Calculation of Vibration Resistance of Chemical Reactor High-Speed Shaft Undergoing Torsional Vibrations. Part II. Defining Model Elastic-Inertial Parameters

2021 ◽  
pp. 768-779
Author(s):  
N. A. Merentsov ◽  
N. S. Sokolov-Dobrev ◽  
A. V. Persidskiy
Keyword(s):  
High Speed ◽  
Chemical Reactor ◽  
Torsional Vibrations ◽  
Vibration Resistance ◽  
Inertial Parameters

Application of Experimental Modal Analysis Method in Researching of Mechanical Structure Dynamic Characteristics

2013 ◽  
Vol 694-697 ◽  
pp. 370-373
Author(s):  
Zhang Yu ◽  
Wen Zheng Cai
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Experimental Modal Analysis ◽  
Analysis Method ◽  
Mechanical Structure ◽  
Vibration Resistance ◽  
Structural Rigidity ◽  
Structure Dynamic

With the purpose of realizing the analysis of mechanical structure dynamic characteristics and inhibit vibration and noise, combined with the analysis of a certain type of high speed sewing machines vibration characteristics, we carry on the concrete experimental modal analysis, and compare the results of the experimental modal analysis with the results of spectrum analysis. The analysis results show that the second order natural frequency of the shell is close to two octaves under the normal working speed of sewing machine and it will lead to resonance. Enhancing the structural rigidity and the natural frequency under this modal to avoid resonance frequency is the key to improve vibration resistance of the structure.

Paper 4: Opening, Carding and Spinning Preparation Machines

1966 ◽  
Vol 181 (12) ◽  
pp. 1-7
Author(s):  
H. Catling
Keyword(s):  
High Speed ◽  
Unit Length ◽  
High Amplitude ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
Periodic Disturbance ◽  
The Past ◽  
Machine Utilization ◽  
Lubrication Conditions ◽  
New Machine

There are no serious bearing problems in opening and carding machines. Except for the high-speed beaters and cylinders, occasionally-oiled plain journals were long regarded as adequate despite the fact that many of them operated under boundary lubrication conditions. Stable hydrodynamic film conditions were maintained in beater and cylinder bearings and some simple form of lubricant reservoir was usually provided. In recent years the introduction of shift working and high machine utilization factors have led to a demand for machines requiring a minimum of attention. This demand is being met by the use of prepacked, sealed ball or roller bearings at all points. Perhaps the most serious and intractable bearing problem in the whole field of textile machinery manufacture is encountered in drawframes and speedframes. For uniformity of the drawing action by which the fibres are straightened and finally attenuated to form a roving, it is necessary for all the drafting rollers to rotate perfectly smoothly. Unfortunately the loading conditions and the rotational speeds of some of the rollers are such that there is often a high liability to the occurrence of spontaneous stick–slip torsional vibrations. In other cases there is an incipient liability to stick–slip vibration and quite small gearing faults, of the appropriate frequency, are sufficient to precipitate high amplitude oscillations. At the frequencies commonly observed the non-uniformity of the drawing action introduces into the sliver or roving a periodic disturbance of a wavelength so short that it is not readily apparent in the delivery from the affected machine. Subsequent drafting, however, increases the wavelength and the ultimate yarn exhibits appreciable variations in mass per unit length and in twist distribution. As these variations are strictly periodic they form objectionable interference patterns when used as weft in either woven or knitted cloths. New machine designs and the use of new types of bearings have largely solved these problems and at the same time greatly increased operating speeds. The comber, too, has been intensively developed during the past ten years and a number of lubrication and wear problems have required attention.

Performance of Air-Lubricated Hydrodynamic Bearing Spindles for Laser Scanners

1991 ◽  
Vol 113 (3) ◽  
pp. 609-614 ◽  
Author(s):  
K. Tanaka ◽  
H. Muraki
Keyword(s):  
High Speed ◽  
High Performance ◽  
Experimental Results ◽  
Hydrodynamic Bearing ◽  
Vibration Resistance ◽  
High Speeds ◽  
Laser Printers ◽  
Laser Scanners

This paper reports on the performance of air-lubricated bearing spindles for high-speed laser scanners using newly developed bearings. Experimental results confirmed that these spindles have adequate performance including floating stability, endurance, vibration-resistance at high-speeds, and start-stop endurance for laser scanners. These spindles are already mass-produced and used in laser printers and digital color copiers, so their high performance and endurance are proven.

Torsional Vibrations of the Steam Turbine Shaft Line and Estimation of the Residual Life of Its Elements

2020 ◽  
Vol 63 (6) ◽  
pp. 91-98
Author(s):  
Vladimir Grabovskii ◽  
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Residual Life ◽  
Operating Time ◽  
Electromagnetic Transients ◽  
Torsional Vibrations ◽  
Steam Turbines ◽  
Shaft Line ◽  
Operating Modes ◽  
Design Life

