81. A method for the calculation of lateral deflections of lattice towers

1993 ◽  
pp. 1: 755-765
Author(s):  
J. J. Cao ◽  
A. J. Bell
Keyword(s):  
Lattice Towers ◽  
Lateral Deflections

Laterally accreted deposits in low efficiency turbidites associated with a structurally-induced topography (Oligocene Molare Group, Tertiary Piedmont Basin, NW Italy)

2021 ◽  
Vol 91 (7) ◽  
pp. 751-772
Author(s):  
Roberto Tinterri ◽  
Andrea Civa
Keyword(s):  
Small Volume ◽  
Alternative Interpretation ◽  
Meandering Channels ◽  
Stratigraphic Framework ◽  
Sediment Gravity Flow ◽  
Dense Flows ◽  
Low Efficiency ◽  
Nw Italy ◽  
Cross Current ◽  
Lateral Deflections

ABSTRACT The origin of laterally accreted deposits in ancient deep marine successions is often controversial. Indeed, not always do these features imply the occurrence of meanders or high-sinuosity turbidite channels, but they can be generated by other causes, such as sediment-gravity-flow dynamics controlled by the morphology of tectonically confined mini-basins. This work discusses laterally accreted deposits composed of sharp-based, normally graded beds in a very small tectonically controlled mini-basin. These beds, characterized by a well-defined asymmetrical cross-current facies tract, form well-developed lateral-accretion surfaces dipping in directions ranging between W and SW, and perpendicular to the paleocurrents directed towards the N. For this reason, these deposits have always been interpreted as point bars related to meandering channels. A new detailed stratigraphic framework and facies analysis have led to an alternative interpretation, namely that these deposits record lateral deflections of small volume, longitudinally segregated turbidite dense flows against a structurally controlled morphological high. This interpretation is also supported by a comparison to other tectonically controlled turbidite systems that are characterized by higher degrees of efficiency but show similar laterally accreted deposits and cross-current facies tracts.

Bending of Pretwisted Beams

1955 ◽  
Vol 22 (3) ◽  
pp. 348-352
Author(s):  
J. Zickel
Keyword(s):  
General Theory ◽  
Bending Stiffness ◽  
Thin Strip ◽  
Principal Directions ◽  
Thin Walled ◽  
Lateral Deflections

Abstract The general theory of pretwisted beams and columns is applied to the bending of an initially straight and uniformly pretwisted beam of doubly symmetric thin-walled section. Pretwisting brings planes of various bending stiffness into play with a resulting stiffness which in a sense averages the stiffness of the beam in its principal directions. It is shown that compared with bending of an untwisted beam in its most flexible direction a thin strip can have its deflection in the plane of bending reduced 72 per cent by an initial twist of 0.83π. Simultaneously, however, lateral deflections of almost equal magnitude are induced. For pretwists above 2π, the lateral deflections become practically negligible and the deflections in the plane of bending are still reduced as much as 44 per cent. With increasing initial twist, however, the pretwisted beam becomes more flexible, and for an initial twist of 6.5π it is as flexible as the untwisted beam in its most flexible direction. Beams of equal flexibility in all directions simply become more flexible with initial twist, a fact which corresponds to the observations made by Den Hartog in some of his experiments.

Lateral deflections of circular plates

1999 ◽  
pp. 458-491 ◽  
Author(s):  
JOHN CASE ◽  
LORD CHILVER ◽  
CARL T.F. ROSS
Keyword(s):  
Circular Plates ◽  
Lateral Deflections

scholarly journals Lattice and Tubular Steel Wind Turbine Towers. Comparative Structural Investigation

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6325
Author(s):  
Nafsika Stavridou ◽  
Efthymios Koltsakis ◽  
Charalampos C. Baniotopoulos
Keyword(s):  
Wind Turbine ◽  
Leading Role ◽  
Increasing Trend ◽  
History Of ◽  
Wind Turbine Towers ◽  
Lattice Towers ◽  
New Generation ◽  
Installed Capacity ◽  
Tower Height ◽  
Wind Power Development

Renewable energy is expected to experience epic growth in the coming decade, which is reflected in the record new installations since 2010. Wind energy, in particular, has proved its leading role among sustainable energy production means, by the accelerating rise in total installed capacity and by its consistently increasing trend. Taking a closer look at the history of wind power development, it is obvious that it has always been a matter of engineering taller turbines with longer blades. An increase in the tower height means an increase in the material used, thereby, impacting the initial construction cost and the total energy consumed. In the present study, a numerical investigation is carried out in order to actively compare conventional cylindrical shell towers with lattice towers in terms of material use, robustness and environmental impact. Lattice structures are proved to be equivalently competitive to conventional cylindrical solutions since they can be designed to be robust enough while being a much lighter tower in terms of material use. With detailed design, lattice wind turbine towers can constitute the new generation of wind turbine towers.

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