Structural dynamic properties of pentahaptocyclopentadienylmetal dicarbonyl dimers

1972 ◽  
Vol 11 (4) ◽  
pp. 671-676 ◽  
Author(s):  
J. G. Bullitt ◽  
F. A. Cotton ◽  
T. J. Marks
Keyword(s):  
Dynamic Properties ◽  
Structural Dynamic

OMA Study on the Structural Dynamic Properties of a Launcher Vehicle Using Flight Data

2017 ◽  
Author(s):  
Marco Eugeni ◽  
Giuliano Coppotelli ◽  
Franco Mastroddi ◽  
Paolo Gaudenzi ◽  
Stephan Muller ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Structural Dynamic ◽  
Flight Data

Highrise building characteristics and responses determined from nuclear seismology

1972 ◽  
Vol 62 (2) ◽  
pp. 519-540 ◽  
Author(s):  
John A. Blume
Keyword(s):  
Ground Motion ◽  
Dynamic Properties ◽  
Spectral Response ◽  
Earthquake Ground Motion ◽  
Structural Dynamic ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Nuclear Events ◽  
San Fernando ◽  
And Behavior

abstract Reliable measurements and detailed analyses of the responses of many buildings to ground motion resulting from underground nuclear explosions are providing new and valuable information on the structural-dynamic properties and behavior of real buildings. Much, if not all, of this knowledge is applicable to the problem of resisting natural earthquake ground motion, and it is being obtained as a byproduct of the AEC underground explosive nuclear safety program which is concerned with developing techniques for making reliable predictions of response and any damage. Information is provided on oscillator spectral response values, building responses, modal contributions and combinations versus elapsed time and at times of maximum response, variations in natural periods, foundation material interaction, and biaxial motion in the horizontal plane. Data are shown for nuclear events JORUM and HANDLEY and then compared to those of prior major events. In addition, peak responses of certain Las Vegas buildings to the distant February 1971 San Fernando earthquake (U.S. Geological Survey, 1971) are provided and compared to responses to nuclear events.

Serviceability Assessment of Footbridges via Improved Interval Analysis

2021 ◽  
Author(s):  
Roberta Santoro ◽  
Alba Sofi ◽  
Federica Tubino
Keyword(s):  
Interval Analysis ◽  
Dynamic Properties ◽  
Comfort Level ◽  
Cumulative Distribution ◽  
Gaussian Random Process ◽  
Spectral Moments ◽  
Traffic Condition ◽  
Structural Dynamic ◽  
Efficient Alternative ◽  
Definition Of

Abstract This paper studies the propagation of uncertainties on serviceability assessment of footbridges in unrestricted traffic condition based on a non-deterministic approach. Multi-pedestrian loading is modeled as a stationary Gaussian random process through the Equivalent Spectral Model [1] which yields analytical expressions of the spectral moments of the footbridge dynamic response. The uncertain pedestrian-induced loading parameters and structural dynamic properties are modeled as interval variables. An approximate analytical procedure, based on the Improved Interval Analysis [2], is introduced as an efficient alternative to classical optimization in order to propagate interval uncertainties. The presented procedure allows us to derive closed-form expressions of the bounds of the spectral moments of the response, as well as of the expected value and cumulative distribution function of the maximum footbridge acceleration. Two strategies are proposed to assess footbridges' serviceability. The first one leads to the definition of a range of comfort classes. The second strategy enables us to estimate an interval of probability of reaching at least a suitable comfort level.

Detection of Damage Extension in Cantilever Beams Using Change Ratio of Frequency Response Functions

2011 ◽  
Vol 50-51 ◽  
pp. 875-879
Author(s):  
Hai Lei Jia ◽  
Yin Zhao
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Damage Index ◽  
High Sensitivity ◽  
Cantilever Beams ◽  
Response Functions ◽  
Full Spectrum ◽  
Structural Dynamic ◽  
Low Dimensional

Frequency response function (FRF) is a fundamental dynamic index, which is capable of reflecting structural dynamic properties using full-spectrum information. In spite of distinct merits over conventional modal parameters, the FRF has an observable drawback of multi-dimensionality, unsuited for damage characterization. Such a situation motivates an interesting subject, i.e., extracting low-dimensional, high-sensitivity damage index from the FRF. This study focuses on developing a valid damage index, called FRF change ratio, to detect extension of damage. An experiment towards cantilever beams is systemically conducted. The results show that the FRF change ratio can effectively reflects damage extension, and it is more sensitive than conventional natural frequencies. This new damage index holds promise for practical damage detection in beam-like structures.

