Abstract: Large high-pressure vessels are often needed to be used as reaction or storage vessels in petrochemical and aerospace industries. Being restricted by the material thickness and inhomogeneity of mechanical properties in the direction of wall thickness of single-layer cylinder, the structure of multilayered weld-shrunk cylinder; single-layer spherical head with good stress and economic efficiency are generally adopted. According to the pitch diameter formula, the wall thickness of cylinder is approximately twice that of the spherical head. However, due to the structural discontinuity of the joint between the cylinder and the spherical head, there are stress concentration and edge stress. Therefore, the ratio of wall thickness and the connection form are worth discussing. This paper analyzes several types of local connection structures and compares their finite element analysis results. Then it presents the optimization path for the local structure, which provides reference for the design of similar vessels.

Key words: high-pressure vessel, multilayered weld-shrunk cylinder, spherical head, connection structure