scholarly journals Passive Multi-Layer Composite Damper of Flat Belt Tensioner Idler

2021 ◽  
Vol 11 (7) ◽  
pp. 3267
Author(s):  
Zuzana Murčinková ◽  
Jozef Živčák ◽  
Jozef Zajac ◽  
Pavel Adamčík
Keyword(s):  
Dynamic Properties ◽  
Testing Machine ◽  
Roller Bearing ◽  
Dynamic Effects ◽  
Complex Dynamic ◽  
System A ◽  
At Resonance ◽  
Layer Composite ◽  
Passive Dampers ◽  
Amplitude And Frequency Modulation

In this study, the effect of multi-layer composite passive dampers on the dynamic properties of a mechanical system (a testing machine tool bench) was tested. Passive dampers are characterized by a layered structure, with each layer consisting of a specific structure of different materials, preferably foam polymers. The dynamic excitation is caused by a flat belt driving the rotor roller bearing by direct contact of the flat belt and bearing pin at a frequency of 1170–2170 Hz. The dynamic effects of the flat belt directly affect the complex dynamic effects inside rotor bearing, mainly torsional vibrations. A significant modification in the amplitude and frequency modulation and other evaluated dynamic parameters was obtained. By implementing passive dampers and modifying the mass and material damping, a decrease in amplitude at resonance of almost 30% was achieved.

scholarly journals Portrayal of Complex Dynamic Properties of Sugarcane Defensin 5 by NMR: Multiple Motions Associated with Membrane Interaction

Structure ◽  
2011 ◽  
Vol 19 (1) ◽  
pp. 26-36 ◽  
Author(s):  
Viviane Silva de Paula ◽  
Guilherme Razzera ◽  
Eliana Barreto-Bergter ◽  
Fabio C.L. Almeida ◽  
Ana Paula Valente
Keyword(s):  
Dynamic Properties ◽  
Complex Dynamic ◽  
Membrane Interaction

The Effect of Compositional and Testing Variations on the Dynamic Properties of Compounds Based on Styrene-Butadiene and Polybutadiene Elastomers

1971 ◽  
Vol 44 (1) ◽  
pp. 258-270 ◽  
Author(s):  
D. A. Meyer ◽  
J. G. Sommer
Keyword(s):  
Carbon Black ◽  
Storage Modulus ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Dynamic Stiffness ◽  
Rate Of Change ◽  
Complex Dynamic ◽  
Spring Rate ◽  
Styrene Butadiene ◽  
Black Level

Abstract Important factors of potential use for manipulating static and dynamic stiffness and the damping characteristics of compounds based on styrene-butadiene and polybutadiene elastomers and their blends have been outlined. Their characteristics have been compared with those of IIR and EPDM compounds. The effects of variations in composition are quantitatively defined to assist the compounder in combining these effects in a manner that will lead to a desired combination of properties. In addition to the expected increase in static spring rate and dynamic spring rate with carbon black level, the following responses to compositional variations were found important: 1. The complex dynamic spring rate is more sharply dependent upon carbon black level than the static spring rate. 2. The complex dynamic spring rate is essentially independent of the level of crosslinking while static spring rate increases. 3. Damping coefficient is directly proportional to the level of carbon black and inversely proportional to the level of crosslinking. 4. Styrene level in a polymer blend and plasticizer composition can be used to adjust loss modulus and storage modulus at a given temperature and also to modify the rate of change of these properties with temperature. 5. The strain dependency of storage modulus was found in one instance to vary with the elastomer composition. The IIR vulcanizate, when formulated to the same static modulus, exhibited a larger strain dependence than the SBR, BR, and EPDM composition.

