Abstract




 
   

IJE TRANSACTIONS C: Aspects Vol. 30, No. 9 (September 2017) 1309-1318   

PDF URL: http://www.ije.ir/Vol30/No9/C/3.pdf  
downloaded Downloaded: 33   viewed Viewed: 245

  FIELD STUDY AND EVALUATION OF BUCKLING BEHAVIOR OF CYLINDRICAL STEEL TANKS WITH GEOMETRIC IMPERFECTIONS UNDER UNIFORM EXTERNAL PRESSURE
 
M. Rastgar and H. Showkati
 
( Received: February 24, 2017 – Accepted in Revised Form: July 07, 2017 )
 
 

Abstract    Construction and assembling process of shell structures has caused main problems. In these structures, there is no possibility for the integrated construction due to their large shell extent and they are built using a number of welded curved panel parts; hence, some geometrical imperfections emerge. Most of these imperfections are caused by the process of welding, transportation, inappropriate rolling, as well as installation and implementation problems. In this research, construction of steel cylindrical tanks in one of the refinery site is monitored using a field survey and created imperfections are identified and introduced. Relying on the statistical inference, they are classified and then, by studying the effective factors and origin in their generation, the common imperfections are identified. The impact of common imperfections on the buckling behavior is experimentally evaluated under uniform external pressure. Then, nonlinear analysis of the test specimens are performed by ANSYS software. Finally experimental results, finite element and analytical relations are compared. The obtained results show that the imperfections have a direct impact on the structural behavior of shells during the buckling under uniform external pressure load. Also, some imperfections caused by welding increase the buckling resistance of cylindrical shells.

 

Keywords    field study, buckling behavior, external pressure, cylindrical tank, geometric imperfection.

 

چکیده    در اجرای سازه هاي پوسته ای جدار نازک، به علت وسعت زياد پوسته، امکان ساخت يکپارچه وجود نداشته و از تعدادی قطعات پانلي دارای انحنا که به يکديگر جوش داده شده اند ساخته مي شوند به همين دليل يک سری نقص های هندسي يا به عبارت بهتر ناکاملي های هندسي بروز مي کند. عمده اين ناکاملي ها در اثر فرآيند جوشکاري، حمل و نقل، رولينگ نامناسب و مشکلات نصب و اجرا بوجود مي آيند. در اين تحقيق، اجرای مخازن استوانه اي فولادي در يکي از سايت های پالايشگاهي، به صورت ميداني تحت نظارت قرار گرفته و ناکاملي های ايجاد شده شناسایی و معرفي مي شوند. با برداشت آماري و اندازه گيري اين ناکاملي ها، گروه بندي آنها انجام گرفته و با بررسی منشا و عوامل موثر در پيدايش آنها، ناکاملي های رايج مشخص مي گردد. در ادامه تاثير ناکاملي ها بر رفتار کمانشی بصورت آزمايشگاهي تحت اثر فشار خارجي يکنواخت بر روی نمونه های آزمايشگاهي با مقياس مشخص مورد ارزيابي قرار مي گيرد. همچنين آناليز المان محدود غيرخطي اين نمونه هاي آزمايشگاهي توسط نرم افزار المان محدود ANSYS انجام شده و نتايج آزمايشگاهي، المان محدود و روابط تحليلي مقايسه مي شوند. نتايج به دست آمده نشان مي دهند که ناکاملي ها تاثير مستقيمي بر رفتار سازه اي پوسته ها هنگام کمانش تحت بار فشار خارجي یکنواخت دارند. همچنین بعضی از ناکاملی های ناشی از جوشکاری باعث افزایش مقاومت کمانشی پوسته های استوانه ای می شوند.

References   

1.      Shen, H.-s. and Chen, T.-y., "Buckling and postbuckling behaviour of cylindrical shells under combined external pressure and axial compression", Thin-walled Structures,  Vol. 12, No. 4, (1991), 321-334.

2.      Showkati, H. and Ansourian, P., "Influence of primary boundary conditions on the buckling of shallow cylindrical shells", Journal of Constructional Steel Research,  Vol. 36, No. 1, (1996), 53-75.

3.      Golzan, B. and Showkati, H., "Buckling of thin-walled conical shells under uniform external pressure", Thin-walled Structures,  Vol. 46, No. 5, (2008), 516-529.

4.      Wang, J. and Koizumi, A., "Buckling of cylindrical shells with longitudinal joints under external pressure", Thin-walled Structures,  Vol. 48, No. 12, (2010), 897-904.

5.      Chen, L., Rotter, J.M. and Doerich, C., "Buckling of cylindrical shells with stepwise variable wall thickness under uniform external pressure", Engineering Structures,  Vol. 33, No. 12, (2011), 3570-3578.

