Building structures with nonlinear response to external dynamic loading

Vestnik MGSU 11/2016
  • Pustovgar Andrey Petrovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Professor, Vice Rector for Research, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Korolev Evgeniy Valer’evich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Advisor of RAACS, Director, Research and Educational Center “Nanomaterials and Nanotechnologies”, Prorector, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 68-77

Construction compositions having nonlinear response to dynamic loading are compound compositions possessing disperse and liquid phases. They functionally comprise agents which give the composition the required properties depending on its aim and field of application. Under dynamic loadings such compositions are nonlinearly changed. Though such compositions are quite simple it is necessary to solve a number of tasks when developing their formula. The article considers scientific approaches to design of compound compositions aimed for operation under dynamic loadings. A composition model is proposed and analyzed. Basing on the analysis the formula parameters of the considered compositions are specified. The requirements to disperse and liquid phases are determined. The authors showed that the cancellation of the dependencies of quantity and strength on contacts from the diameter of disperse phase particles influences the strength of the considered compositions. It is noted that spot contact is formed when the layers of liquid phase which surround the contacting particles of the disperse phase merge. The features of the components are specified. The considered features should be preferred when choosing the disperse and liquid phases of compound compositions.

DOI: 10.22227/1997-0935.2016.11.68-77

Download

Account for the surface tension in hydraulic modeling of the weir with a sharp threshold

Vestnik MGSU 9/2014
  • Medzveliya Manana Levanovna - Moscow State University of Civil Engineering (MGSU) Candidate of Technical Sciences, Associate Professor, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 100-105

In the process of calculating and simulating water discharge in free channels it is necessary to know the flow features in case of small values of Reynolds and Weber numbers. The article considers the influence of viscosity and surface tension on the coefficient of a weir flow with sharp threshold. In the article the technique of carrying out experiments is stated, the equation is presented, which considers the influence of all factors: pressure over a spillway threshold, threshold height over a course bottom, speed of liquid, liquid density, dynamic viscosity, superficial tension, gravity acceleration, unit discharge, the width of the course. The surface tension and liquid density for the applied liquids changed a little. In the rectangular tray (6000x100x200) spillway with a sharp threshold was established. It is shown that weir flow coefficient depends on Reynolds number (in case Re < ~ 2000) and Webers number. A generalized expression for determining weir flow coefficient considering the influence of the forces of viscosity and surface tension is received.

