ORIGINAL PAPER
Application of Two Conditions of Loss of Stability in Analysis of the Tube Bending Process
 
 
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Opole University of Technology, Faculty of Managing the Power Industry, 45-036, Opole, ul. Luboszycka 7, Poland
 
 
Online publication date: 2019-12-04
 
 
Publication date: 2019-12-01
 
 
International Journal of Applied Mechanics and Engineering 2019;24(4):200-223
 
KEYWORDS
ABSTRACT
In this paper, the derivation of expressions for admissible values of strains and stresses for vertex points of layers subjected to tension during tube bending at bending machines is presented. The conditions of the dispersed and located loss of stability of the bent tube were assumed as criteria of instability. The original element of this paper is the extension of the criterion of strain location in a form of possible initiation of a neck or furrow (introduced by Marciniak for thin plates [1]) to bending thin- and thick-walled metal tubes at bending machines. The conditions of the dispersed and localized loss of stability together with formation of the plane state of deformation (PSD) in the plane stress state (PSS) were assumed as the criteria of instability. The calculation results were presented as graphs being useful nomograms. We present also simple examples of calculations of permissible and critical strains and values of bending angles including and not including displacement of the neutral axis y0, during cold bending metal thin-walled tubes at bending machines for bending angles <0o; 180o>.
 
REFERENCES (45)
1.
Maciniak Z. (1971): Limit Deformations in Sheet Metal Stamping [in Polish]. – Warsaw: WNT.
 
2.
Śloderbach Z. (1999): A model of deformation geometry in pipe bending processes. – Engineering Transactions, vol.47, No.1, Warsaw, pp.3-20.
 
3.
Śloderbach Z. and Strauchold Sz. (1999): Approximate methods for evaluating strains in pipe bending processes [in Polish]. – Technical Inspection, No 1/99, Warsaw, pp.1-6.
 
4.
Beskin L. (1945): Bending of thin curved tubes. – Journal of Applied Mechanics, Transactions of the ASME, vol.12.
 
5.
Boyle M. (1971): Bending thin wall stainless tubing. – Machinery, No77/71, London.
 
6.
Dzidowski E.S. (2001): Reliability and solving problems in thin-walled pipe bending processes for the case of great manufacturing tolerance [in Polish]. – Fourth Conference PIRE 2001, ISBN 83-909539-3-5, Lądek Zdrój, pp.91-101.
 
7.
Dzidowski E.S. and Strauchold Sz. (1998): Effect of technological factors in pipe bending on damage characteristics and reliability of power pipelines [in Polish]. – Scientific Books of the Opole University of Technology, Series Electricity, vol.6, Opole, pp.119-125.
 
8.
Franz W.D. (1961): Das Kalt-Biegen von Rohren. – Berlin: Springer-Verlag.
 
9.
Gruner P. (1960): Über rohrbiegeverfahren. – Maschinenmarkt, vol.30/31, pp.120-129.
 
10.
Grunow O. (1985): Praktisches Rohrbiegen. – Berlin: Springer-Verlag.
 
11.
Korzemski J.W. (1968): Thin-walled pipe bending with use of the mandrels [in Polish]. – Mechanic, 4/68, Warsaw, pp.207-210.
 
12.
Korzemski J.W. (1963): Thin-Walled Pipe Bending [in Polish]. – Warsaw: WNT.
 
13.
Pesak F. (1963): Bending thin wall tubing. – Machinery, vol.60, pp.147-151.
 
14.
Śloderbach Z. and Rechul Z. (2000): Effect of strain hardening and normal anisotropy on allowable values of strain and stress in pipe-bending processes. – Journal of Theoretical and Applied Mechanics, vol.38, No.4, Warsaw, pp.843-859.
 
15.
Śloderbach Z. and Pajak J. (2015): Determination of the thicknesses of pipe elbows on the basis of expressions resulting from EU-Directive. – Archive of Applied Mechanics, vol.85, No.5, pp.629-640.
 
16.
Śloderbach Z. (2002): Some problems of mechanics in pipeline bending processes [in Polish]. – Publishing House of the Wrocław University of Technology, ISBN 83-7085-665-9, Wrocław.
 
17.
Śloderbach Z. (2010): The conditions of instabilitiy in the plastic deformations analysis [in Polish]. – Publishing House of the Opole University of Technology ISBN 978-83-60691-85-4, Opole.
 
18.
Śloderbach Z. (2014): A derivation of the generalized model of strains during bending of metal tubes at bending machines. – International Journal of Applied Mechanics and Engineering, vol.19, No.1, University of Zielona Góra, pp.145-163.
 
19.
Tang N.C. (2000): Plastic-deformation analysis in tube bending, International Journal of Pressure Vessels and Piping. – Publisher Elsevier UK, vol.77, No.12, pp.751-759.
 
20.
UDT CONDITIONS (WUDT-UC-WO-O/02:10). (2003): Pressure Installations. General Requirements. Bending Elbows. Strength Calculations [in Polish]. – No.1, Warsaw.
 
21.
Wick CH., Benedict J.T. and Veilleux R.F. (2001): Tool and manufacturing engineers handbook. A reference book for manufacturing engineers, managers and technicans. Volume II, Forming, Fourth Edition. – Society of Manufacturing Engineers, One ASME Drive, Dearbon, Michigan, USA.
 
