تحلیل ناپایداری سازه درام دوار یک موتور توربینی تحت بارهای فشاری و حرارتی

نوع مقاله : علمی پژوهشی

نویسندگان

1 استادیار، مجتمع دانشگاهی مکانیک، دانشگاه صنعتی مالک اشتر

2 کارشناس ارشد، مجتمع دانشگاهی مکانیک، دانشگاه صنعتی مالک اشتر

چکیده

کمانش یکی از دلایل اصلی خرابی در سازه‌های جداره نازک است، بنابراین امکان وجود کمانش را همیشه باید در طراحی و تحلیل آنها در نظر داشت. در این تحقیق یک درام دوار در یک موتور توربینی که چندین ردیف پره روی محیط خارجی آن متصل هستند مورد تحلیل ناپایداری قرار می­گیرد. سازه درام دوار در واقع یک سازه مخروطی جداره نازک است که تحت انواع بارهای مکانیکی و حرارتی قرار دارد. ابتدا درام دوار به صورت یک سازه استوانه ای مدل و در نرم‌افزار المان محدود آباکوس تحلیل و به کمک روابط تئوری مورد صحت‌سنجی قرار می‌گیرد. در ادامه هندسه درام به شکل مخروطی مدل می‌شود و روند تحلیل مشابه حالت قبل انجام می‌گردد. تنش‌های اعمالی روی سازه معین می‌شوند و ضرایب کمانش یا همان مقادیر ویژه استخراج می‌گردند و پایداری سازه درام و عوامل موثر بر آن مورد بحث و بررسی قرار می‌گیرد. نتایج تحلیل نشان می‌دهند میزان تاثیر بارگذاری حرارتی بر کمانش سازه درام بیشتر از بارگذاری‌های فشار خارجی است. در درام مخروطی تنش بحرانی 710 مگاپاسکال و ماکزیمم تنش کاری برابر 660 مگاپاسکال است.

کلیدواژه‌ها

موضوعات


[1] Ahmadi, M., Thermomechanical buckling analysis of composite cylindrical structures in linear elastic media by finite ring method, Master Thesis, Shiraz University of Technology, (1391). (In Persion).
 
[2] Timoshenko, S. P., Gere, J. M., Theory of Stability, 2nd ed., New York, McGraw-Hill, (1961).
 
[3] Seide, P., Axisymmetric buckling of circular cones under axial compression, Journal of Applied Mechanics, Vol. 23, No. 4, pp. 625-628, (1956).
 
[4] Seide, P., Buckling of circular cones under axial compression, Journal of Applied Mechanics, Vol. 28, No. 2, pp. 458-460, (1961).
 
[5] Singer, J., Buckling of circular conical shells under axisymmetrical external pressure, Journal of Mechanical Engineering Science, Vol. 3, No. 4, pp. 330-9, (1961).
 
[6] Weingarten, V., Morgan, E. J., Seide, P., Elastic stability of thin-walled cylindrical and conical shells under combined external pressure and axial compression, AIAA Journal, Vol. 3, No. 3, 500-505., (1965).
 
[7] Burns, A. B., Minimum-weight, hydrostatically compressed, ring-stiffened cones, Journal of Spacecraft and Rockets, Vol. 3, No. 3, pp. 387-392, (1966).
 
[8] Kornecki, A., Buckling of truncated conical shells under uniform static pressure, AIAA Journal, Vol. 5, No.11, pp. 2099-2101, (1967).
 
[9] Berkovits, A., Singer, J., Weller, T., Buckling of unstiffened conical shells under combined loading, Experimental Mechanics, Vol. 7, No. 11, pp. 458-467, (1967).
 
[10] Tani, J., Yamaki, N., Buckling of truncated conical shells under axial compression, AIAA Journal, Vol. 8, No. 3. pp.568-571, (1970).
 
[11] Tani, J., Influence of axisymmetric initial deflections on the thermal buckling of truncated conical shells, Nuclear Engineering and Design, Vol. 48, No. (2-3), pp. 393-403, (1978).
 
[12] Chang, C. H., Katz, L., Buckling of axially compressed conical shells, Journal of The Engineering Mechanics Division, 106, No.3, pp. 501-516, (1980).
 
[13] Tani, J., Buckling of truncated conical shells under combined axial load, pressure, and heating, Journal of Applied Mechanics, Vol. 52, No. 2, pp. 402-408, (1985).
 
[14] Tong, L., Buckling load of composite conical shells under axial compression, Journal of Applied Mechanics, Vol.61, pp. 718-719, (1994).
 
