Effect of guy cable constraint on structural damping of open lattice antenna towers

1980 ◽  
Vol 7 (4) ◽  
pp. 614-620
Author(s):  
J. S. Kennedy ◽  
D. J. Wilson ◽  
P. F. Adams ◽  
M. Perlynn
Keyword(s):  
Natural Frequencies ◽  
Damping Ratio ◽  
Field Tests ◽  
Full Scale ◽  
Structural Damping ◽  
Scale Field ◽  
Modes Of Vibration

This paper presents the results of full-scale field tests on two steel guyed latticed towers. The towers were approximately 83 m in height, were guyed at three levels, and were of bolted angle construction. The observed results consist of the natural frequencies of the first two modes of vibration as well as the damping ratio for the first mode. The observed results are compared with analytical predictions and observations made concerning the contributions of structural and cable action to the damping ratio.

Rockfall Full Scale Field Tests

2013 ◽  
pp. 461-467
Author(s):  
Alberto Clerici ◽  
Ezio Giuriani ◽  
Danilo Cambiaghi ◽  
Antonio Isceri ◽  
Giorgio Vassena ◽  
...  
Keyword(s):  
Field Tests ◽  
Full Scale ◽  
Scale Field

A Full Scale Test for Acoustic Fatigue in Pipework

2006 ◽  
Author(s):  
H. G. D. Goyder ◽  
K. Armstrong ◽  
L. Billingham ◽  
M. J. Every ◽  
T. P. Jee ◽  
...  
Keyword(s):  
Gas Flow ◽  
Static Pressure ◽  
Natural Frequencies ◽  
Full Scale ◽  
Oil Field ◽  
Structural Damping ◽  
Full Scale Test ◽  
Scale Test ◽  
Flow Through ◽  
Acoustic Fatigue

Gas flow through a corrugated pipe can produce unacceptable levels of noise. The occurrence of such noise gave rise to concerns about vibration induced fatigue of small-bore subsea pipework in the Schiehallion oil field. In order to check that the subsea pipework was free from noise-induced vibration a full scale replica of the subsea equipment containing the small-bore pipework was built and tested. The test required the generation of acoustic pressures with a 1 bar amplitude and a frequency range of 80 to 800Hz. It was also necessary to arrange for resonant conditions within the pipework and for acoustic nodes and anti-nodes to be swept though a range of possible locations. The test was conducted with full-scale conditions of methane at a static pressure of 170bar and with a range of gas flow rates. Particular attention was given to achieving the correct acoustic and structural natural frequencies together with the correct acoustic and structural damping ratios. The subsea equipment was found to be vulnerable for one operating condition. This vulnerability was removed by retro-fitting a brace to the existing subsea pipework.

Natural Frequencies and Damping of a Full-Scale Pipe Loop in Air and Water

2017 ◽  
Author(s):  
Hugh Goyder
Keyword(s):  
Oil And Gas ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Full Scale ◽  
Surrounding Water ◽  
Sea Floor ◽  
Dry Conditions ◽  
Vibration Tests ◽  
Complex Manner ◽  
Submerged Conditions

A full scale pipework system, typical of oil and gas installations located on the sea floor, was subjected to vibration tests in both dry and submerged conditions. The frequency range examined covered 10 Hz to 500 Hz. The objective of the tests was to provide experimental data so that computer simulations could be developed and validated. The method used to determine the vibration properties was that of an experimental modal analysis using an impact hammer. The hammer was modified for underwater use. In dry conditions the damping was found to be very small (damping ratio less than 0.0002) despite the construction being typical. When submerged the effect of the surrounding water was significant. The changes in the natural frequencies from the dry case to the wet case occurred in such a complex manner that it was not possible to identify a simple shift between wet and dry vibration modes. It was necessary to include appropriate added mass coefficients in the computer simulation for both the pipe and the support system. The effect of the surrounding water on the damping was measured but found to be insignificant. It was concluded that immersion in water does not add significant damping to oil and gas pipework.

Full-scale field tests for bridging sinkholes using flexible steel components as reinforcement

2012 ◽  
Vol 27 (2) ◽  
pp. 161-165
Author(s):  
Daniel Flum ◽  
Armin Roduner ◽  
John Kalejta
Keyword(s):  
Field Tests ◽  
Full Scale ◽  
Scale Field

scholarly journals Dynamic Property of a New Type of Postearthquake Temporary Prefabricated Lightweight Steel Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
GuoQi Xing ◽  
Qing-hai Li ◽  
JingJie Yu ◽  
Wei Xuan
Keyword(s):  
Finite Element ◽  
Experimental Model ◽  
Dynamic Property ◽  
Natural Frequencies ◽  
Damping Ratio ◽  
Steel Structure ◽  
Full Scale ◽  
Test Method ◽  
Lightweight Steel ◽  
New Type

For a new type of postearthquake temporary prefabricated lightweight steel structure proposed in this paper, mainly composed of steel frame, prefabricated hanger slabs, prefabricated hanger columns, reinforced concrete superposed slabs, etc., parameters of dynamic property for the structure, including natural frequency, vibration mode, damping ratio, etc., are determined by the test method. For prefabricated hanger columns and prefabricated hanger slabs, they are all produced with construction waste in factory and assembled on-site, which can form exterior walls. The united method, based on forced vibration method and ambient random vibration method, can quickly obtain accurate natural frequencies of the full-scale two-story experimental model. In this paper, damping oscillatory method is used to obtain damping ratio which can be determined only by the test method. In order to analyse the modal of the experimental model, a finite element model for the full-scale two-story experimental model is established, where the weight of prefabricated hanger slabs is assumed to be supported by prefabricated hanger columns, and the stiffness of prefabricated hanger columns is also increased. In addition, the connections between lightweight steel frame and prefabricated hanger columns are regarded as flexible connection. Comparing natural frequencies obtained from the finite element method with that obtained from the test method, magnification factor of stiffness for prefabricated hanger column is determined. In the analysis of modal for the full-scale two-story experimental model, the results show that the experimental model satisfies the requirement of design for seismic performance.

Full-Scale Field Tests of Discrete Fiber-Reinforced Sand

2002 ◽  
Vol 128 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Jeb S. Tingle ◽  
Rosa L. Santoni ◽  
Steve L. Webster
Keyword(s):  
Field Tests ◽  
Full Scale ◽  
Fiber Reinforced ◽  
Reinforced Sand ◽  
Scale Field ◽  
Discrete Fiber
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