22.
Zhang Z., Yang H., Li H., Ren N. and Tian Y. (2011): Bending behaviors of large diameter thinwalled CP-Ti tube in rotary draw bending – Progress in Natural Science: Materials International, vol.21, pp.401-412.
 
23.
Zhiqiang J., Mei Z., He Y., Xudong X. and Guangjun L. (2011): Deformation behavior of medium strength TA18 high-pressure tubes during nc bending with different bending radii. – Chinese Journal of Aeronautics, vol.24, pp.657-664.
 
24.
Zdankiewicz M. (1970): Investigations of the cold tubes bending processes [in Polish]. – Mechanic, No 7/70, Warsaw, pp.609-519.
 
25.
Zdankiewicz M. (1998): European directive concern a pressure installations. design recommendations for pressure vessels – manufacturing [in Polish]. – Dozór Techniczny, No 2/98, Warsaw, 25-33 and 48.
 
26.
Dobosiewicz J. and Wojczyk K. (1998): Life prediction for steam pipeline bends [in Polish]. – Energetics, nr 3/88, Katowice, pp.88-90.
 
27.
Śloderbach Z. and Pająk J. (2013): Stored energy of plastic deformations in tube bending processes [in Polish]. – International Journal of Applied Mechanics and Engineering, vol.18, No.1, pp.235-248.
 
28.
Śloderbach Z. (2015): Derivation of relations and analysis of tube bending processes using discontinous fields of plastic strains. Part I. Derivations of geometric-analytic relationships. Part II. Discussion and analysis of the obtained results. – International Journal of Applied Mechanics and Engineering, vol.20, No.2, pp.417-435.
 
29.
Śloderbach Z. (2017): Application of the continuous and discontinuous fields of plastic deformations to the evaluations of the initial thickness of bent tubes. – Journal of Engineering Materials and Technology, vol.139, No.1, pp.011009-1 011009-10.
 
30.
Życzkowski M. and Skrzypek J. (1971): Influence of bending, torsion and tension on the stationary creep of a pipe line, archives of mechanics. – Vol.23, No.4, pp.465-494.
 
31.
EN 13445-4. (2009): „ Unfired Pressure Vessels” – Part 4: Fabrication, (point 9.2.4 Tube Bents, expression 9.2-4), or earlier: Draft Standart EN UFPV. (May 1996)”Unfired Pressure Vessels” – Part 4. “Manufacture”, CEN/TC54/267 JWGB N277, rev.5.
 
32.
El-Sebaie M.G. And Mellor P.B. (1972): Plastic Instability Conditions In The Deep-Drawing Of A Circular Blank Of Sheet Metal. – International Journal Of Mechanical Science, Vol.14, Pp.535-556.
 
33.
Gabryszewski Z. and Gronostajski J. (1991): Fundamentals of Metal-Working Processes [in Polish]. – Warsaw: PWN.
 
34.
Hill R. (1985): Mathematical Theory of Plasticity. – London: Oxford, Clarendon Press.
 
35.
Moore G.G. and Wallace J.F. (!964/1965): The effect of anisotropy on instability in sheet-metal forming [in Polish]. – Journal of the Institute of Metals, vol.93, No.2, pp.33-38.
 
36.
Śloderbach Z. (2015): Conditions Of Stability Loss During The Test Of Hydraulic Forming Of Drawpieces. Part I. Derivation Of Basic Equations And Relationship. Part II. Discussion And Analysis Of The Obtained Results. – International Journal Of Applied Mechanics And Engineering, Vol.20, No.4, Pp.917-938.
 
37.
Erbel S., Kuczyński K. and Marciniak Z. (1986): Plastic Metal-Working Processes [in Polish]. – Warsaw: PWN.
 
38.
Marciniak Z. and Kołodziejski J. (1983): Fundamentals of Metal-Working Processes [in Polish]. – Warsaw: Warsaw University of Technology.
 
39.
Olszak W., Perzyna P. and Sawczuk A. (1985): Theory of Plasticity [in Polish]. – Warsaw: PWN.
 
40.
Swift H.W. (1962): Plastic instability under plane stress. – Journal of the Mechanics and Physics of Solids, vol.1, No.1, pp.1-76.
 
41.
Szczepiński W. (1993): Theory of Plastic Working of Metals [in Polish]. – Warsaw: PWN.
 
42.
Raniecki B. and Sawczuk A. (1975): Thermal effects in plasticity. Part I. Coupled theory. – Zeitschrift fur Angewandte Mathematik und Mechanik, ZAMM, vol.55, pp.333-341.
 
43.
Raniecki B. and Sawczuk A. (1975): Thermal effects in plasticity. Part II. Uniqueness and aplications. – Zeitschrift fur Angewandte Mathematik und Mechanik, ZAMM, vol.55, pp.363-371.
 
44.
Marciniak Z. (editor). (1987): Plastic Metal-Working Processes. Which Methods of Forming? On Cold, Hot or Half-Hot? [in Polish]. – Mechanics, SIMP, No2, Warsaw.
 
45.
Nowacki W.K. (1985): Thermal Effects In Dynamic Plasticity, Numerical Solution And Experimental Investigations (Thermographic-Infrared Detection). – Journal De Physique, Vol.48, No.8, pp.113-119.
 
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