TEMPERATURE EFFECT ON THERMOMECHANICAL PROPERTIES OF BERYLLIUM CHALCOGENIDES BeS, BeSe AND BeTe

2006 ◽  
Vol 20 (01) ◽  
pp. 49-61 ◽  
Author(s):  
F. BENKABOU
Keyword(s):  
Elastic Constants ◽  
Dynamic Properties ◽  
Theoretical Calculations ◽  
Thermomechanical Properties ◽  
Structural Dynamic ◽  
Experimental Values ◽  
Beryllium Chalcogenides ◽  
Increasing Temperature ◽  
And Diffusion ◽  
Good Agreement

We have used the molecular-dynamic method for the calculation of the structural, dynamic and elastic properties of group BeS , BeSe and BeTe compounds for temperature ranging from 300 to 1200 K. Tersoff potential has been used to model the interaction between the groups II–VI compound atoms. The structural properties of cubic BeS , BeSe and BeTe have been calculated, and good agreement between the calculated and experimental values have been found. We have also predicted the elastic constants and diffusion coefficients of BeS , BeSe and BeTe . The values found compare very well with the theoretical results. For the temperature range under study, all elastic constants and dynamic properties show a softening with increasing temperature very similar to the theoretical calculations.

Structural, Dynamic Properties of Key Residues in Aβ Amyloidogenesis: Implications of an Important Role of Nanosecond Timescale Dynamics

ChemBioChem ◽  
2007 ◽  
Vol 8 (11) ◽  
pp. 1251-1254 ◽  
Author(s):  
Kwang Hun Lim ◽  
Ginger L. Henderson ◽  
Abhishek Jha ◽  
Martti Louhivuori
Keyword(s):  
Dynamic Properties ◽  
Structural Dynamic ◽  
Key Residues

Shaking Table Experimental Study on Damage Mechanism of the Disconnecting Switch under Seismic Excitation

2011 ◽  
Vol 488-489 ◽  
pp. 351-354
Author(s):  
Paweł Dembowski ◽  
Robert Jankowski
Keyword(s):  
High Voltage ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Safety Issue ◽  
Damage Mechanism ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Structural Dynamic ◽  
Electric Circuits ◽  
Seismic Tests

The efficiency of the energetic network is a very import safety issue in the region experienced by the earthquake. High voltage disconnecting switches are important elements of the energetic infrastructure used to separate electric circuits (i.e. during repairs), which should not be damaged remaining fully operational. The aim of the paper is to show the results of the shaking table experimental investigation focused on damage mechanism of a high voltage disconnecting switch under seismic excitation. The real example of the two-column pantograph-type disconnecting switch was considered in the study. First, the tests were carried out by exciting the unit with the sweep-sine function. Based on the results, the structural dynamic properties of undamaged structure (natural frequencies, damping ratios) could be determined. Then, the so called rumbling seismic tests were conducted in order to determine the seismic strength of disconnecting switch according to the standards PN-EN 60068-3-3. After each experiment, the sweep-sine test was carried out so as to check the decrease in the natural frequencies of the unit. The results of the study show that the lower parts of the columns, which serve as isolators, are the most critical locations of the disconnecting switch considered. The unit was damaged due to failure of one of the rotational mechanisms installed at the bottom of columns.

Influence Analysis of Layout of Braces on Structural Dynamic Properties of Large Space Multi-Storey Buildings

2012 ◽  
Vol 226-228 ◽  
pp. 901-904
Author(s):  
Jin Zhu Yu ◽  
Ping Zhou Cao ◽  
Kai Wu ◽  
Ming Bao Min
Keyword(s):  
Dynamic Properties ◽  
Steel Frame ◽  
Lateral Stiffness ◽  
Large Space ◽  
Structural Dynamic ◽  
Influence Analysis ◽  
Section Size ◽  
Object Parameters ◽  
Frame Construction

Taking a six-storey steel frame construction as the research object, parameters under study are the horizontal space of braces’ nodes and the layout of vertical braces. Based on the analysis of the structural period, layer displacement and angles of storey drift, research on the influence of layout of braces on structural dynamic properties of large space buildings is conducted. The results show that when column spacing is larger, braces-setting contributes to significantly improve the structure’s lateral stiffness and reduce the section size of columns, and that the section size of braces can be reduced by shortening the horizontal space of braces’ nodes. Braces should be set between the columns as full as possible. It is better to set the vertical braces positioned in the center instead of on the side between the columns. The lateral stiffness is higher when braces are set concentratedly than dispersedly. It’s more economical to set the inclined braces uniformly.

Updating of Finite Element Model in Considering Mode Errors with Fuzzy Theory

2009 ◽  
Vol 413-414 ◽  
pp. 785-792 ◽  
Author(s):  
Yang Liu ◽  
Zhong Dong Duan ◽  
Hui Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Fuzzy Theory ◽  
Dynamic Properties ◽  
Fuzzy Model ◽  
Element Model ◽  
Structural Dynamic ◽  
Fuzzy Variables ◽  
Design Variables

Finite element model updating aims at reconciling the analytical model with the test one, to acquire a refined model with high-fidelity in structural dynamic properties. However, testing data are inevitable polluted by noises. In this study, the mode parameters and design variables are modeled as fuzzy variables, and a fuzzy model updating method is developed. Instead of a single optimal model, a set of satisfactory models is obtained. The most physically compatible solution is sorted by insights to the structures. The proposed method is applied to a real concrete bridge, for which a physically meaningful model is identified.

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