scholarly journals Experimental study of vibrations of a steel beam in order to determine the damping coefficients of the material based on the idea of the limit transition using a laser vibrometer

2021 ◽  
pp. 117-122
Author(s):  
Н.А. Тарануха ◽  
Ко.Ко. Мин
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Experimental Studies ◽  
Frequency Characteristics ◽  
Steel Beam ◽  
Laser Vibrometer ◽  
Practical Application ◽  
Microsoft Excel ◽  
Limit Transition ◽  
Damping Coefficients

Данная работа посвящена экспериментальным исследованиям консольной балки, разработке методики проведения измерений колебаний в среде на основе измерений в воздухе и жидкости (воде). Измерение амплитудно-частотных характеристик производится с помощью лазерного виброметра: “Polytec High Speed Laser Vibrometer HSV2001, Polytec GmbH, Germany”. Для снятия показаний в экспериментах ис-пользовалась программа «Рolytec vibrometer software» (Polytec High Speed Laser Vibrometer HSV2001, Polytec GmbH, Germany). Обработка экспериментальных данных и построение графиков проводились с помощью программы «Microsoft Excel» с включением в нее фрагментов собственного программного обеспечения. Главной конечной целью является определение коэффициентов демпфирования материала колеблющейся конструкции. При этом используется идея предельного перехода. Методика является оригинальной. Ее оригинальность заключается в использовании новой идеи предельного перехода и выполнении экспериментов на базе виброметра (Polytec High Speed Laser Vibrometer HSV2001). Полученные на основе экспериментальных исследований результаты также являются оригинальными. Методика создана для практического применения и позволяет определять амплитудно-частотные характеристики систем, колеблющихся в различных жидкостях и состоящих из различных материалов. This paper is devoted to experimental studies of the cantilever beam, the development of methods for measuring vibrations in the medium based on measurements in air and liquid (water). The amplitude-frequency characteristics are measured using a laser vibrometer: “Polytec High Speed Laser Vibrometer HSV2001, Polytec GmbH, Germany”. To take readings in the experiments, the program "Polytec vibrometer software" (Polytec High Speed Laser Vibrometer HSV2001, Polytec GmbH, Germany) was used. The processing of experimental data and the construction of graphs were carried out using the Microsoft Excel program with the inclusion of fragments of its own software. The main ultimate goal is to determine the damping coefficients of the material of the oscillating structure. In this case, the idea of a limit transition is used. The technique is original. Its originality lies in the use of a new idea of the limit transition and performing experiments based on a vibrometer (Polytec High Speed Laser Vibrometer HSV2001). The results obtained on the basis of experimental studies are also original. The method is designed for practical application and allows to determine the amplitude-frequency characteristics of systems that oscillate in different fluids and consist of different materials.

Measurement of Physical and Mechanical Properties of High-Speed Heated Casting Cores

2015 ◽  
Vol 729 ◽  
pp. 114-118
Author(s):  
Ivan Nikolaevich Erdakov ◽  
Viktor Vladimirovich Novokreshchenov ◽  
Vladimir Michaylovich Tkachev ◽  
Ranil Danillovich Gabbasov
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
High Speed ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Deformation Model

The paper presents the results of experimental studies of physical and mechanical properties of casting cores (-set process using Carbectis binder) high-speed heated with subsequent destruction. Based on experimental data, such parameters of deformation model of a core are obtained which permit to calculate the values of hindered shrinkage of AK7Ch alloy with the accuracy of 1.5 %.

scholarly journals Advantages of applying the mixture when guniting on vertical surfaces of building envelope

2021 ◽  
Vol 258 ◽  
pp. 09049
Author(s):  
Anatoliy Abramenko ◽  
Elena Gorbaneva ◽  
Aleksey Semyenov ◽  
Andrey Mishchenko ◽  
Dmitriy Loboda
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Classical Method ◽  
Experimental Studies ◽  
Vertical Surface ◽  
Building Envelope ◽  
Practical Application ◽  
Technological Parameters ◽  
Number Of Factors ◽  
Sufficient Degree