CALCULATION OF ADDITIONAL AXIAL FORCE OF ANGULAR-CONTACT BALL BEARINGS IN ROTOR SYSTEM

2016 ◽  
Vol 40 (4) ◽  
pp. 585-596
Author(s):  
Zhenhuan Ye ◽  
Zhansheng Liu ◽  
Liqin Wang
Keyword(s):  
Axial Force ◽  
Dynamic Properties ◽  
Descent Method ◽  
Rotor System ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
System A ◽  
Calculation Results ◽  
Relationship Of ◽  
Raphson Method

Based on a loading-deformation relationship of bearing elements and the coordination of displacement between bearings in the rotor system, a model for calculating the additional axial force of angular-contact ball bearings in a single-rotor system is established. Nonlinear equations of this model are solved through the Rapid Descent method and Newton-Raphson method. The simulation results which are based on Gupta’s example verify that both the model and solving methods in this paper are reliable. A pair of 276927NK1W1(H) angular-contact ball bearings in symmetry in the single-rotor system is used as the example, calculation results of the additional axial force of bearings from the model in this paper and from the ISO method are compared and the influence of bearing geometry parameters and working conditions on the additional axial force is further studied. This model and its conclusions could provide the basic data and reference for analyzing the carrying ability and dynamic properties of rolling bearings.

scholarly journals Low-amplitude dynamic tests of fine gravel in a resonant column

2019 ◽  
Vol 97 ◽  
pp. 04024
Author(s):  
Zaven Ter-Martirosyan ◽  
Evgeny Sobolev ◽  
George Anzhelo
Keyword(s):  
Mechanical Properties ◽  
Dynamic Properties ◽  
Sample Volume ◽  
Coarse Grained ◽  
Software Systems ◽  
Resonant Column ◽  
Dynamic Effects ◽  
Laboratory Equipment ◽  
Aggregate Fractions ◽  
Sample Assembly

Construction of industrial and civil buildings, taking into account the dynamic effects on the foundations, requires special experiments on the mechanical properties of soils. This article presents the results of studying the dynamic properties of coarse gravelly soils using the resonant column method. These studies are relevant, since the determination of the dynamic properties of coarse-grained soils under laboratory conditions is associated with a restriction on the size of the fractions in the sample volume. This circumstance leads to the fact that at the moment most of the laboratory tests of the dynamic properties of coarse-grained soils are performed on smaller aggregate fractions, which, in general, significantly reduces the resulting mechanical properties of soils. It does not reflect the real operation of the foundation of buildings during dynamic effects. This paper presents a description of the available laboratory equipment, the sequence of preparation of samples of coarse grained crushed stone soil and sample assembly in the working chamber of the installation. The article contains the main graphs characterizing the change in shear modulus and damping coefficient depending on shear deformations. It is noted that the results obtained are particularly relevant for modeling the dynamic effects of natural and man-made character on the foundations of industrial and civil buildings, the bases of which are composed of coarse-grained soils. Dynamic parameters considered in this paper, can and must be used in numerical calculations by finite element method with the use of modern groundwater models in geotechnical software systems.

Five Pad Tilting Pad Bearing Design and Lateral Vibration Characteristics of Small Gas Turbine Supported by It and Roller Bearing

2011 ◽  
Author(s):  
Jin Woong Ha ◽  
Ji Ho Myung ◽  
Jhin Ik Suk
Keyword(s):  
Rigid Body ◽  
Gas Turbine ◽  
Dynamic Properties ◽  
Roller Bearing ◽  
Rigid Body Mode ◽  
Conical Shape ◽  
Tilting Pad ◽  
Bearing Design ◽  
Industrial Gas Turbine ◽  
Selection Of

In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the static and dynamic characteristics of a five pad tilting pad bearing for the LBP and LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

The Nonlinear Internal Resonance Analysis of a Rotary Truncated Conical Shell

2006 ◽  
Author(s):  
Changping Chen ◽  
Liming Dai
Keyword(s):  
Conical Shell ◽  
Dynamic Properties ◽  
Harmonic Balance Method ◽  
Multiple Scale ◽  
High Order ◽  
Internal Dynamic ◽  
Conical Shells ◽  
System A ◽  
Truncated Conical Shell ◽  
Low Order

