Determination of the wind load on towers with a view to the effect of the service platforms

1986 ◽  
Vol 22 (10) ◽  
pp. 482-484
Author(s):  
B. S. Vol'fson ◽  
S. I. Zusmanovskaya
Keyword(s):  
2020 ◽  
Vol 82 (2) ◽  
pp. 215-224
Author(s):  
V.I. Erofeev ◽  
I.A. Samokhvalov

A numerical study of the survivability of the flange assembly is carried out upon reaching a critical load and in the presence of a defect in one of the design areas, taking into account the calculated values of the aerodynamic coefficients. An experiment is being carried out to determine the values of the wind load acting on the supporting legs of a metal tower. The calculation of the stressstrain state is performed using software system as SCAD Office and IDEA StatiCa 10.0. After calculating the forces in the core model of the structure, a threedimensional plate model of the assembly is formed and prepared for calculation. According to the results of the experiment, a graph was compiled with the values of aerodynamic coefficients, which were used in calculating the stressstrain state of the node. The analysis of the calculation results revealed that in the design (defectfree) state of the structure, the safety factor of the bearing units and elements is 35-40% (equivalent stresses were 165 MPa). If there is a defect in the metal structures of the belt in the region of the flange, the equivalent stresses increase to 247.6 MPa in the region of the cleavage (defective hole), thus, the margin in bearing capacity drops to 0.4%. As a result of the assessment of the survivability of the flange connection, it was revealed that the connection has a high potential survivability, in turn, the flange itself is able to work in the presence of some defects without reducing its bearing capacity to a critical level. The aerodynamic coefficients obtained in this work will determine the wind load on this type of profile and can be used in design calculations of tower structures for wind loads.


1977 ◽  
Vol 13 (11) ◽  
pp. 1125-1129
Author(s):  
L. F. Vashchenko
Keyword(s):  

Author(s):  
Y.O. Bessmertnyi ◽  
◽  
V.L. Krasovsky ◽  

The process of deformation and buckling of shallow thin-walled elastic conical shells has been investigated for the case of significantly non-uniform stress-strain state due to the action of wind load based on improved model of pressure application schema to the surface of shallow shell and for hinged hedge of border. An improved model of wind load was based on data presented in terms [5, 6] and was a logical continuation of previous investigation of wind action on shallow conical shells based on model of first approach [3]. Deformation and buckling process investigation has been carried out using software ANSYS which effectivity was approved by the fact of being used by NASA for its aerospace projects. A model of shallow conical shell has been made using four-corner finite element SHELL 281 with 8 nodes that let us obtain not only symmetrical relatively to the axis of rotation buckling form but an asymmetrical too. Two types of computation have been made during numerical modeling – linear bifurcation computation with determination of linear pressure qcr value and corresponding to it buckling form, and computation of geometrically non-linear problem of deformation with determination of limit pressure qlim and corresponding buckling form. Obtained buckling forms have been compared to the deformed shape of shell surface when aerodynamic computations have been carried out using software ANSYS. An estimation analysis has been made for case of application of improved model of wind load in comparison to the previous investigation according to the values of baring capacity and buckling shape coherence during resolution of static tasks and comparison to the results of aerodynamic solution. An analysis of base parameter influence has been carried out for the model of first approach and current improved model according to the bearing capacity value and local extremums on schema of pressure intensity distribution of wind load. Specific moments of deformation process computations based on improved model using environment ANSYS have been mentioned and of further analysis on the basis of improved model with it specifics have been given too.


2020 ◽  
Vol 313 ◽  
pp. 00050
Author(s):  
Olga Hubova ◽  
Michal Franek ◽  
Marek Macak

The article deals with aerodynamic study of solar panel assemblies. Experimental measurements were realized in BLWT wind tunnel. The aim of the solution was to determine the maximum pressure and suction wind load on top and bottom surfaces of panels. The resulting net pressure coefficient represents the maximum local pressure in each panel row as maximum values from all wind directions. The experimentally obtained cp,net values were compared with the conservative values in EN 1991-1-4 for open monopitch canopies. A lower wind load in the inner regions of the triangular assemblies should be used in the design of fixing supports.


Author(s):  
Muthomi Munyua

This paper provides guidance on the use of existing wind data in Kenya with the Eurocodes despite the absence of the local national annexes. The determination of wind loads in the structural design of buildings according to the Eurocode Standard KS EN 1991-1-4:2005 in Kenya is challenging because of the lack of the Kenya National Annex. The design code commonly used in Kenya is CP3-Chapter V-2:1972 that uses the three-second gust duration. This gust duration results in higher magnitudes of wind loads that end up making the structures unnecessarily robust and uneconomical. Using the Eurocodes has the promise of achieving more economical designs because it uses the 10-minute gust duration. The 10-minute gust duration results in typically lower magnitudes of wind loads than the three-second gust duration for the same wind speed. Kenya adopted the Eurocodes in September 2012 but has not yet developed its national annexes opting instead to use the UK National Annexes. The UK National Annexes are applicable to Kenya in some scenarios but not in others such as wind loading. The lack of the Kenya National Annexes has led to difficulties in the adoption of the Eurocodes. This paper outlines a procedure in which the existing wind data given in three-second gusts could be converted to 10-minute wind speeds. Once converted, the method described in the UK National Annex could then be followed selectively to determine the wind load on a structure. Lastly, the paper recommends that wind data collected from 1977 to 2021 by the Kenya Meteorological Department be incorporated to the development of the wind map for the Kenya National Annex to KS EN 1991-1-4:2005


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