A comparative quantitative assessment of the damage and residual life of the shaft line elements for differ-ent types of high-power steam turbines at the end of their design life is made by mathematical modeling. The analysis covers all elements of the shaft line: from the steam turbine Central pump to the turbine generator ex-citer. The simulated circuit includes turbo generators, transformers, gate converters, AC and DC power lines. When modeling, an approach is used from the position of proper coordinates, which provides maximum meth-odological consistency of the models of the listed devices and allows you to directly reproduce electromagnetic and mechanical transients with the determination of instantaneous values of currents, voltages, electromagnet-ic and torsional moments. To estimate damage, we used the deformation criterion for soft and hard loads in the zone of low-cycle and force criterion in the zone of multi-cycle fatigue. The influence of the number of starts and running time of a steam turbine on the damage and residual life of its shaft elements is studied. When de-termining the remaining life, in addition to starts, other abnormal operating modes of the turbo generator were taken into account during the turbine operating time: short circuits and their disconnections, unsuccessful high-speed automatic re-activation, subsynchronous resonance due to both the operation of the control system of the PPT and the automatic generator excitation regulator. The influence of attenuation of electromagnetic transients in the generator and damping of torsional vibrations on the degree of reduction of the residual life of the shaft elements is analyzed. The results obtained can be used for a comprehensive solution of the issue of further operation of steam turbines that have spent their design life.

scholarly journals Big Data Accumulation of L-Shape Extruded Alloys for Interior Parts for High-Speed Trains

2019 ◽  
Vol 8 (2S6) ◽  
pp. 143-148
Keyword(s):  
Tensile Properties ◽  
High Speed ◽  
Process Conditions ◽  
Complicated Shape ◽  
Casting Method ◽  
High Speed Railway ◽  
Vibration Resistance ◽  
Heat Treated ◽  
Cast Product ◽  
High Speed Trains

L-Shape extruded alloys were manufactured by adopting aluminum alloy as the candidate lightweight alloy to be used for interior and exterior materials of high-speed trains. The cast product was extruded using the air slip (AS) casting method and the direct casting (DC) method. The product was again heat-treated with T5 or T6 tempering. According to literature research, the candidate alloys were selected as 6063, 6N01, 6061, 6060, 6005 and 5083 alloys. These alloys were extruded after casting and heat-treated and their properties such as the hardness, microstructure and tensile properties were evaluated. The hardness, microstructure and tensile properties of the selected 6063, 6N01, 6061, 6005 and 5083 aluminum alloys in the present study are similar to those of external materials made by Alcan, Canada. Mechanical properties of the extruded materials were comparable to those of external materials (manufactured by Canada, Alcan). The hardness, microstructure, and extrusion characteristics of AA6063, AA6N01, AA6061, AA6005, AA6060 and AA5083 alloys selected in the present study through literature review are similar to those of external materials (Canada, Alcan). By performing extrusion, under the conditions of high-speed railway, the process conditions for manufacturing extruded materials with complicated shape to meet the requirements of vibration resistance and airtightness have been established. Therefore, it was proved to be sufficient as the interior and exterior materials of high-speed train.

Recent Achievements and Future Challenges in Nanoscience and Nanotechnology

2020 ◽  
Vol 22 (4) ◽  
pp. 241
Author(s):  
Z.A. Mansurov
Keyword(s):  
High Speed ◽  
Soot Formation ◽  
Chemical Reactor ◽  
Synthesis Methods ◽  
External Energy ◽  
Synthesis Conditions ◽  
Nanosized Materials ◽  
Future Challenges ◽  
Nanocarbon Materials ◽  
Nanomaterials Synthesis

The article presents the investigation results of the formation and synthesis of nanosized materials which were obtained at the Institute of Combustion Problems, many works have been brought to practical use. Investigations of low-temperature soot formation become the basis of nanomaterial synthesis methods, developed at the Institute for Combustion Problems since 1985. Flame can be considered as a chemical reactor to produce target products. The main feature of the processes based on technological combustion is that the target product is formed as a result of the combustion reaction, occurring spontaneously at high temperatures with a high speed without consuming external energy, i.e. due to its own heat. With the development of nanotechnology, new challenges have emerged in the synthesis of nanomaterials under combustion synthesis conditions. Below is a list of works on nanomaterials synthesis carried out at the Institute: complete scheme of soot formation; energy intensive nanocarbon materials; development and study of perovskite photocatalysts for hydrogen evolution; obtaining carbon fibers by the method of electrospinning; obtaining of biologically soluble membranes based on polymeric nanofibres and hydroxyapatite of calcium; synthesis of nanocarbon sorbents for purification of water from heavy metal ions.

scholarly journals The Analysis Of The Vibratory Movement Of The Gun Barrel And Its Influence On The Firing Accuracy

2015 ◽  
Vol 21 (3) ◽  
pp. 883-887 ◽  
Author(s):  
Alin-Constantin Sava ◽  
Ioan-Liviu Piticari ◽  
Diana-Georgeta Nistoran ◽  
Cristian-Emil Moldoveanu
Keyword(s):  
High Speed ◽  
Firing Process ◽  
Torsional Vibrations ◽  
Bending Vibrations ◽  
Modern Equipment ◽  
Gun Barrel ◽  
Flexural Vibrations

Abstract It is known that the forces and shocks that occur during the firing process of a firearm induce vibrations to the barrel of the weapon and to the weapon as a whole. There are flexural, longitudinal, radial and torsional vibrations. The most important ones are considered to be the flexural or bending vibrations, especially the ones recorded in the muzzle section. This paper presents a method of recording the flexural vibrations of the barrel in the muzzle section of a 5,56mm automatic rifle and the influence of muzzle devices, using modern equipment (high speed cameras) and dedicated software.

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