Experimental research on cage dynamic characteristics of angular contact ball bearing

2019 ◽  
Vol 20 (2) ◽  
pp. 204
Author(s):  
Qingqing Li ◽  
Xiaoyang Chen ◽  
Tao Zhang ◽  
Shijin Chen ◽  
Jiaming Gu
Keyword(s):  
Dynamic Characteristics ◽  
Performance Test ◽  
Rotation Speed ◽  
Dimensional Space ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Axial Displacement ◽  
Mass Center ◽  
Angular Contact Ball Bearing ◽  
Controllable Motion

The dynamic performance and life of the precise bearing, even abnormal operation and early failure are affected directly by the complex and unstable motion of the cage. Based on the cage dynamic performance test device with controllable motion of inner and outer rings, respectively, the dynamic characteristics of the cage were studied under different rotating speeds and loads, while inner ring rotated with outer ring fixed and inner–outer rings rotated reversely. Then the trajectory of the cage mass center was drawn through experimental study. The three-dimensional space motions of cage reveal that, when only inner ring rotates, the trajectories of cage mass center are approximately circular under axial load, and the amplitude of the axial displacement raises with the increase of the rotation speeds. With the increase of radial loads, the cage mass center trajectories are shaking from a circle to a small area on the side of the bearing center. When the inner–outer rings rotate in the opposite direction, the rotation speed of the cage is greatly reduced, and the mass center trajectories of the cage oscillate irregularly on side of the bearing center. As the relative rotation speed of rings increases, the axial displacement fluctuation enlarges. With the increase of the radial loads, the axial fluctuation decreases.

Dynamic Performance Analysis for a Butterfly-Shaped Arch Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 74-78
Author(s):  
Hai Yun Huang ◽  
Xiang Rong Yuan ◽  
Ka Hong Cai
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Test ◽  
Structural Dynamic ◽  
Arch Bridge ◽  
Calculation Results ◽  
Dynamic Performance Analysis

The dynamic characteristics are not only the important indexes for evaluating the bridge structural rigidity, but also the principal parameters for structural dynamic analysis and earthquake resistant analysis. In this paper, a three dimensional solid finite element model for a butterfly-shape arch bridge in Zhongshan city was established to analyze the dynamic characteristics. By comparison the numerical calculation results with measured results of the dynamic loading test, an analysis and evaluation of the dynamic performance of this new type spatial arch bridge was made, and can serve as reference to the dynamic analysis and seismic design of similar bridges.

Locus of the Axis of Vibration for a Vibrating System With Variable Location of a Mass Center

2000 ◽  
Author(s):  
Byung Ju Dan ◽  
Yong Je Choi
Keyword(s):  
Vibration Analysis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Analytical Form ◽  
Point Of View ◽  
Information Storage ◽  
Mode Shapes ◽  
Storage Device ◽  
Geometrical Approach ◽  
Mass Center

Abstract A typical approach to a linear vibration analysis of an elastically supported single rigid body is to rearrange a dynamic model into a corresponding eigenvalue problem. From the geometrical point of view, the eigenvectors in the planar vibration analysis can be interpreted as pure rotations about the vibration center or pure translations. In a three dimensional space, they represent repetitive twisting motions about the axes of vibrations. By taking a geometrical approach to the vibration analysis, the vibration mode shapes may be better understood. In this paper, the influence of variable location of a mass center on the locations of the axes of vibrations and the natural frequencies are investigated by means of the locus of the axis of vibration expressed in analytical form, which represents the geometrical locus of the eigenvector. A numerical example is used to clearly illustrate the vibration phenomena of an optical pick-up used in an information storage device.

scholarly journals Synchronous state of unbalanced rotors in a three-dimensional space and far-resonance system

2019 ◽  
Vol 234 (1) ◽  
pp. 108-122
Author(s):  
Pan Fang ◽  
Huan Peng ◽  
Du Changcheng ◽  
Min Zou ◽  
Duyu Hou ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Dimensional Space ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Parameter Method ◽  
Synchronous State ◽  
Rotation Direction ◽  
Key Factor ◽  
Screening Efficiency ◽  
Three Dimensional Space

