scholarly journals Estimation of the amplitude of dynamic stresses on the contour of the well in the mountain range by the parameters of bench tests of hydraulic oscillators

2019 ◽  
Vol 109 ◽  
pp. 00106
Author(s):  
Oleh Usov
Keyword(s):  
Natural Frequencies ◽  
Pulse Generator ◽  
Bench Test ◽  
Mountain Range ◽  
Dynamic Stresses ◽  
Bench Tests ◽  
Tangential Stresses ◽  
Measuring Bench ◽  
Hydraulic Pulse

Presented a method for calculating the dynamic tangential stresses around the wellbore, at the time of its treatment by the hydraulic pulse generator, by the values of its characteristics, obtained at the bench test, and the frequency coefficients of influence. Criteria are formulated for selecting the natural frequencies of the measuring sensors that ensure the coincidence of voltages in the array and on the measuring bench.

scholarly journals Similarity Analysis between Scale Model and Prototype of Large Vibrating Screen

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Zerong Zhang ◽  
Yongyan Wang ◽  
Zhimin Fan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Similarity Theory ◽  
Similarity Criteria ◽  
Scale Model ◽  
Mode Shapes ◽  
Dynamic Stresses ◽  
Operating Condition ◽  
Vibrating Screen ◽  
Scale Down

In order to predict the physical characteristics of the large vibrating screen from its scale-down model, the similarity ratios of the frequency response functions, mode shapes, and dynamic stresses between the prototype and the scale model screen are built according to the similarity theory. The natural frequencies and modal shapes are extracted from the frequency response function by means of modal tests, in which the relative error of the natural frequencies is less than 9% and the modal shapes are consistent between the prototype and the model. The operating condition parameters including dynamic stress, displacement, velocity, and acceleration were also measured and conform to the similarity criteria. The results show that the inherent and operating condition parameters of the large vibrating screen can be obtained from the scale-down model conveniently, which provides an effective method for structural optimization and substructure coupling analysis of the large vibrating screen.

A GEOMETRICAL SURFACE TEXTURE STUDY OF CYCLOID DRIVE DISCS AFTER BENCH TESTS

Tribologia ◽  
2021 ◽  
Vol 297 (3) ◽  
pp. 27-33
Author(s):  
Krzysztof Olejarczyk ◽  
Marek Kalbarczyk
Keyword(s):  
Wear Resistance ◽  
Working Conditions ◽  
Surface Texture ◽  
Potential Application ◽  
Bench Test ◽  
Roughness Parameters ◽  
Bench Tests ◽  
Lubrication Film ◽  
Test Parameters ◽  
Before And After

The article presents the results of a geometrical surface texture study of cycloid drive discs after bench tests. For this purpose, the working surfaces, such as peak and valley areas of the epicycloid and the holes inner surfaces of both discs, were investigated using contact profilometry. From each surface, a transverse profiles were extracted, before and after 50 cycles of bench test. The discs and the profiles were examined for signs of wear and roughness changes. For each profile, the Ra and Rz roughness parameters were determined. On the base of the obtained profiles and the values of roughness parameters, it can be stated that the assumed test parameters provide stable working conditions, with an uninterrupted lubrication film, which results in practically negligible and unmeasurable wear. Taking into account the operating specification of a helicopter winch as an example of potential application of the presented cycloidal drive, the developed solution fulfils the requirements concerning wear resistance.

scholarly journals Correlation between Numerical and Experimental Structural Resistance of a Safety Relevant Aluminum Automotive Component

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 949
Author(s):  
Cecchel ◽  
Ferrario ◽  
Mega ◽  
Cornacchia
Keyword(s):  
Correlation Method ◽  
Field Measurements ◽  
Real Data ◽  
Bench Test ◽  
Careful Evaluation ◽  
Element Analysis ◽  
Bench Tests ◽  
Operating Environments ◽  
Structural Resistance

