Static Analysis of Buttress Threads Using the Finite Element Method

The finite element method has been used to investigate the stress field in threaded end closures of thick-walled high pressure vessels. A set of elastic analyses of vessels with 5, 8, 11, 15, 20 and 25 standard Buttress threads was used to propose a method for predicting the load distribution along the length of the thread. Root stress index factors in the region of the first three active threads are also included. The results of the present work contribute to the development of the new division of the ASME Pressure Vessel Code which is related to thick-walled high pressure vessels.