Static Analysis of Buttress Threads Using the Finite Element Method

1992 ◽  
Vol 114 (2) ◽  
pp. 209-212 ◽  
Author(s):  
A. Chaaban ◽  
M. Jutras

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.

Author(s):  
Benjamin Hantz ◽  
Venkata M. K. Akula ◽  
John Leroux

For pressure vessels, loss of thickness detected during scheduled maintenance utilizing UT scans can be assessed based on Level 1 or 2 analyses as per API 579 guidelines. However, Level 1 and 2 analyses can point to excessively conservative assessments. Level – 3 assessments utilizing the finite element method can be performed for a more accurate estimate of the load carrying capacity of the corroded structure. However, for a high fidelity structural response prediction using the finite element method, the characteristics of the model must be accurately represented. Although the three nonlinearities, namely, the geometric, material, and contact nonlinearities can be adequately included in a finite element analysis, procedures to accurately include the thickness measurements are not readily available. In this paper, a tool to map thicknesses obtained from UT scans onto a shell based finite element models, to perform Level – 3 analyses is discussed. The tool works in conjunction with Abaqus/CAE and is illustrated for two different structures following the elastic-plastic analysis procedure outlined in the API 579 document. The tool is intended only as a means to reduce the modeling time associated with mapping thicknesses. The results of the analyses and insights gained are presented.


2006 ◽  
Vol 129 (3) ◽  
pp. 550-555
Author(s):  
Ping Chen ◽  
Caifu Qian ◽  
Yunxiao Zhang

Because of large scale and heavy weight, end closures of high pressure vessels are usually hard to assemble and disassemble. In this paper, a new quick-opening seal device connected by D-shaped shearing bolts is introduced. This device is compact in structure, reliable in sealing, easy in assembly and disassembly, and very appropriate for end closures of pressure vessels or for pipe joints. Strength calculation formulas for the major parts are proposed analytically, and stress analysis using the finite element method for a C-ring seal has been performed. An application of this device shows that its sealing and strength is reliable.


Author(s):  
I Atanasovska ◽  
R Mitrović ◽  
D Momĉilović ◽  
A Subic

This research investigates the effects of the nominal load value on load distribution of simultaneously meshing gear teeth pairs, and on the involute gear load capacity. The research results presented in this article confirm that the nominal load value has a significant influence on the gear load capacity calculations. However, this influence is generally neglected in standard gear calculations, which can result in oversized gear dimensions. This can lead to inadequate gear designs in practice due to increased demand for reduced gear size and weight in modern machinery. The article provides a detailed description of the iterative numerical method developed in this research to support the modelling and analysis of load distribution in meshed gears using the finite-element method.


1983 ◽  
Vol 22 ◽  
Author(s):  
A. Chaaban ◽  
K. Leung ◽  
R. J. Pick ◽  
D. J. Burns

ABSTRACTThe finite element method has been used to investigate the stress fields in blind end closures of thick-walled pressure vessels. A design curve for choosing end thickness has been developed by elastic analysis of a range of geometries and by elastic-plastic analysis of several geometries. The effects of inner corner radius of the blind end and a small central hole in the end are discussed.


Sign in / Sign up

Export Citation Format

Share Document