Prestressing Estimation for Multilayer Clamping High Pressure Vessel Laminates

Abstract

The stresses on multilayer high pressure vessels during service have been extensively studied. However, there is still a lack of detailed and reliable theoretical analyses of a series of hidden problems in manufacturing, such as the prestressing of laminates during the manufacturing process and, where relevant, the initial inner cylinder thickness. In order to solve the problem of prestressing estimation for laminates, in this study, based on the assumption of uniform contact pressure, the equations for the interlaminar contact pressure as well as the residual circumferential stress expressed in terms of the initial circumferential stress of the laminate are derived and verified by finite element analysis (FEA). In the 16-layer model, the maximum positive deviation was +1.47%, and the maximum negative deviation was −0.08%. Theoretical equations show that each laminate layer can produce a larger residual compressive stress on the inner cylinder at a smaller circumferential stress, thus improving the fatigue performance of the multilayer vessels. As the number of layers increases, the inner cylinder may first experience external pressure destabilization, and thus the contact pressure P1 at the outer wall surface of the inner cylinder needs to be controlled to remain below the critical pressure Pcr of the inner cylinder.