Corrective Analysis of the Parametric Values from Dynamic Testing on Stand of the Antiseismic Elastomeric Isolators in Correlation with the Real Structural Supporting Layout

2013 ◽  
Vol 430 ◽  
pp. 305-311 ◽  
Author(s):  
Polidor Bratu
Keyword(s):  
Base Isolation ◽  
Dynamic Testing ◽  
Complete System ◽  
Viscoelastic Behavior ◽  
Hysteresis Loops ◽  
Added Mass ◽  
The Real ◽  
Equivalent Damping ◽  
Experimental Laboratory ◽  
The Time Domain

The paper presents the result of experimental research of the viscoelastic behavior of the antiseismic elastomeric isolators on stand, in laboratory, where the excitation is given only through harmonic instantaneous displacements. Based on the dynamic response under the form of the elastic and dissipation forces, in the time domain, the hysteresis loops and the stiffness, damping and durability to imposed repeated cycles parameters are determined. In this case, the order I dynamic system is free of added mass which makes the evaluation of its own damping to be estimated as equivalent damping with that of a complete system of 2ndorder with viscous damping.Using elastomeric isolators on site, for a base isolation project, either building or viaduct, imposes corrections of the experimental laboratory values considering the real conditions, function of the dynamic inertial excitation (earthquake, wind gusts, etc.) and of the response in instantaneous displacements.

scholarly journals Polymeric Bearings as a new base isolation system suitable for mitigating machine-induced vibrations

2018 ◽  
Vol 211 ◽  
pp. 17001 ◽  
Author(s):  
Tomasz Falborski ◽  
Robert Jankowski
Keyword(s):  
Base Isolation ◽  
Excitation Frequency ◽  
Hysteresis Loops ◽  
Shaking Table ◽  
Damping Properties ◽  
Structural Vibrations ◽  
Isolation System ◽  
Equivalent Damping ◽  
Flexible Polymer ◽  
Base Isolation System

The present paper summarizes the preliminary results of the experimental shaking table investigation conducted in order to verify the effectiveness of a new base isolation system consisting of Polymeric Bearings in reducing strong horizontal machine-induced vibrations. Polymeric Bearing considered in the present study is a prototype base isolation system, which was constructed with the use of a specially prepared flexible polymer with improved damping properties. Dynamic oscillatory tests, during which a concrete base slab supported by four Polymeric Bearings was subjected to horizonal sinusoidal excitations characterized by different frequencies and amplitudes, were conducted in order to determine the damping properties of Polymeric Bearings and their effectiveness in mitigating structural vibrations. Equivalent damping ratios for every excitation frequency considered were determined using the experimentally obtained hysteresis loops. Final conclusions are presented and the results discussed.

scholarly journals Broadband spectroscopy of astrophysical ice analogues

2019 ◽  
Vol 629 ◽  
pp. A112 ◽  
Author(s):  
B. M. Giuliano ◽  
A. A. Gavdush ◽  
B. Müller ◽  
K. I. Zaytsev ◽  
T. Grassi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Far Infrared ◽  
Infrared Region ◽  
Thz Radiation ◽  
The Real ◽  
Thz Range ◽  
The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

Hysteresis Loops of Base Isolation System - An Overview

2021 ◽  
Vol 879 ◽  
pp. 189-201
Author(s):  
M.A. Amir ◽  
N.H. Hamid
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Base Isolation ◽  
Numerical Models ◽  
Hysteresis Loops ◽  
Human Beings ◽  
Rc Buildings ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Systems

Recently, there are a lot of technological developments in the earthquake engineering field to reduce structural damage and one of them is a base isolation system. The base isolation system is one of the best technologies for the safety of human beings and properties under earthquake excitations. The aim of this paper is to review previous research works on simulation of base isolation systems for RC buildings and their efficiency in the safety of these buildings. Base isolation decouples superstructure from substructure to avoid transmission of seismic energy to the superstructure of RC buildings. The most effective way to assess the base isolation system for RC building under different earthquake excitations is by conducting experiment work that consumes more time and money. Many researchers had studied the behavior of base isolation system for structure through modeling the behavior of the base isolation in which base isolator is modeled through numerical models and validated through experimental works. Previous researches on the modeling of base isolation systems of structures had shown similar outcomes as the experimental work. These studies indicate that base isolation is an effective technology in immunization of structures against earthquakes.