DOI: 10.22227/1997-0935.2014.9.100-105

References
  1. Linford A. The Application of Models to Hydraulic Engineering – Reservoir Spillways. Water and Water Engineering. October, 1965, pp. 351—373.
  2. Engel F., Stainsby W. Weirs for Flow Measurement in Open Channels. Part 2. Water and Water Engineering. 1958, vol. 62, no. 747, pp. 190—197.
  3. Kindsvater C., Carter R. Discharge Characteristics of Rectangular Thin-plate Weirs. Transactions ASCE, 1957, vol. 122, pp. 772—822.
  4. Spronk R. Similitude des ecoulements Sur les deversoirs en mince paroi aux faibles charges. Rev. Univers. mines. 1953, vol. 3, no. 9, pp. 119—127.
  5. Hager W. Ausfluss durch vertikale offnungen. Wasser, Energ. Luft. 1988, vol. 80, no. 3—4, pp. 73—79.
  6. Al’tshul’ A.D., Medzveliya M.L. Ob usloviyakh otryva prilipshey strui na vodoslive s ostrym porogom [On the Conditions of Separating the Stuck Flood on the Weir with a Sharp Threshold]. Izvestiya vuzov: Stroitel’stvo [News of the Institutions of Higher Education]. 1991, no. 11, pp. 73—76.
  7. Medzveliya M.L., Pipiya V.V. Koeffitsient raskhoda vodosliva s shirokim porogom v oblasti malykh naporov [Discharge Ratio of the Broad-crested Weir Flow in the Low Head Area]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 4, pp. 167—171.
  8. Medzveliya M.L., Pipiya V.V. Usloviya obrazovaniya svobodnoy strui na vodoslive s ostrym porogom [Conditions of Formation of a Free Flow over a Sharp Crest Weir]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 1, pp. 185—189.
  9. Al’tshul’ A.D. Istechenie iz otverstiy zhidkostey s povyshennoy vyazkost’yu [Efflux of Liquids with Elevated Toughness]. Neftyanoe khozyaystvo [Oil Industry]. 1950, no. 2, pp. 55—60.
  10. Jameson A. Flow over Sharp-edged Weirs. Effect of Thickness of Crest . J. Inst. of Civil Engrs. Nov. 1948, vol. 31, no. 1, pp. 36—55. DOI: http://dx.doi.org/10.1680/IJOTI.1948.13377.
  11. D’Alpaos L. Sull’efflusso a stramazzo al di sopra di un bordo in parete sottile perpiccolshi valori del carico. Atti ist. Veneto sci lett. ed arti. Cl, sci mat. e natur. 1976—1977, vol. 135, pp. 169—190.
  12. Shchapov N.M. Gidrometriya gidrotekhnicheskikh sooruzheniy i gidromashin [Hydrometry of Hydraulic Engineering Structures and Hydraulic Units]. Moscow, Leningrad, Gosenergoizdat Publ., 1957, 235 p.
  13. Raju K.G.R., Asawa G.L. Viscosity And Surface Tension Effects On Weir Flow. J. of the Hydraulic Engineering, ASCE. 1977, vol. 103, no. 10, pp. 1227—1231.
  14. Rosanov N., Rosanova N. Some Problems of Modeling Water Outlet Structures with Free — Surface Flow. Proc. 19 IAHR congr. New-Delhi, 1981, vol. 5, pp. 81—91.
  15. Molitor D.A. Hydraulics of Rivers, Weirs and Sluices. 1st ed. New York : John Wiley & Sons; London : Chapman & Hall, Limited. 1908. 178 p.

Download

Warehouse premises and tank farms fire safety problem

Vestnik MGSU 10/2018 Volume 13
  • Anisimov Mikhail A - University of Maryland Distinguished University Professor, University of Maryland, College Park, MD 20742, USA.
  • Degaev Evgeniy N. - Moscow State University of Civil Engineering (National Research University) (MGSU) Associate Professor, Department of housing and communal complex, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 1243-1250

Introduction. Presented the approach to studying impact of foaming agent process solution shelf life on the surface activity and fire-extinguishing efficiency of foams. One of the most important problems in construction is to ensure fire safety of construction objects. Fires arising at industrial facilities and construction sites are always catastrophic, both for the economy and for the environment. Storage facilities and tanks in which various types of materials and substances, often toxic and fire-hazardous, can be stored are of particular danger. Addresses the problem of oil product warehouse premises and tank farms fire safety using foam extinguishing system. The problem consists in reduction of foaming agent concentration in the process solution during long-term storage. Concentration reduction is expressed in a surface activity decrease and in violation of spreading coefficient structure, namely, by an increase in surface and interfacial tension. Consequently, the use of foaming agent process solution for extinguishing fire at oil product warehouse premises and tank farms that is not capable of providing required foam expansion ratio and spreading coefficient for successful subsurface suppression of oil products flame. Materials and methods. Four brands of fluorinated foaming agents are tested according to the methods described in GOST R 50588-2012 “Foaming agents for fire extinguishing. General technical requirements and testing methods” and GOST R 53280.2-2010 “Automatic fire extinguishing units. Fire extinguishing agents. Part 2. Foaming agents for subsurface suppression of oil and oil products fires in tanks. General technical requirements and testing methods”. Results. The studies have shown that foam quality determining fire extinguishing capacity of foam extinguishing system changes over foaming agent process solution shelf life and depends on spreading coefficient structure, which is characterized by surface and interfacial tension values for foaming agent process solution. Conclusions. The process solutions made from modern (biologically soft) fluorinated foaming agents decrease in their surface activity over time and become unsuitable for oil products subsurface suppression. To maintain efficiency of the foam extinguishing system used to ensure fire safety of oil product warehouse premises and tank farms, age of the process solution in the circulating pipeline system should not exceed one day.

DOI: 10.22227/1997-0935.2018.10.1243-1250

Download

Results 1 - 3 of 3