6.      Aghajari, S., Showkati, H. and Abedi, K., "Experimental investigation on the buckling of thin cylindrical shells with two-stepwise variable thickness under external pressure", Structural Engineering and Mechanics,  Vol. 39, No. 6, (2011), 849-860.

7.      Mohammadimehr, M., Saidi, A., Ghorbanpour Arani, A. and Han, Q., "Postbuckling equilibrium path of a long thin-walled cylindrical shell (single-walled carbon nanotube) under axial compression using energy method", International Journal of Engineering,  Vol. 24, No. 1, (2011), 79-86.

8.      De Paor, C., Kelliher, D., Cronin, K., Wright, W. and McSweeney, S., "Prediction of vacuum-induced buckling pressures of thin-walled cylinders", Thin-walled structures,  Vol. 55, (2012), 1-10.

9.      Alashti, R.A., Rostami, S.L. and Rahimi, G., "Buckling analysis of composite lattice cylindrical shells with ribs defects", International Journal of Engineering-Transactions A: Basics,  Vol. 26, No. 4, (2012), 411-420.

10.    Ghazijahani, T.G., Jiao, H. and Holloway, D., "Longitudinally stiffened corrugated cylindrical shells under uniform external pressure", Journal of Constructional Steel Research,  Vol. 110, (2015), 191-199.

11.    Kalantari, Z. and Razzaghi, M., "Predicting the buckling capacity of steel cylindrical shells with rectangular stringers under axial loading by using artificial neural networks", International Journal of Engineering-Transactions B: Applications,  Vol. 28, No. 8, (2015), 1154-1163.

12.    Fatemi, S.M., Showkati, H. and Maali, M., "Experiments on imperfect cylindrical shells under uniform external pressure", Thin-walled Structures,  Vol. 65, (2013), 14-25.

13.    Abramovich, H., Singer, J. and Weller, T., "Repeated buckling and its influence on the geometrical imperfections of stiffened cylindrical shells under combined loading", International Journal of Non-linear Mechanics,  Vol. 37, No. 4, (2002), 577-588.

14.    Hornung, U. and Saal, H., "Buckling loads of tank shells with imperfections", International Journal of Non-linear Mechanics,  Vol. 37, No. 4, (2002), 605-621.

15.    Khamlichi, A., Bezzazi, M. and Limam, A., "Buckling of elastic cylindrical shells considering the effect of localized axisymmetric imperfections", Thin-walled Structures,  Vol. 42, No. 7, (2004), 1035-1047.

16.    Frano, R.L. and Forasassi, G., "Experimental evidence of imperfection influence on the buckling of thin cylindrical shell under uniform external pressure", Nuclear Engineering and Design,  Vol. 239, No. 2, (2009), 193-200.

17.    Yang, L., Chen, Z., Chen, F., Guo, W. and Cao, G., "Buckling of cylindrical shells with general axisymmetric thickness imperfections under external pressure", European Journal of Mechanics-A/Solids,  Vol. 38, (2013), 90-99.

18.    El-Sawy, K.M., "Inelastic stability of liners of cylindrical conduits with local imperfection under external pressure", Tunnelling and Underground Space Technology,  Vol. 33, No., (2013), 98-110.

19.    Ghazijahani, T.G., Jiao, H. and Holloway, D., "Experiments on dented cylindrical shells under peripheral pressure", Thin-walled Structures,  Vol. 84, No., (2014), 50-58.

20.    Maali, M., Showkati, H. and Fatemi, S.M., "Investigation of the buckling behavior of conical shells under weld-induced imperfections", Thin-walled Structures,  Vol. 57, No., (2012), 13-24.

21.    Vinson, J.R., "The behavior of thin walled structures: Beams, plates, and shells, Springer Science & Business Media,  Vol. 8,  (2012).

22.    Teng, J., Lin, X., Rotter, J.M. and Ding, X., "Analysis of geometric imperfections in full-scale welded steel silos", Engineering Structures,  Vol. 27, No. 6, (2005), 938-950.

23.    Hübner, A., Teng, J. and Saal, H., "Buckling behaviour of large steel cylinders with patterned welds", International Journal of Pressure Vessels and Piping,  Vol. 83, No. 1, (2006), 13-26.

24.             Brush, D.O., Almroth, B.O. and Hutchinson, J., "Buckling of bars, plates, and shells", Journal of Applied Mechanics,  Vol. 42, (1975), 911-920.


Download PDF 



International Journal of Engineering
E-mail: office@ije.ir
Web Site: http://www.ije.ir