Viscoelastic behavior of 1,3,5 tri α-naphthyl benzene (will the real TαNB please stand up)

1999 ◽  
Vol 110 (21) ◽  
pp. 10445-10451 ◽  
Author(s):  
Donald J. Plazek ◽  
Joseph H. Magill ◽  
I. Echeverrı́a ◽  
In-Chul Chay
Keyword(s):  
Viscoelastic Behavior ◽  
The Real

Ebatronics: A New Paradigm for Experimental Laboratory in Applied Science and Technology

2021 ◽  
Vol 03 (04) ◽  
Author(s):  
Maide Bucolo ◽  
Arturo Buscarino ◽  
Luigi Fortuna ◽  
Salvina Gagliano
Keyword(s):  
Science And Technology ◽  
Applied Science ◽  
New Paradigm ◽  
Recycled Materials ◽  
New Approach ◽  
The Real ◽  
Preliminary Results ◽  
Experimental Laboratory ◽  
Laboratory Experiences ◽  
First Time

In this paper, the main concepts and the preliminary results related to a new approach for creating innovative green laboratory experiences in applied science and technology will be discussed. The term ebatronics is here introduced for the first time in the literature to indicate a kind of experimental laboratory based on the conjunction of wooden recycled materials and microcontroller based devices. In particular, tensegrity based systems are presented. A gallery of prototypes developed by the authors is shown. An intense set of photos will illustrate the real effectiveness of the proposed laboratory project.

Radiation in Materials

2019 ◽  
pp. 303-365
Author(s):  
Richard Freeman ◽  
James King ◽  
Gregory Lafyatis
Keyword(s):  
Magnetic Fields ◽  
Time Domain ◽  
Measurement Techniques ◽  
Group Versus ◽  
Index Of Refraction ◽  
The Real ◽  
Versus Phase ◽  
Fundamental Relationship ◽  
Electric And Magnetic Fields ◽  
The Time Domain

The interaction of electromagnetic radiation and matter is examined, specifically electric and magnetic fields in materials with real and imaginary responses: under certain conditions the fields move through the material as a wave and under others they diffuse. The movement of a pulse of radiation in dispersive materials is described in which there are two wave velocities: group versus phase. The reflection of light from a sharp interface is analyzed and the Fresnel reflection/transmission equations derived. The response of materials to applied electric and magnetic fields in the time domain are correlated to their frequency response of the material’s polarization. The generalized Kramers–Kronig equations are derived and their applicability as a fundamental relationship between the real and imaginary parts of any material’s polarizability is discussed in detail. Finally, practical measurement techniques for extracting the real and imaginary components of a material’s index of refraction are introduced.

Combustion Turbine Deposition Observations From Residual and Simulated Residual Oil Studies

1982 ◽  
Author(s):  
G. A. Whitlow ◽  
S. Y. Lee ◽  
P. R. Mulik ◽  
R. A. Wenglarz ◽  
T. P. Sherlock ◽  
...  
Keyword(s):  
Vanadium Pentoxide ◽  
Field Experience ◽  
Dynamic Testing ◽  
Solid Particles ◽  
Residual Oil ◽  
Deposition Rates ◽  
Inertial Impaction ◽  
The Real ◽  
Combustion Gases ◽  
Current Utility

Burning residual oil in utility combustion turbines and the consequent deposition on blades and vanes may adversely affect reliability and operation. Corrosion and deposition data for combustion turbine materials have been obtained through dynamic testing in pressurized passages. The deposition produced by the 1900°F (1038°C) combustion gases from a simulated and a real residual oil on cooled Udimet 500 surfaces is described. Higher deposition rates for the doped fuel than for the real residual oil raised questions of whether true simulation with this approach can be achieved. Particles 4–8 μ m in dia predominated in the gas stream, with some fraction in the 0.1–12 μ m range. Deposition rates seemed to be influenced by thermophoretic delivery of small molten particles, tentatively identified as magnesium pyro and metavanadates and free vanadium pentoxide, which may act to bond the larger, solid particles arriving by inertial impaction to turbine surfaces. Estimated maintenance intervals for current utility turbines operating with washed and treated residual oil agreed well with field experience.

