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.

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

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

A Chaotification model based on sine and cosecant functions for enhancing chaos

2021 ◽  
Author(s):  
Yuqing Li ◽  
Xing He ◽  
Dawen Xia
Keyword(s):  
Fixed Point ◽  
Lyapunov Exponent ◽  
Chaotic Maps ◽  
Dynamic Properties ◽  
Chaotic Map ◽  
Sample Entropy ◽  
One Dimensional ◽  
Model Based ◽  
Chaotic Region ◽  
Definition Of

Chaotic maps with higher chaotic complexity are urgently needed in many application scenarios. This paper proposes a chaotification model based on sine and cosecant functions (CMSC) to improve the dynamic properties of existing chaotic maps. CMSC can generate a new map with higher chaotic complexity by using the existing one-dimensional (1D) chaotic map as a seed map. To discuss the performance of CMSC, the chaos properties of CMSC are analyzed based on the mathematical definition of the Lyapunov exponent (LE). Then, three new maps are generated by applying three classical 1D chaotic maps to CMSC respectively, and the dynamic behaviors of the new maps are analyzed in terms of fixed point, bifurcation diagram, sample entropy (SE), etc. The results of the analysis demonstrate that the new maps have a larger chaotic region and excellent chaotic characteristics.

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.

scholarly journals On the Analysis of New COVID-19 Cases in Pakistan Using an Exponentiated Version of the M Family of Distributions

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 953
Author(s):  
Rashad A. R. Bantan ◽  
Christophe Chesneau ◽  
Farrukh Jamal ◽  
Mohammed Elgarhy
Keyword(s):  
Statistical Models ◽  
Cumulative Distribution Function ◽  
Cumulative Distribution ◽  
Exponential Distributions ◽  
New Family ◽  
Proposed Model ◽  
Complete Study ◽  
Probability And Statistics ◽  
Definition Of ◽  
Analyze Data

This paper develops the exponentiated Mfamily of continuous distributions, aiming to provide new statistical models for data fitting purposes. It stands out from the other families, as it depends on two baseline distributions, with the use of ratio and power transforms in the definition of the main cumulative distribution function. Thanks to the joint action of the possibly different baseline distributions, flexible statistical models can be created, motivating a complete study in this regard. Thus, we discuss the theoretical properties of the new family, with emphasis on those of potential interest to the overall probability and statistics. Then, a new three-parameter lifetime distribution is derived, with the choices of the inverse exponential and exponential distributions as baselines. After pointing out the great flexibility of the related model, we apply it to analyze an actual dataset of current interest: the daily COVID-19 cases observed in Pakistan from 21 March to 29 May 2020 (inclusive). As notable results, we demonstrate that the proposed model is the best among the 15 top ranked models in the literature, including the inverse exponential and exponential models, several modern extensions of them depending on more parameters, and the “unexponentiated” version of the proposed model as well. As future perspectives, the proposed model can be of interest to analyze data on COVID-19 cases in other countries, for possible comparison studies.

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
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