CALCULATION OF THE CHARACTERISTICS OF GASOSTATIC BEARINGS

2020 ◽  
Author(s):  
Дмитрий Вадимович Симаков ◽  
Владимир Павлович Легаев
Keyword(s):  
Spindle Assembly ◽  
Gas Pressure ◽  
Dynamic Tests ◽  
Static Stiffness ◽  
Gas Layer

Одной из важнейших характеристик задачи моделирования поведения шпиндельного узла является статическое давление газа в зазоре. Испытание газового слоя на статическую жесткость позволяет судить о качестве проектируемого ШУ и в некоторой степени о характере его поведения при динамических испытаниях. Таким образом, характеристика статической жесткости газового слоя выступает в качестве первого критерия работоспособности. One of the most important characteristics of the problem of modeling the behavior of the spindle assembly is the static gas pressure in the gap. Testing the gas layer for static stiffness makes it possible to judge the quality of the projected control box and, to some extent, about the nature of its behavior during dynamic tests. Thus, the characteristic of the static stiffness of the gas layer acts as the first criterion for performance.

Experimental Study on Mechanical Characteristics of Knitted-Dapped Metal Rubber

2013 ◽  
Vol 820 ◽  
pp. 67-70
Author(s):  
Tuo Li ◽  
Hong Bai Bai ◽  
Chun Hong Lu
Keyword(s):  
Experimental Study ◽  
Dynamic Characteristics ◽  
Mechanical Characteristics ◽  
Dynamic Tests ◽  
Static Stiffness ◽  
Static Tests ◽  
Metal Rubber ◽  
Low Stiffness

Knitted-dapped metal rubber was developed to solve problems of metal rubber with low stiffness and test samples with different sizes were manufactured. Static tests and dynamic tests were carried out to study influences of density and thickness on the static stiffness and influences of frequency, amplitude and preload on dynamic characteristics. Results show that static stiffness rises when density or thickness increases. Frequency has little influence on dynamic characteristics. Knitted-dapped metal rubber will have smaller stiffness and better characteristics of damping, if amplitude increases; if preload increases, energy consumed in the vibration will be more.

Effect of Isostatic GAS Pressure on Optical Quality of MgAl2O4 Spinel

1991 ◽  
Vol 251 ◽  
Author(s):  
S.E. Hsu ◽  
C.T. Wang ◽  
D.S. Tsai ◽  
S.J. Yang
Keyword(s):  
Applied Pressure ◽  
Xrd Analysis ◽  
Optical Quality ◽  
Gas Pressure ◽  
Pressure Treatment ◽  
Before And After ◽  
Diffraction Peaks ◽  
Bimodal Grain Size ◽  
Hip Process

ABSTRACTOptical transparent MgAl2O4 spinel is obtained by processing with high gas pressure to eliminate or reduce the residual pores. Both hot–pressed and sintered specimens are post–treated by the high argon hipping process here. The densities of all the specimens before hipping are over 99% theoretical density. In the high gas pressure process, the pressure ranges from 2000 to 30000psi at 1500°C for 2hrs. The transmittance from visible to IR are measured before and after gas pressure treatment. The transparency from visible to IR increases significantly with the HIP process. When applied pressure less than 6000psi, bulk density is proportional to the logarithm of the pressure and the logarithm of the absorption coefficient is proportional to the porosity. Bimodal grain–size distribution exists in the sintered and hipped specimens but is not observed in the uniaxial–hot–pressed–only samples. XRD analysis indicates the width of the diffraction peaks in the HIP specimens is less than that in UAHP specimens. The result illustrates the HIP process improves the spinel crystallinity.