Improved Mayr Model of Electrical Arc Furnace to Analyse Harmonic

2011 ◽  
Vol 110-116 ◽  
pp. 1762-1766
Author(s):  
A.M. Zare Zadeh ◽  
R. Ghandehari
Keyword(s):  
Power Quality ◽  
Time Domain ◽  
Arc Furnace ◽  
Negative Effects ◽  
The Real ◽  
Electrical Arc ◽  
Real Behavior ◽  
Voltage Flicker ◽  
Harmonic Components ◽  
The Time Domain

Voltage flicker and harmonics are power quality problems which are imposed on power system by electrical arc furnace. To study furnaces and find a solution to remove the negative effects of them, it is needed to have an appropriate electrical arc furnace model. Several methods in time and frequency domain have been presented. One of the time domain methods is Mayr model which has two problems. Firstly, it shows the harmonic components more than the real values. Secondly, it does not involve voltage flicker phenomenon. In this article with the comparison of harmonic components of Mayr model and measured values of arc furnace, an improved Mayr model is introduced. In the presented model, the problems of Mayr model are removed and it shows the real behavior of arc furnace

Combustion Turbine Deposition Observations From Residual and Simulated Residual Oil Studies

1983 ◽  
Vol 105 (1) ◽  
pp. 88-96 ◽  
Author(s):  
G. A. Whitlow ◽  
S. Y. Lee ◽  
P. R. Mulik ◽  
R. A. Wenglarz ◽  
T. P. Sherlock ◽  
...  
Keyword(s):  
Vanadium Pentoxide ◽  
Field Experience ◽  
Dynamic Testing ◽  
Solid Particles ◽  
Residual Oil ◽  
Deposition Rates ◽  
Inertial Impaction ◽  
The Real ◽  
Combustion Gases ◽  
Current Utility

Burning residual oil in utility combustion turbines and the consequent deposition on blades and vanes may adversely affect reliability and operation. Corrosion and deposition data for combustion turbine materials have been obtained through dynamic testing in pressurized passages. The deposition produced by the 1900°F (1038°C) combustion gases from a simulated and a real residual oil on cooled Udimet 500 surfaces is described. Higher deposition rates for the doped fuel than for the real residual oil raised questions of whether true simulation with this approach can be achieved. Particles 4–8 μm in diameter predominated in the gas stream, with some fraction in the 0.1–12 μm range. Deposition rates seemed to be influenced by thermophoretic delivery of small molten particles, tentatively identified as magnesium pyro and metavanadates and free vanadium pentoxide, which may act to bond the larger solid particles arriving by inertial impaction to turbine surfaces. Estimated maintenance intervals for current utility turbines operating with washed and treated residual oil agreed well with field experience.

A viscoelastic Timoshenko shaft finite element for dynamic analysis of rotors

2016 ◽  
Vol 24 (11) ◽  
pp. 2180-2200 ◽  
Author(s):  
Smitadhi Ganguly ◽  
A Nandi ◽  
S Neogy
Keyword(s):  
Finite Element ◽  
Elastic Strain ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Viscoelastic Behavior ◽  
Beam Shape ◽  
Unit Step ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
The Time Domain

A new shaft element is proposed for viscoelastic rotors in a spinning frame considering the shear deformation in addition to bending deformation. The Maxwell–Wiechert model is considered here to replicate linear viscoelastic behavior. This model considers additional internal damping displacement variables between elastic and viscous elements and the stress depends not only on the elastic strain and elastic strain rate, but also on additional strains and their rates corresponding to the damping variables. The present work assumes that these additional strains can be derived from continuous fictitious displacement variables, which in turn are interpolated from their nodal values using the Timoshenko beam shape functions. Therefore, in addition to the standard degrees of freedom for a three-dimensional shaft, extra degrees of freedom are defined at the nodes. The finite element matrices are assembled in state space. The time domain equations are then used for stability analysis and computation of response to a unit step load and an unbalance.

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