Damping in Space Structure with the MERO Jointing System with Respect to the Degree of Tightness of Bolts

Document Type : Research Article


1 Associate Professor, Department of Civil Eng., Babol Noshirvani University of Technology

2 Professor, Department of Civil Eng., Babol Noshirvani University of Technology

3 M.Sc. in Civil Eng., Department of Civil Eng., Babol Noshirvani University of Technology


One of the most common connecting systems that is used for the manufacture of space structure, is MERO connecting system. So a perfect knowledge of the behavior of this connection is the most essential problem for the engineers and designers. The results has shown that different parameters including the degree of tightness of the bolts affect on the static and dynamic characteristics on these kinds of jointings. Distinctly in this research the effect of the bolts tightness degree and the magnitude of the vibration on the dynamic characteristics of the MERO connecting system has been experimentally evaluated. Therefore a member made by this system in the form of a cantilever beam at different degree of bolt tightness and by the free vibration method and by making initial displacement was experimented in order to determine the quantity of dynamic system parameters including the damping ratio, damping coefficient and the natural frequency. The results obtained showed that, the magnitude of bolt tightness is directly proportional to the structure vibration. Also the maximum damping ratio and damping coefficient occurs at 60 Nm bolt tightness, and if the tightness degree is more or less than this quantity, the magnitude of damping ratio and damping coefficient would be less than that. Also the results showed that there is a direct relation between the initial displacement with the damping, it means that by increasing the vibration amplitude the damping will increase and vice versa.


Main Subjects

[1] سوامی، راما؛ کاوه، علی؛ کروبی، فرهاد؛ یکوانی، جعفر؛ تحلیل،طراحی و ساخت ساز ههای فضایی فولادی، مرکز تحقیقات ساختمان و مسکن، تهران، چاپ اول، 1383 .
[2] قاسمی، میثم؛ مطالعه تجربی رابطه نیرو-تغ ییر مکان سیستم اتصالی MERO و بررسی اثر آن در پاسخ ساز ههای فضاکار دولایه تخت، پایان نامه کارشناسی ارشد مهندسی عمران، دانشگاه صنعتی بابل، 1387 .
[3] جیمین، هی؛ ژی فانگ، فو؛ ضیائ یراد، سعید؛ صالحی، مهدی؛ آنالیز مودال، انتشارات مؤسسه علمی دانش پژوهان برین، اصفهان، چاپ اول، 1384 .
[4] Lazan, B.; "Damping of Materials and Members in Structural Mechanics", Pergamon Press, p. 317, 1968.
[5] Chopra, A. K.; "Dynamics of Structures, Theory and Applications to Earthquake Engineering", 4th
Edition, Prentice Hall, 2011.
[6] Ebadi, M.; and Davoodi, M. R.; "Evaluate Axial Stiffness of the MERO Connection Under the Effect
of Hardening the Screw", International Journal Sci.Emerging Tech., Vol. 4, pp. 116-122, 2012.
[7] Souza, A.; Goncalves, R. M.; and Malite, M.;"Behaviour of Tubular Space Truss Connections with
Stamped End Bars", Journal of Space Structures, Vol.1, pp. 337-345, 2008.
[8] Fathelbab, F.; "The Effect of Joints on The Stability of Shallow Single Layer Lattice Domes", Ph.D. Thesis,
University of Cambridge, 270 pages, 1997.
[9] Caglayan, O.; and Yoksel, E.; "Experimental and Finite Element Investigation on The Collapse of
a MERO Space Truss Roof Structure", Journal of Engineering Failure Analysis, Vol. 15, pp. 458-470,2007.
[10] Androic, B.; "Deformations Observed On Systems Of long Span Space Trusses", International Journal of
Space Structures, Vol. 7, pp. 219-222, 2002.
[11] Davoodi, M. R.; Pashaei, M. H.; and Mostafavian, S. A.; "Experimental Study of the Effects of Bolt
Tightness on The Behaviour of MERO-Type Double Layer Grids", Journal of the International Association
for Shell and Spatial Structures (IASS), Vol. 48, pp.45-52, 2007.
[12] Pashaei, M. H.; Davoodi, M. R.; and Noshin, H.;"Effects of Tightness of Bolts on The Damping of a MERO-Type Double Layer Grid", International Journal of Space Structures", Vol. 21, pp. 103-110,2006.
[13] Pashaei, M. H.; and Asoor, A. A.; "Experimentally Study on The Effects of Type of Joint On Damping",
World Applied Sciences Journal, Vol. 8, pp. 608-613,2010.
[14] Celebi, M.; "Comparison of Damping in Buildings Under Low-Amplitude and Strong Motion", Journal of
Wind Engineering and Industrial Aerodynamics, Vol.59, pp. 309-323, 1999.
[15] Fukuwa, N.; Nishizaka, R.; Yagi, S.; Tanaka, K.; and Tumura, Y.; "Field Measurement of Damping and
Natural Frequency of Actual Steel-Framed Building Over a Wide Range of Amplitudes", Journal of Wind
Engineering and Industrial Aerodynamics, Vol. 59,pp. 325-347, 1999