Having studied the technological modes of applying the mixture by the guniting method on hard unyielding surfaces, we can conclude that the technology for applying building mixtures is formed depending on changes in a number of factors (including the strength characteristics and the rebound of the mixture from the vertical surface). Experimental study of the influence of the technological parameters of application on the efficiency of guniting with the classical method and application using a nozzle for vortex application allows us to visually detect the zones of rational application of this technology. Based on the experimental data, we carried out an analysis of the influence of the technological parameters of applying the mixture on the criterion indicators. For this, we investigated various methods [8, 9], processed the results and revealed dependencies, discovered unknown aspects of gunning with the use of a nozzle for vortex application of a construction mixture. The assessment showed a sufficient degree of coincidence of theoretical and experimental studies and the possibility of their practical application, on the basis of which we can conclude about the efficiency of the nozzle for the vortex application of the building mixture.

scholarly journals DEVELOPMENT OF CALCULATION METHOD FOR TENSILE STRENGTH OF ROCK SAMPLES UNDER COMPRESSION

2020 ◽  
Vol 4 (53) ◽  
pp. 85-91
Author(s):  
Leonid M. VASIL’EV ◽  
◽  
Michael A. ZHURAVKOV ◽  
Dmitriy L. VASIL’EV ◽  
Mykola G. MALICH ◽  
...  
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Relative Error ◽  
Experimental Studies ◽  
Vertical Component ◽  
Contact Friction ◽  
Practical Application ◽  
Angle Of Internal Friction ◽  
Rock Samples ◽  
Characteristic Values

The paper describes a procedure for improving the approach to determining the ultimate strength of rock samples, the basic method is L. Prandtl’s method. In earlier works of the authors of this paper, the L. Prandtl’s method was improved in relation to rocks, using a general algebraic equation for calculating horizontal normal stresses depending on the vertical component and mechanical characteristics of the rock. Here, the authors reject the assumption that the tangent contact stresses resulting from L. Prandtl's solution do not depend on the abscissa x and on the variable vertical stresses, in contrast to the well-known Coulomb–Amonton law, according to which the tangent stresses are directly proportional to the vertical pressure. The regularities of contact normal and tangential stresses distribution at failure of prismatic samples are clarified. As result, the method was developed for calculating the tensile strength of samples with three characteristic values of mechanical properties: kп, yield strength of material in shear; ρ, angle of internal friction; fс, coefficient of contact friction. These characteristics can be established experimentally by simple experimental studies. The proposed approach is effective for constructing ultimate curves and diagrams of “stress — longitudinal strain” of rocks in the case of contact friction. A comparative evaluation is given for the proposed method for calculating the tensile strength of samples during their destruction with experimental data. Comparison of the calculated tensile strength with experimental data shows that the relative error of calculations according to the proposed method is significantly lower than the relative error of calculations performed using the E. Unksov’s method. The proposed method can be recommended for practical application.

scholarly journals Explosive generators of high-speed preformed fragment flows

2018 ◽  
pp. 23-29
Author(s):  
K. A. Zaplohova ◽  
G. S. Isaev ◽  
A. E. Kurepin ◽  
E. V. Sidorova
Keyword(s):  
Experimental Data ◽  
Initial Data ◽  
Satisfactory Agreement ◽  
High Speed ◽  
Experimental Studies ◽  
Three Dimensional ◽  
The Creation ◽  
Target Design ◽  
Research Show

When assessing the effectiveness of ammunition designed to destroy various aerodynamic and ballistic targets, as the initial data on the vulnerability of the destruction objective, we use indicators obtained during experimental studies of the processes of fragments and fragment flow collision with various fragments of the target design. The results depend not only on the speed and mass of individual fragments, but also on their shape and location in the flow. The paper gives the results of the testing of an explosive thrower which provides the creation of a high-speed, i.e. ~5 km/s, flow of fragments of a given shape. Findings of research show satisfactory agreement between the results of calculations carried out in two- and three-dimensional statements with experimental data on high-speed throwing of a group of compact, parallelepiped, steel preformed fragments weighing 20 g each

