Main Principles of Vibrodamped Structure Scale Models for the Whole Sound Frequency Range

1995 ◽  
Author(s):  
Alexei V. Ionov
Keyword(s):  
Physical Modelling ◽  
Energy Difference ◽  
Full Scale ◽  
Sound Frequency ◽  
Frequency Range ◽  
Vibration Load ◽  
Scale Modeling ◽  
Physical Scale ◽  
Scale Models ◽  
Dynamic Rigidity

Abstract At low and middle sound frequencies the physical modelling of vibro-absorbing constructions is interpreted as a reconstruction of a frequency dependence of an imaginary part of a full-scale construction dynamic rigidity which is shifted in frequency according to a scale factor. For the high sound frequency range there is a dimensionless form of a matrix energy equation. It allows the task of physical scale modeling to be formulated as a reconstruction of a vibration energy difference between structure elements excited by an external vibration load and the others its elements as in a full-scale object. The analysis is fulfilled in the specially selected frequency bands when the geometrical similarity between scale and full-scale constructions and a number of demands to their material and the loss factors are observed.

Physical Scale Modeling the Millimeter-Wave Backscattering Behavior of Ground Clutter

2001 ◽  
Author(s):  
A. J. Gatesman ◽  
T. M. Goyette ◽  
J. C. Dickinson ◽  
J. Waldman ◽  
J. Neilson ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Ground Clutter ◽  
Scale Modeling ◽  
Physical Scale

Physical Scale Modeling of VHF/UHF SAR Collection Geometries

2004 ◽  
Author(s):  
C. Beaudoin ◽  
A. Gatesman ◽  
M. Clinard ◽  
J. Waldman ◽  
R. Giles ◽  
...  
Keyword(s):  
Scale Modeling ◽  
Physical Scale

scholarly journals Roughness Lengths for Momentum and Heat Derived from Outdoor Urban Scale Models

2007 ◽  
Vol 46 (7) ◽  
pp. 1067-1079 ◽  
Author(s):  
M. Kanda ◽  
M. Kanega ◽  
T. Kawai ◽  
R. Moriwaki ◽  
H. Sugawara
Keyword(s):  
Wind Direction ◽  
Roughness Length ◽  
Scale Dependence ◽  
Scale Model ◽  
Small Scale ◽  
Physical Scale ◽  
Scale Models ◽  
Roughness Lengths ◽  
Urban Sites ◽  
Obstacle Height

Abstract Urban climate experimental results from the Comprehensive Outdoor Scale Model (COSMO) were used to estimate roughness lengths for momentum and heat. Two different physical scale models were used to investigate the scale dependence of the roughness lengths; the large scale model included an aligned array of 1.5-m concrete cubes, and the small scale model had a geometrically similar array of 0.15-m concrete cubes. Only turbulent data from the unstable boundary layers were considered. The roughness length for momentum relative to the obstacle height was dependent on wind direction, but the scale dependence was not evident. Estimated values agreed well with a conventional morphometric relationship. The logarithm of the roughness length for heat relative to the obstacle height depended on the scale but was insensitive to wind direction. COSMO data were used successfully to regress a theoretical relationship between κB−1, the logarithmic ratio of roughness length for momentum to heat, and Re*, the roughness Reynolds number. Values of κB−1 associated with Re* for three different urban sites from previous field experiments were intercompared. A surprising finding was that, even though surface geometry differed from site to site, the regressed function agreed with data from the three urban sites as well as with the COSMO data. Field data showed that κB−1 values decreased as the areal fraction of vegetation increased. The observed dependency of the bulk transfer coefficient on atmospheric stability in the COSMO data could be reproduced using the regressed function of Re* and κB−1, together with a Monin–Obukhov similarity framework.

Dynamic deformability evaluated by series of shaking table tests of full-scale models of masonry houses

2016 ◽  
pp. 2417-2424
Author(s):  
T. Hanazato ◽  
H. Seno ◽  
Y Niitsu ◽  
H. Imai ◽  
T. Narafu ◽  
...  
Keyword(s):  
Full Scale ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Scale Models

Failure tests on full-scale models of grout laminated wood decks

2004 ◽  
Vol 31 (1) ◽  
pp. 133-145 ◽  
Author(s):  
Aftab A Mufti ◽  
Baidar Bakht ◽  
Dagmar Svecova ◽  
Vidyadhar Limaye
Keyword(s):  
Load Distribution ◽  
Full Scale ◽  
Bottom Surface ◽  
Distribution Characteristics ◽  
Flat Bottom ◽  
The Third ◽  
Scale Models ◽  
Lower Load ◽  
Load Tests ◽  
The University

Grout laminated wood decks (GLWDs), representing the third generation of stressed wood decks, comprise either laminates or logs trimmed to obtain two parallel faces. The logs or laminates, running along the span, are held together by means of transverse internal grout cylinders that may be in either compression or tension. Two full-scale models of GLWD were constructed at Dalhousie University, Halifax, one with grout cylinders in compression and the other with the cylinders in tension. Service load tests conducted in Halifax showed that the former deck had better load distribution characteristics. Two years after the tests in Halifax, the models were shipped to The University of Manitoba in Winnipeg, where they were tested to failure under a central patch load. Because of miscommunication with the supplier, the logs of the GLWD with grout cylinders in compression were also trimmed to the third face that was kept at the bottom of the deck. The failure tests showed that despite its superior load distribution characteristics, the deck with grout cylinders in compression failed at a significantly lower load than the GLWD with cylinders in tension. It is argued that a planar surface in the logs at the flexural tension face not only reduces their flexural stiffness but also brings the defects of wood to the surface with maximum stress. The deck with the flat bottom surface underwent tension failure of the most heavily loaded logs, whereas the deck with the intact round surface of the logs at both top and bottom failed by horizontal splitting of all the logs.Key words: articulated plate, bridge deck, grout laminated deck, orthotropic plate, timber.

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