[15] Ross, C. T., Vibration and elastic instability of thin-walled conical shells under external pressure, Computers & structures, Vol. 55, No.1, pp. 85-94, (1995).
 
[16] Pariatmono, N., Chryssanthopoulos, M. K., Asymmetric elastic buckling of axially compressed conical shells with various end conditions, AIAA journal, Vol. 33, No.11, pp. 2218-2227, (1995).
 
[17] Spagnoli, A., Chryssanthopoulos, M. K., Elastic buckling and postbuckling behaviour of widely-stiffened conical shells under axial compression, Engineering structures, Vol. 21, No.9, pp. 845-55, (1999).
 
[18] Spagnoli, A., Different buckling modes in axially stiffened conical shells, Engineering Structures, Vol. 23, No. 8, pp.957-965, (2001).
 
[19] Ross, C. T., Sawkins, D., Johns, T., Inelastic buckling of thick-walled circular conical shells under external hydrostatic pressure, Ocean engineering, Vol. 26, No. 12, pp. 1297-1310, (1999).
 
[20] Chryssanthopoulos, M. K., Poggi, C., Collapse strength of unstiffened conical shells under axial compression, Journal of constructional steel research, Vol. 57, No. 2, pp. 165-184, (2001).
 
[21] Shakoori, M., Investigation of buckling and free vibrations of conical shells connected by analytical method, PhD Thesis, Sharif University of Technology, Summer, (2014). (In Persion)
 
[22] Goldfeld, Y., Arbocz, J., Buckling of laminated conical shells given the variations of the stiffness coefficients, AIAA journal, Vol. 42, No. 3, pp. 642-649, (2004).
 
[23] Patel, B. P., Shukla, K. K., Nath, Y., Thermal postbuckling analysis of laminated cross-ply truncated circular conical shells, Composite Structures, Vol. 71, No. 1, pp. 101-114, (2005).
 
[24] Patel, B. P., Nath, Y., Shukla, K. K., Nonlinear thermo-elastic buckling characteristics of cross-ply laminated joined conical-cylindrical shells, International Journal of Solids and Structures, Vol. 43, No. 16, pp. 4810-29, (2006).
 
[25] Patel, B. P., Singh, S., Nath, Y., Postbuckling characteristics of angle-ply laminated truncated circular conical shells, Communications in Nonlinear Science and Numerical Simulation, Vol. 13, No. 7, pp. 1411-1430, (2008).
 
[26] Błachut, J., Ifayefunmi, O., Buckling of unstiffened steel cones subjected to axial compression and external pressure, Journal of offshore mechanics and Arctic engineering,134, No. 3, pp.1-9, (2012).
 
[27] Shadmehri, F., Hoa, S. V., Hojjati, M., Buckling of conical composite shells, Composite Structures, Vol. 94, No. 2, pp. 787-792, (2012).
 
[28] Castro, S. G., Mittelstedt, C., Monteiro, F. A., Arbelo, M. A., Ziegmann, G., Degenhardt, R., Linear buckling predictions of unstiffened laminated composite cylinders and cones under various loading and boundary conditions using semi-analytical models, Composite Structures, Vol.118, pp. 303-315, (2014).
 
[29] Ghazijahani, T. G., Zirakian, T., Determination of buckling loads of conical shells using extrapolation techniques, Thin-Walled Structures, Vol. 74, pp. 292-299, (2014).
 
[30] Taraghi, P., Showkati, H,. Investigation of the buckling behavior of thin-walled conical steel shells subjected to a uniform external pressure, Iranian Journal of Science and Technology, Transactions of Civil Engineering, Vol. 43, No. 4, pp. 635-48, (2019).
 
[31] Rezaiee-Pajand, M., Masoodi, A. R., Shell instability analysis by using mixed interpolation, Brazilian Society of Mechanical Sciences and Engineering, Vol. 41, No. 10, pp. 1-18, (2019).
 
[32] Bohlooly M., Kouchakzadeh M.A., Mirzavand B., Noghabi M., Dynamic instability characteristics of advanced grid stiffened conical shell with laminated composite skins, Journal of Sound and Vibration, pp. 488- 115572, (2020).
 
[33] Fu T., Wu X., Xiao Z., Chen Z., Dynamic instability analysis of FG-CNTRC laminated conical shells surrounded by elastic foundations within FSDT, European Journal of Mechanics, pp. 85- 104139, (2021).
 
[34] Brush, D. O., Almroth, B. O., Hutchinson, J. W., Buckling of bars, plates, and shells, ASME, (1975).
 
[35] Thornton, E. A., Thermal buckling of plates and shells, Aerospace and Nuclear Engineering.; Vol. 46, No. 10, pp. 485-506, (1993).