The dependence of the crystalline quality of C60 films on helium gas pressure

1997 ◽  
Vol 31 (3-6) ◽  
pp. 297-301 ◽  
Author(s):  
Guobin Ma ◽  
Yinghu Yang ◽  
Guanghua Chen
Keyword(s):  
Gas Pressure ◽  
Crystalline Quality ◽  
Helium Gas ◽  
C60 Films

scholarly journals Study on the Stiffness, Longevity and Reliability of the Spindle Unit of Eclipse 300 CNC Lathe with Different External Load

2021 ◽  
Vol 31.2 (149) ◽  
pp. 58-64
Keyword(s):  
Machine Tools ◽  
Spindle Assembly ◽  
Machining Accuracy ◽  
Initial Stiffness ◽  
Spindle Unit ◽  
Cnc Lathe ◽  
The Relationship ◽  
External Loads ◽  
Remaining Time

The stiffness of the spindle assembly of machine tools in general and also CNC machines in particular is an important criteria to evaluate the quality of machining. The initial stiffness of the spindle assembly is due to pre-load. During operating, the spindle assembly is wear under the influence of external loads including cutting force and speed. It reduces the stiffness of the spindle assembly, as well as decreasing machining accuracy. This study presents the results of various stiffness of the spindle assembly under external loads in laboratory conditions. Based on the relationship between the stiffness and the amount of axial wear of the spindle assembly according to the working time, as well as the permissible stiffness limit to predict remaining time, reliability and time of adjusting the pre-load to maintain stability and machining accuracy.

scholarly journals Double Glow Plasma Surface Metallurgy Technology Fabricated Fe-Al-Cr Coatings with Excellent Corrosion Resistance

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 575
Author(s):  
Xixi Luo ◽  
Jing Cao ◽  
Guanghui Meng ◽  
Fangli Yu ◽  
Qiong Jiang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Gas Pressure ◽  
Sample Temperature ◽  
304 Stainless Steel ◽  
Plasma Surface ◽  
Excellent Corrosion Resistance ◽  
Q235 Carbon Steel ◽  
Glow Plasma ◽  
Cr Coating

Double glow plasma surface metallurgy (DGPSM) technology was applied to obtain a Fe-Al-Cr coating on the surface of Q235 carbon steel. The influence of the sample temperature, gas pressure, the distance between the substrate, and the source electrode on the quality of the obtained Fe-Al-Cr coatings was systematically investigated. The results showed that the parameters for DGPSM have a significant effect on the uniformity, particle size, compactness, and thickness of the coating. Under the optimized parameters (sample temperature: 800 °C, gas pressure: 35 Pa, and electrode distance: 15 mm), the obtained Fe-Al-Cr coating contains Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) solid solution, Cr23C6, and α-Fe(Al), exhibiting excellent corrosion resistance in a 0.5 mol/L H2SO4 solution, which is even better than that of the 304 stainless steel.

Studies on correlation between the quality of GaAs LEC crystals and the inert gas pressure

1996 ◽  
Vol 158 (4) ◽  
pp. 409-417 ◽  
Author(s):  
M. Seifert ◽  
M. Neubert ◽  
W. Ulrici ◽  
B. Wiedemann ◽  
J. Donecker ◽  
...  
Keyword(s):  
Gas Pressure ◽  
Inert Gas

Determination of the Fatigue Resistance of Rubber Parts under Cyclic Shear Stress in Relation to Their Shape and Energy

1955 ◽  
Vol 28 (4) ◽  
pp. 1044-1053 ◽  
Author(s):  
Hermann Roelig ◽  
Guido Fromandi
Keyword(s):  
Vibration Isolation ◽  
Compression Modulus ◽  
Dynamic Tests ◽  
Shore Hardness ◽  
Cyclic Shear ◽  
Spring Suspension ◽  
Exact Design ◽  
Metal Bonds

Abstract Rubber is used far less frequently in tension than in compression for spring suspensions and vibration isolation. But for particularly soft springs, it is used in shear. For example, the compression modulus (at a deformation of 10 per cent of the height of the specimen) of a rubber cylinder 25 mm. in diameter and 25 mm. high, of 60° Shore hardness, may be 45 kg. per sq. cm., while its shearing modulus is only 7 kg. per sq. cm. Thus one may obtain a 6.5 times softer spring suspension by a shear mounting for the same volume of rubber. The use of rubber shear suspensions is facilitated by rubber-metal bonds, the quality of which today can be safely controlled technically in rubber factories. Thus we find shear suspensions in rubber-cushioned railway cars and automobile and aircraft construction. The exact design of such spring suspensions still is handicapped by lack of precise data on their fatigue strength, which can be obtained from dynamic tests. Such information would also facilitate the study of new elastomers and their comparison with those currently in use.

