Internal Liner Stability Analysis And Burst Pressure Study Of Composite Pressure Vessel

The composite material is widely used in the aerospace industry, automotive industry, mechanical industry and chemical engineering industry because of its high specific strength and specific stiffness, good designability and simple manufacturing process. The weight and production costs of the vessel can be reduced a lot, at the same time, we can ensure that the vessel has sufficient strength if we adopt composite pressure vessel. The composite material is anisotropic, so it’s difficult to do the mechanics analysis for filament-wound cylinder pressure vessel. The researches on the filament-wound cylinder pressure vessel are focused on strength analysis, progressive failure and so on. However, the study of internal liner stability is much less. Burst pressure is an important parameter for the composite pressure vessel. With it, we can use the vessels safely. For the reasons above, we carried out researches of the internal liner stability and predict the burst pressure of composite pressure vessel. There are three parts in my research.The first part is the mechanics analysis of the composite pressure vessel. I started from the stress-strain relations of a ply. Then I studied the mechanical constitutive relations of a single laminate plate which is consisted of the wall thickness of composite pressure vessel. Finally, the mechanical constitutive relations of all the laminates along the wall thickness direction are studied. After that, the commonly used failure modes and failure criterions are stated. According to the analysis above, some mechanical characters of the composite pressure vessel are concluded.In the second part, mechanical analysis of the composite layer are carried out, using the grid theory and the method of calculating the minimum thickness of composite layer is stated. Then the problem about internal liner stability is studied and the minimum bonding strength calculation formula between internal liner and fiber winding layer is obtained. In order to test the accuracy of the formula, finite element analysis of a composite vessel is done, using ANSYS, and the results match the one obtained by the formula very well, which illustrates that the formula is reasonable.In the third part, the specific process of using ABAQUS to predict the burst pressure of the filament-wound cylinder pressure vessel is discussed. A3-D simulation model is developed according to the composite pressure vessel in my laboratory. The stress distribution of the shell, head, hoop winding layer and spiral winding layer is obtained from the FEA (finite element analysis) simulation results. As a result, we can know the stress characteristics of the vessel clearly. Finally, we predicted the burst pressure of a composite vessel, using maximum strain criterion and carried out the blasting experiment of the vessel, the burst pressure we predicted matches the experimental data well, which means that the process of doing the FEA is right.