AN EXPERIMENTAL RESEARCH OF A SPILLWAY WITH A WIDE THRESHOLD OF A RESERVE WATER OUTLET

2015 ◽  
Vol 5 (3) ◽  
pp. 73-81
Author(s):  
Yuriy Mikhaylovich KOSICHENKO ◽  
Evgeniy Dmitrievich MIKHAYLOV ◽  
Oleg Andreevich BAEV
Keyword(s):  
Experimental Data ◽  
Relative Error ◽  
Experimental Research ◽  
Structural Engineering ◽  
Discharge Coefficient ◽  
Experimental Studies ◽  
Experimental Results ◽  
Empirical Dependence ◽  
Microsoft Excel ◽  
Water Leakage

The aim of this paper is to introduce results of an experimental research of a spillway with a wide threshold. To identify this spillway main characteristics the authors use traditional methods of hydraulic calculations. The paper presents experimental data of a spillway with a wide threshold at δ/H>8...10 which were obtained on a hydraulic tray in the laboratory of hydro technical structures and structural engineering of Don State Agrarian University named after A.K. Kortunov. The research demonstrates basic dependences for the event of water leakage through a spillway with a wide threshold for a fl at stress problem. The obtained values of discharge coefficient for a spillway with a wide threshold at δ/H>8...10 are within the limits of 0,303≤mспр≤0,305 with a relative error 0.0242-0.0076%. Taking in account experimental studies and using a well-known formula by H.А. Tibara the authors specified the dependence for calculating discharge coefficient for a spillway with a wide threshold. The experimental results were mathematically processed by Microsoft Excel, and a new empirical dependence m=f(P/H) was introduced.

Experimental Studies of Bifurcations Leading to Chaos in a Laboratory Scale Thermoacoustic System

2011 ◽  
Author(s):  
Lipika Kabiraj ◽  
R. I. Sujith ◽  
Pankaj Wahi
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Nonlinear Oscillations ◽  
Experimental Studies ◽  
Nonlinear Time Series Analysis ◽  
Bifurcation Parameter ◽  
Chaotic Oscillations ◽  
Chemiluminescence Intensity ◽  
Intensity Measurements ◽  
Thermoacoustic Oscillations

Bifurcation analysis is conducted on experimental data obtained from a simple setup comprising of ducted, laminar pre-mixed conical flames to investigate the features of nonlinear thermoacoustic oscillations. It is observed that as the bifurcation parameter is varied, the system undergoes series of bifurcations leading to characteristically different nonlinear oscillations. Through the application of nonlinear time series analysis on pressure and flame (CH* chemiluminescence) intensity time traces, these oscillations are characterised as periodic, aperiodic or chaotic oscillations and subsequently the nature of the obtained bifurcations is explained based on dynamical systems theory. Nonlinear interaction between the flames and the acoustic modes of the duct is clearly reflected in the high speed flame images acquired simultaneously with pressure and flame intensity measurements.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

Diagnostics of metal samples using the results of experimental and theoretical study of positively charged microparticles formed upon sample destruction

2018 ◽  
Vol 84 (10) ◽  
pp. 23-28
Author(s):  
D. A. Golentsov ◽  
A. G. Gulin ◽  
Vladimir A. Likhter ◽  
K. E. Ulybyshev
Keyword(s):  
Experimental Data ◽  
Early Stage ◽  
Experimental Studies ◽  
Material Model ◽  
Total Charge ◽  
Cross Sectional ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Order Of Magnitude ◽  
Using Data

