APPLICATION OF THE FINITE-ELEMENT METHOD TO THE QUASI-STATIC THERMOELASTIC ANALYSIS OF PRESTRESS IN MULTILAYER PRESSURE-VESSELS

Multilayered wrapped vessel technology utilizes the compressive prestress induced during construction process to gain a considerable advantage over the monoblock vessels. The compressive prestress allows for more efficient use of construction material and more uniform distribution of stress throughout the vessel's cross section. Analysis of the magnitude of prestress throughout the vessel's thickness has been previously reported (Rasty, 1988). However, one major idealization in such analysis has been the assumption that the magnitude of induced prestress is constant around the circumference of the vessel. In this research, thermoelastic finite element method was utilized to simulate the construction process of one layer of the vessel. It was concluded that the compressive residual stress induced by the weld shrinkage varies through the circumference of the vessel by as much as 13.5 percent. Circumferential distributions of the prestress are presented and compared to the closed-form solutions (constant prestress assumption) in earlier works.