Three-dimensional viscoelastic numerical analysis of the effects of gas flow on L-profiled polymers in gas-assisted coextrusion

2018 ◽  
Vol 38 (5) ◽  
pp. 503-512 ◽  
Author(s):  
Xiaozhen Deng ◽  
Hesheng Liu
Keyword(s):  
Layer Thickness ◽  
Flow Rate ◽  
Gas Flow ◽  
Three Dimensional ◽  
Gas Pressure ◽  
Melt Flow ◽  
Flow Zone ◽  
Melt Flow Rate ◽  
Gas Layer ◽  
The Relationship

AbstractIn this study, polymer gas-assisted coextrusion experiments were performed. The influence of a traditional coextrusion flow zone on the gas groove and the relationship between the gas pressure and the melt flow rate were studied. To determine the effects of the gas flow on gas-assisted coextrusion, a three-dimensional simulation was developed in which the gas layer was considered as an independent flow zone. The influence of the gas pressure, gas layer thickness and melt flow rate on the melts’ profile and the deflection deformation degree (DDD) was studied, and the relationship between the gas pressure, gas layer thickness and melt flow rate was obtained. The numerical results indicated that a traditional coextrusion flow zone in front of a gas-assisted coextrusion flow zone could allow products to avoid a gas groove. The quality of the products could be improved by decreasing the gas pressure and gas layer thickness or increasing the melt flow rate. Additionally, the minimum gas pressure decreased as the gas layer thickness increased and increased as the melt flow rate increased. The numerical results were in good agreement with the experimental results, despite a slight quantitative error. Therefore, reasonably controlling the gas flow condition is key in practical applications of gas-assisted coextrusion, and the effects of the gas layer should be considered in gas-assisted coextrusion simulations.

Spindle assembly checkpoint regulation of chromosome segregation in mammalian oocytes

2013 ◽  
Vol 25 (3) ◽  
pp. 472 ◽  
Author(s):  
Zbigniew Polanski
Keyword(s):  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Cell Cycle Control ◽  
Genetic Material ◽  
Spindle Assembly ◽  
Female Meiosis ◽  
Mammalian Oocyte ◽  
Oocyte Meiosis ◽  
Surveillance Mechanism

The spindle assembly checkpoint (SAC) is a surveillance mechanism that monitors the quality of the spindle during division and blocks anaphase entry in the presence of anomalies that could result in erroneous segregation of the chromosomes. Because human aneuploidy is mainly linked to the erroneous segregation of genetic material in oocytes, the issue of the effectiveness of the SAC in female meiosis is especially important. The present review summarises our understanding of the SAC control of mammalian oocyte meiosis, including its possible impact on the incidence of embryonic aneuploidy. Owing to the peculiarities of cell cycle control in female meiosis, the integration of the SAC within such a specific environment results in several unusual situations, which are also discussed.

Machining Center Worktable Static Stiffness Spectrum Drawing and Analysis

2011 ◽  
Vol 65 ◽  
pp. 84-87
Author(s):  
Gong Xue Zhang ◽  
Yu Fang Gu ◽  
Bing Bing Han ◽  
Xiao Kai Shen
Keyword(s):  
Optimal Design ◽  
Product Quality ◽  
High Speed ◽  
High Speed Machining ◽  
Static Stiffness ◽  
Main Work ◽  
Machining Center ◽  
Ansys Workbench

The main work is calculating and analyzing the worktable’s static stiffness in different positions, and drawing 3D static stiffness spectrum of the worktable in Z direction according to the analyzing results. DVG850 High-speed machining centre is taken as the research object, to establish the solid modal in ANSYS Workbench and analyze the worktable’s static stiffness in different positions. and the paper uses its worktable as the researching object. According to the results the spectrum of the static stiffness of the worktable is drawing in Matlab. The spectrum shows that the more the position is near the edge, the larger the static stiffness is, and it changes faster, however the middle is smaller. This spectrum has certain directive significance for the optimal design and improvement of product quality of design.

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