Abstract: As the storage and transportation pressure vessel, spherical tank is widely used in chemical engineering, petroleum and other fields. In the process of manufacture and usage, defects such as cracks can easily appear, which will results in safety risks. In this paper, the finite element analysis is carried out on a Q370R steel spherical tank with penetrated crack by adopting ANSYS software, and the defect is evaluated by applying the general failure assessment diagram based on J-integral theory. This method can provide a reference for the safety evaluation of pressure vessels with defects.

Key words: spherical tank, the penetrated crack, defect assessment, J-integral, failure assessment diagram