Accurate implementation of weight reduction for the development of innovative safety-relevant components, such as suspension assemblies, requires a careful evaluation of the structural resistance. The validation of these critical parts usually employs Finite Element Analysis (FEA) during the design phase and laboratory tests on prototypes during later stages. However, the results of these established methods have rarely been numerically compared. The present paper introduces a method for comparing FEA and testing, based on the elaboration of micro-strains acquired with strain gauges positioned in specific regions. The model was applied to the real case study of an innovative lightweight cross beam. FEA simulations and bench tests under different conditions that were representative of the operating environments were carried out. Two different relevant configurations of fatigue bench tests were considered. Then, the data obtained from testing were numerically elaborated in order to compare them with the analytical results. Real data from in-field measurements were used. The cross beam endured at the elevate mission loads reproduced at the bench test. The FEA and testing results were aligned. The correlation method was proven to be reliable, since it made it possible not only to numerically evaluate the testing output, but also to validate the calculation tools, and it could be extended to similar applications in future.

The Dynamic Influence of Crystal Orientation on a Second Generation Single Crystal Material for Turbine Buckets

2009 ◽  
Author(s):  
Marco Manetti ◽  
Iacopo Giovannetti ◽  
Nicola Pieroni ◽  
Horia Horculescu ◽  
Guido Peano ◽  
...  
Keyword(s):  
Single Crystal ◽  
Gas Turbine ◽  
High Cycle Fatigue ◽  
Natural Frequencies ◽  
Turbine Engines ◽  
Vibration Modes ◽  
Gas Turbine Engines ◽  
Directionally Solidified ◽  
Dynamic Stresses ◽  
High Frequency Vibrations

High cycle fatigue is a factor that influence gas turbine buckets lifetime and it’s due to high frequency vibrations during service. Rotation and fluid flow around the blades cause static and dynamic stresses on the buckets row. For this reason the natural frequencies and HCF resistance evaluation are fundamental in the design phase of gas turbine engines in order to avoid resonance problems during service. Single crystal and directionally solidified superalloys shows anisotropic material properties, in particular single crystal can be modeled as orthotropic material in lattice directions for FEM simulations purposes. In this paper the influence of the lattice growth orientation, identified by two angles, on the natural frequencies of first stage bucket has been investigated. Six-sigma analysis has been performed in order to obtain a transfer function between lattice orientation and bucket vibration. The Design of Experiment (DoE) has been performed using FEA modal results on ten different vibration modes. The results obtained by FEA are verified by an experimental test on the real Heavy Duty MS5002 buckets.

scholarly journals Track loading on Russian Railways under modern maintenance conditions

2019 ◽  
Vol 135 ◽  
pp. 02002
Author(s):  
Victor Kochergin ◽  
Igor Maksimov ◽  
Victor Pevzner ◽  
Evgeniya Polunina
Keyword(s):  
Point Contact ◽  
Field Tests ◽  
Test Methods ◽  
Test Method ◽  
Rolling Stock ◽  
Bench Test ◽  
Contact Loading ◽  
Static Tests ◽  
Bench Tests ◽  
Wide Range

Rail fasteners loading and its influence on the track deformability under modern maintenance conditions with increased cars axle loads is observed. The difference between oneand two-point wheelrail contact loading scheme is shown. The authors present the analysis of domestic and foreign methods of pads bench tests and show the necessity of carrying out tests imitating real (two-point contact) loading of pads. The bench test method for researching fastener loading and pad strain characteristics in a wide range of vertical and lateral loads under two-point contact scheme based on a number of field tests is presented. The results of static tests and following dynamic ones with cycling loading, which were carried out on a two-sleepers bench, are observed. Bench tests carried out by VNIIZHT and the analysis of the cyclic test methods showed the importance of fasteners tests with a real loading simulation making it possible to explain the causes of track gauge widening and decrease of track inclination, which considerably influences track stability and wear of the track and rolling stock.