Truncated conical shell is an important structure that has been widely applied in many engineering fields. The present paper studies the internal dynamic properties of a truncated rotary conical shell with considerations of intercoupling the high and low order modals by utilizing Harmonic Balance Method. To disclosure the detailed intercoupling characteristics of high order modal and low order modal of the system, a truncated shallow shell is studied and the internal response properties of the system is investigated by using the Multiple Scale Method. Abundant dynamic characteristics are found in the research of this paper. It is found in the research of the paper that the high-order modals of rotating conical shells have significant effects to the amplitude and frequency of the shells.

Dynamic Properties of Rubber. Dependence on Pigment Loading

1941 ◽  
Vol 14 (4) ◽  
pp. 842-857 ◽  
Author(s):  
S. D. Gehman ◽  
D. E. Woodford ◽  
R. B. Stambaugh
Keyword(s):  
Zinc Oxide ◽  
Internal Friction ◽  
Dynamic Modulus ◽  
Dynamic Properties ◽  
Modulus Ratio ◽  
Volume Loading ◽  
Static Modulus ◽  
Black Clay ◽  
At Resonance ◽  
Wide Range

Abstract Dynamic properties are specific for different pigments. Curves show the dependence on pigment loading of the dynamic modulus, ratio of dynamic to static modulus, internal friction, dynamic resilience, and calculated relative heat generation at constant force and at constant amplitude. For the same volume loading, the dynamic modulus and internal friction rank in the order: Superspectra, channel black, zinc oxide, clay, blanc fixe, Thermatomic black, i.e., roughly in the order of particle size. The calculated dynamic resilience depends on the ratio of the modulus to the internal friction and increases in the order Superspectra, channel black, clay, Thermatomic black, blanc fixe, zinc oxide. The dynamic modulus shows an almost linear relation with the internal friction for different loadings of the same pigment. The dynamic modulus is independent of the frequency in the range 20–150 cycles per second. It depends on the amplitude, an effect which may be connected with the warming of the test-piece due to the vibration. The amplitude at resonance for the same driving force is approximately constant at all frequencies for a given rubber compound. The results show the wide range of dynamic properties obtainable with different pigments, and bring out the general principles involved in their use for dynamic purposes.

scholarly journals BRLO-Tree: A Data Structure Used for 3D GIS Dynamic Scene Rendering

2015 ◽  
Vol 15 (4) ◽  
pp. 124-137 ◽  
Author(s):  
Wenju Wang ◽  
Zhang Xuan ◽  
Liujie Sun ◽  
Zhongmin Jiang ◽  
Jingjing Shang
Keyword(s):  
Data Structure ◽  
Large Scale ◽  
Three Dimensional ◽  
Level Of Detail ◽  
Dynamic Scene ◽  
3D Gis ◽  
Dynamic Scenes ◽  
Complex Dynamic ◽  
3D Objects ◽  
System A

Abstract BRLO-Tree (Block-R-Tree-Loose-Octree) is presented in this paper based on the R-Tree and Loose-Octree. The aim of the structure is to visualize the large scale and complex dynamic scenes in a 3D (three-dimensional) GIS (Geographic Information System). A new method of clustering rectangles to construct R-tree based on an improved K-means algorithm is put forward. Landform in 3D GIS is organized by R-Tree. The block is used as the basic rendering unit. The 3D objects of each block are respectively organized by a Loose-Octree. A series of techniques, based on this data structure, such as LOD (Level of Detail), relief impostors are integrated. The results of the tests show that BRLO-Tree cannot only support the large scale 3D GIS scene exhibition with wandering and fighting, but it can also efficiently manage the models in a dynamic scene. At the same time, a set of integrated techniques based on BRLO-Tree can make the rendering pictures more fluence and the rendering time vastly improved.

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