Destruction of bodies is accompanied by formation of both large and microscopic fragments. Numerous experiments on the rupture of different samples show that those fragments carry a positive electric charge. his phenomenon is of interest from the viewpoint of its potential application to contactless diagnostics of the early stage of destruction of the elements in various technical devices. However, the lack of understanding the nature of this phenomenon restricts the possibility of its practical applications. Experimental studies were carried out using an apparatus that allowed direct measurements of the total charge of the microparticles formed upon sample rupture and determination of their size and quantity. The results of rupture tests of duralumin and electrical steel showed that the size of microparticles is several tens of microns, the particle charge per particle is on the order of 10–14 C, and their amount can be estimated as the ratio of the cross-sectional area of the sample at the point of discontinuity to the square of the microparticle size. A model of charge formation on the microparticles is developed proceeding from the experimental data and current concept of the electron gas in metals. The model makes it possible to determine the charge of the microparticle using data on the particle size and mechanical and electrical properties of the material. Model estimates of the total charge of particles show order-of-magnitude agreement with the experimental data.

scholarly journals Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3609
Author(s):  
Mykola Sysyn ◽  
Michal Przybylowicz ◽  
Olga Nabochenko ◽  
Lei Kou
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Dynamic Interaction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Monitoring Methods ◽  
Beam Dynamic ◽  
Track Geometry ◽  
Data Driven Approach ◽  
Support Conditions

The ballasted track superstructure is characterized by a relative quick deterioration of track geometry due to ballast settlements and the accumulation of sleeper voids. The track zones with the sleeper voids differ from the geometrical irregularities with increased dynamic loading, high vibration, and unfavorable ballast-bed and sleeper contact conditions. This causes the accelerated growth of the inhomogeneous settlements, resulting in maintenance-expensive local instabilities that influence transportation reliability and availability. The recent identification and evaluation of the sleeper support conditions using track-side and on-board monitoring methods can help planning prevention activities to avoid or delay the development of local instabilities such as ballast breakdown, white spots, subgrade defects, etc. The paper presents theoretical and experimental studies that are directed at the development of the methods for sleeper support identification. The distinctive features of the dynamic behavior in the void zone compared to the equivalent geometrical irregularity are identified by numeric simulation using a three-beam dynamic model, taking into account superstructure and rolling stock dynamic interaction. The spectral features in time domain in scalograms and scattergrams are analyzed. Additionally, the theoretical research enabled to determine the similarities and differences of the dynamic interaction from the viewpoint of track-side and on-board measurements. The method of experimental investigation is presented by multipoint track-side measurements of rail-dynamic displacements using high-speed video records and digital imaging correlation (DIC) methods. The method is used to collect the statistical information from different-extent voided zones and the corresponding reference zones without voids. The applied machine learning methods enable the exact recent void identification using the wavelet scattering feature extraction from track-side measurements. A case study of the method application for an on-board measurement shows the moderate results of the recent void identification as well as the potential ways of its improvement.

An investigation of effects of level density models and gamma ray strength functions on cross-section calculations for the production of 90Y, 153Sm, 169Er, 177Lu and 186Re therapeutic radioisotopes via (n,γ) reactions

2019 ◽  
Vol 108 (1) ◽  
pp. 11-17
Author(s):  
Mert Şekerci ◽  
Hasan Özdoğan ◽  
Abdullah Kaplan
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Production Cross Section ◽  
Gamma Ray ◽  
Production Cross ◽  
Level Density ◽  
Experimental Studies ◽  
Level Density Models ◽  
Strength Functions ◽  
Cancer Diseases

Abstract One of the methods used to treat different cancer diseases is the employment of therapeutic radioisotopes. Therefore, many clinical, theoretical and experimental studies are being carried out on those radioisotopes. In this study, the effects of level density models and gamma ray strength functions on the theoretical production cross-section calculations for the therapeutic radioisotopes 90Y, 153Sm, 169Er, 177Lu and 186Re in the (n,γ) route have been investigated. TALYS 1.9 code has been used by employing different level density models and gamma ray strength functions. The theoretically obtained data were compared with the experimental data taken from the literature. The results are presented graphically for better interpretation.

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