scholarly journals Discussion: “Natural Frequency Determination of Long Span Floor Slabs” (Chadha, J., and Allen, D. L., 1972, ASME J. Eng. Ind., 94, pp. 660–664)

1972 ◽  
Vol 94 (2) ◽  
pp. 664-664
Author(s):  
H. Saunders
1972 ◽  
Vol 94 (2) ◽  
pp. 660-664 ◽  
Author(s):  
J. Chadha ◽  
D. L. Allen

This paper presents a general procedure for calculating the natural frequencies of rectangular plate structures which have beam stiffeners in the interior and at the boundaries. The technique of analysis accounts for shear deflections and rotary inertia of the plate. The effect of torsional and flexural reactions of the supporting beams on the plate-beam structure has also been included. The natural frequencies are compared with experimental values and also with those obtained by orthotropic plate approximation and Rayleigh’s method.


1993 ◽  
Vol 102 (5-6) ◽  
pp. 432-438 ◽  
Author(s):  
F. Nez ◽  
F. Biraben ◽  
R. Felder ◽  
Y. Millerioux

2018 ◽  
Vol 19 (01) ◽  
pp. 1940010 ◽  
Author(s):  
Yan-Chun Ni ◽  
Qi-Wei Zhang ◽  
Jian-Feng Liu

Modal identification aims at identifying the dynamic properties including natural frequency, damping ratio, and mode shape, which is an important step in further structural damage detection, finite element model updating, and condition assessment. This paper presents the work on the investigation of the dynamic characteristics of a long-span cable-stayed bridge-Sutong Bridge by a Bayesian modal identification method. Sutong Bridge is the second longest cable-stayed bridge in the world, situated on the Yangtze River in Jiangsu Province, China, with a total length of 2 088[Formula: see text]m. A short-term nondestructive on-site vibration test was conducted to collect the structural response and determine the actual dynamic characteristics of the bridge before it was opened to traffic. Due to the limited number of sensors, multiple setups were designed to complete the whole measurement. Based on the data collected in the field tests, modal parameters were identified by a fast Bayesian FFT method. The first three modes in both vertical and transverse directions were identified and studied. In order to obtain modal parameter variation with temperature and vibration levels, long-term tests have also been performed in different seasons. The variation of natural frequency and damping ratios with temperature and vibration level were investigated. The future distribution of the modal parameters was also predicted using these data.


Author(s):  
K. Bielska ◽  
S. Wójtewicz ◽  
P. Morzyński ◽  
P. Ablewski ◽  
A. Cygan ◽  
...  

Author(s):  
G. Satheesh Kumar ◽  
T. Nagarajan

Reconfiguration of Stewart platform for varying tasks accentuates the importance for determination of optimum geometry catering to the specified task. The authors in their earlier work (Satheesh et al., 2008) have indicated the non availability of an efficient holistic methodology for determining the optimum geometry. Further, they have proposed a solution using the variable geometry approach through the formulation of dimensionless parameters in combination with generic parameters like configuration and joint vector. The methodology proposed provides an approach to develop a complete set of design tool for any new reconfigurable Stewart platform for two identified applications viz., contour generation and vibration isolation. This paper details the experimental investigations carried out to validate the analytical results obtained on a developed Stewart platform test rig and error analysis is performed for contour generation. The experimental natural frequency of the developed Stewart platform has also been obtained.


1955 ◽  
Vol 11 ◽  
pp. 32-57 ◽  
Author(s):  
Emil W. Haury ◽  
Robert L. Rands ◽  
Albert C. Spaulding ◽  
Walter W. Taylor ◽  
Raymond H. Thompson ◽  
...  

The study of cultural stability requires a knowledge of cultural development over a reasonably long span of time. The definition of this time perspective is one of the major contributions of archaeology to the study of culture. The archaeologist therefore should be in a position to make a significant contribution to the appraisal of the stability problem itself. However, the lack of a commonly accepted anthropological definition of the concept of cultural stability imposes semantic difficulties which hinder the determination of practical limits for the stability- instability problem area. Moreover, the nature of the data available to the archaeologist conditions the kind of contribution he can make.


2019 ◽  
Vol 968 ◽  
pp. 330-341
Author(s):  
Talyat Azizov ◽  
Wit Derkowski ◽  
Nadzieja Jurkowska

The paper discusses the principles of precast concrete hollow-core slabs taking into account their spatial work. It is shown that consideration of spatial work makes it possible to determine the forces in individual floor slabs significantly more precise. The fact that strain redistribution between precast floor slabs depends on slabs’ bending and torsional stiffness is shown. The research has been mostly devoted to determination of the bending stiffness with regard to formation of cracks and the change in torsional stiffness, especially considering the presence of normal cracks, which is still unstudied. This paper presents the technique for determining the torsional stiffness of hollow-core slabs with normal cracks. In order to determine the components included in the resolving system of equations, it is proposed to use an approximation method based on the processing of numerical data using spatial finite elements.


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