lamination and shell theory is used. Lamination theory is used for calculation of stresses and strain in each layer of composite pressure vessel and shell theory is used for calculation of curvature effect. On the basis of two theories software of composite pressure vessel is developed. Once the stresses and strains in each layer are known then by application of strength ratio sequence of failure of layer can be determined. Parametric studies of variation of laminate configuration and thickness is done with the help of software. Results calculated by software are compared with the experimental data available in literature. Also life of composite pressure vessel is calculated by using composite fatigue software. S-N curve at known frequency and stress ratio is given as input to software. Optimization methodology for filament winding layer is studied. Due to optimization of winding angle there will considerable reduction weight of structure occurs. Analysis of type 1 and type 2 CNG cylinders is done. In type 1 CNG cylinder is of metal and in type 2 fibre reinforced CNG cylinder is consider. In type 2 CNG cylinder there will be considerable amount of weight reduction occur due to use of composite material.