Numerical Analysis of Crack Propagation and Life Estimation of Curtis Stage Blade of a Steam Turbine

2007 ◽  
Author(s):  
J. A. Rodri´guez ◽  
J. Kubiak ◽  
J. C. Garci´a ◽  
Jose´ A. Segura ◽  
F. Sierra ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Finite Element ◽  
Numerical Analysis ◽  
Crack Propagation ◽  
Forced Vibration ◽  
Natural Frequencies ◽  
Element Model ◽  
Forced Vibrations ◽  
Dynamic Stresses ◽  
Life Estimation

During the operation of a turbomachine the parts most exposed to the alternative forces are the blades. The Curtis stage blades are then subjected to high alternative loads which may cause forced vibrations and these may fracture and fatigue the blades, affecting the integrity of the machine and causing its consequential shut down. In this paper the numerical analysis of crack propagation in Curtis stage blade subject to forced vibrations is presented. A finite element model of the Curtis stage blade was constructed. The natural frequencies, the steady and dynamic stresses were calculated according to life estimation. The stresses due to forced vibration were estimated using the alternative forces based in computed numerical fluid dynamics from a previous study.

Identification of Eigenmodes and Determination of the Dynamical Behaviour of Open Impellers

2012 ◽  
Author(s):  
Yves Bidaut ◽  
Urs Baumann
Keyword(s):  
Dynamic Behaviour ◽  
Natural Frequencies ◽  
Life Time ◽  
Dynamical Behaviour ◽  
Strain Gauges ◽  
Laser Vibrometer ◽  
Fe Model ◽  
Impeller Blade ◽  
Dynamic Stresses ◽  
Simplified Approach

Whenever an open bladed impeller (without shroud) is implemented in a centrifugal compressor a key issue regarding the reliability of the compressor concerns the dynamical behaviour of this impeller. Due to the absence of the shroud this impeller can be operated at high tip speeds, hence allowing for higher volume flow. However the impeller reacts very sensitive to excitations leading to large blade vibrations with potential considerable dynamic stresses. In order to avoid resonance caused by fluctuating pressure distributions due to rotor-stator interactions special attention must be paid to the natural frequencies of the impeller which shall be determined with the highest accuracy possible. Therefore this paper focuses on the identification of the natural frequencies of the impeller first. To validate the finite-element (FE) model extensive measurements of the natural frequencies are performed at standstill. Especially the set-up and results obtained with the Shaker-Laser vibrometer-tests are described in detail and compared to other measurement methods such as the Laser-Scaning-Vibrometry (LSV) and strain gauges. Furthermore the prediction of the dynamic behaviour of the impeller is of considerable importance in the design of turbo compressors. For this purpose comprehensive measurements of the dynamic stress are carried out on the author’s company’s test rig. The paper describes the test arrangement including numerous strain gauges installed in different positions of the blades. The last part of this paper describes a simplified approach for the evaluation of the dynamic stresses in the impeller blade. A substantial list of comprehensive lectures about coupled CFD–structural analysis to determine the dynamic behaviour of impeller blades is available. However, despite of considerable improvement in software and calculation methods in the last years, such analyses are still expensive and require very large capacities. The presented alternative calculation method is based on a harmonic analysis which is calibrated to the measurements and is the base for a further estimation of the life time of the impeller.

Introduction to Cell Membranes at Molecular Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 497-502
Author(s):  
R.J. Barrnett
Keyword(s):  
Cell Membranes ◽  
International Federation ◽  
Mountain Range ◽  
Cellular Membranes ◽  
Short History ◽  
Biological Organization ◽  
Macromolecular Assemblies ◽  
The Past

This subject, is like observing the panorama of a mountain range, magnificent towering peaks, but it doesn't take much duration of observation to recognize that they are still in the process of formation. The mountains consist of approaches, materials and methods and the rocky substance of information has accumulated to such a degree that I find myself concentrating on the foothills in the foreground in order to keep up with the advance; the edifices behind form a wonderous, substantive background. It's a short history for such an accumulation and much of it has been moved by the members of the societies that make up this International Federation. My panel of speakers are here to provide what we hope is an interesting scientific fare, based on the fact that there is a continuum of biological organization from biochemical molecules through macromolecular assemblies and cellular membranes to the cell itself. Indeed, this fact explains the whole range of towering peaks that have emerged progressively during the past 25 years.

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