optimal geometry design and finite element analysis of welded internal stiffener ring in cylindrical vessel made of high strength aluminum

Authors

1 tarbiat modares university

2 amirkabir university of technology

Abstract

Design of structures in aerospace needs minimum weight. Cylindrical thin-walled pressure vessels are one of the most functional among these structures and one of the main ways to reduce weight of these structures is using stiffener rings. In this research in order to find optimum structure weight, internal stiffener ring dimensions were optimized with genetic algorithm coupled with a neural network. In other hand, for joining the stiffener rings to vessel, welding is a conventional way. However, this process can produce welding residual stresses and distortions, which add to external loads and cause structure failure. So in order to predict and control these effects, a comprehensive simulation tool was developed to predict distortions and residual stresses generated in double sided fillet-welded internal stiffener ring on a cylindrical pressure vessel. Results showed that the T-stiffener ring have the best results and the optimum ring dimensions were determined and reported. In addition, magnitude of residual stresses was near to half of base metal yield strength and in weld region, hoop residual stress was tensile and axial residual stress was tensile on inner surface and compressive on the outer surface of vessel. Moreover Effect of tack welds were appeared on residual stress distribution like tiny peaks and have more effect on hoop residual stress distribution on stiffener ring position.

Keywords

Main Subjects

References

[1] Dwight J) 1999 (Aluminum design and construction, Taylor & Francis Group.
[2] Mathers G) 2002 (The welding of aluminum and its alloys. Woodhead Publishing Ltd.
[3] Morrow WM, Schmit LA (1968) Structural synthesis of a stiffened cylinder. NASA CR.
[4] Papadrakakis M, Tsompanakis Y, Lagaros ND (1999) Structural shape optimization using evolution strategies. Eng Opt Jour 31: 515–540.
[5] Sadeghifar M, Bagheri M, Jafari A (2010) Multiobjective optimization of orthogonally stiffened cylindrical shells for minimum weight and maximum axial buckling load. Thi Wal Struct 48: 979–988.
[6] Damodar RA, Navin J (2001) Optimal design of grid stiffened panels and shells with variable curvature. Compos Struct 53: 173–80.
[7] Bagheri M, Jafari AA (2007) Multi objective optimization of orthogonally stiffened cylindrical shells for buckling loads. Int Conf on Multidis Des Opt and App. Besancon, France.
[8] Sattari-Far I, Farahani M (2009) Effect of the weld groove shape and pass number on residual stresses in butt welded pipe. Int Jour Pres Ves and Pip 86: 723–731.
[9] Teng T, Cheng L (1998) Effect of welding conditions on residual stresses due to butt welds. Int Jour of Pres Ves and Pip 75: 857–864.
[10] Brickstad B, Josefson B (1998) A parametric study of residual stresses in multi-pass butt-welded stainless steel pipes. Int Jour of Pres Ves and Pip.75: 11–25.
[11] منهاج م ب (1389) هوش محاسباتی. مرکز نشر دانشگاه صنعتی امیرکبیر.
[12] عطارها م ج (1388) تحلیل المان محدود جوش ذوبی به منظور تعیین یک سیستم مانیتورینگ دما جهت کنترل کیفیت جوش در حین جوشکاری. پایان نامه کارشناسی‌ارشد مهندسی مکانیک. دانشگاه صنعتی امیرکبیر.
[13] Kamala V, Goldak J (1993) Error due to two dimensional approximations in heat transfer analysis of welds. Wel Jour 72(9):440–446.
 
 
[14] Goldak J, Chakravarti A, Bibby M (1984) A new finite element model for welding heat sources. Met Trans 15: 299–305.
[15] Goldak J, Bibby M, Moore J (1986) Computer modeling of heat flow in welds. Met Trans 17(3): 587–600.
[16] Lin M, Eager T (2005) Influence of arc pressure on weld pool geometry. Wel Jour 64(6): 163–169.
[17] Malik AM, Qureshi EM, UllahDar N, Khan I (2008) Analysis of circumferentially arc welded thin-walled cylinders to investigate the residual stress fields. Thi Wal Struct 46: 1391–1401.
Journal of Solid and Fluid Mechanics
Volume 4, Issue 2 - Serial Number 2
May and June 2014
Pages 13-23

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