The unreasonable dynamic characteristics results in decrease of screening efficiency of the vibrating screen. However, the synchronous behavior of motors is key factor to determine dynamic characteristics of the screens. In this paper, two unbalanced rotors actuated with motors in a three-dimensional space are proposed. To understand the synchronous mechanism, the dynamic equation of the system is firstly confirmed based on Lagrangian formulation; meanwhile, synchronization condition of the system is calculated with average and small parameter method; then, synchronization stability of the system is explored by Lyapunov method; finally, some numerical simulations are given to validate the theoretical computations. It is found that, to implement the stable synchronous rotation between the rotors, the values of the parameter in this system must be satisfied by synchronous condition and synchronous stability; the synchronous state is determined by the rotation direction, the damping ratio, the frequency ratio, and the motor position; the system is a planar motion when the identical mass rotors oppositely actuated, but the system is a spatial motion in the other cases.

A program for determining the area of the object entering the IR sensor grid, as well as determining the dynamic characteristics

2021 ◽  
Author(s):  
Victor Kuznetsov ◽  
Vladislav Litvinenko ◽  
Egor Bykov ◽  
Vadim Lukin
Keyword(s):  
Dynamic Characteristics ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Threshold Value ◽  
Threshold Level ◽  
Infrared Sensors ◽  
Laser Sensors ◽  
Sensor Channel ◽  
The Difference ◽  
The Given

Currently, to evaluate the dynamic characteristics of objects, quite a large number of devices are used in the form of chronographs, which consist of various optical, thermal and laser sensors. Among the problems of these devices, the following can be distinguished: the lack of recording of the received data; the inaccessibility of taking into account the trajectory of the object flying in the sensor area, as well as taking into consideration the trajectory of the object during the approach to the device frame. The signal received from the infrared sensors is recorded in a separate document in txt format, in the form of a table. When you turn to the document, data is read from the current position of the input data stream in the specified list by an argument in accordance with the given condition. As a result of reading the data, it forms an array that includes N number of columns. The array is constructed in a such way that the first column includes time values, and columns 2...N- the value of voltage . The algorithm uses cycles that perform the function of deleting array rows where there is a fact of exceeding the threshold value in more than two columns, as well as rows where the threshold level was not exceeded. The modified array is converted into two new arrays, each of which includes data from different sensor frames. An array with the coordinates of the centers of the sensor operation zones was created to apply the Pythagorean theorem in three-dimensional space, which is necessary for calculating the exact distance between the zones. The time is determined by the difference in the response of the first and second sensor frames. Knowing the path and time, we are able to calculate the exact speed of the object. For visualization, the oscillograms of each sensor channel were displayed, and a chronograph model was created. The chronograph model highlights in purple the area where the threshold has been exceeded.

Three-Dimensional Aerial Image Interface, 3DAII

2019 ◽  
Vol 31 (5) ◽  
pp. 657-670 ◽  
Author(s):  
Takafumi Matsumaru ◽  
◽  
Asyifa Imanda Septiana ◽  
Kazuki Horiuchi
Keyword(s):  
Performance Test ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Aerial Image ◽  
Robotic Arm ◽  
Movement Speed ◽  
Movement Direction ◽  
Object Image ◽  
Projected Image ◽  
Dimensional Object

In this paper, we introduce the three-dimensional aerial image interface, 3DAII. This interface reconstructs and aerially projects a three-dimensional object image, which can be simultaneously observed from various viewpoints or by multiple users with the naked eye. A pyramid reflector is used to reconstruct the object image, and a pair of parabolic mirrors is used to aerially project the image. A user can directly manipulate the three-dimensional object image by superimposing a user’s hand-finger or a rod on the image. A motion capture sensor detects the user’s hand-finger that manipulates the projected image, and the system immediately exhibits some reaction such as deformation, displacement, and discoloration of the object image, including sound effects. A performance test is executed to confirm the functions of 3DAII. The execution time of the end-tip positioning of a robotic arm has been compared among four operating devices: touchscreen, gamepad, joystick, and 3DAII. The results exhibit the advantages of 3DAII; we can directly instruct the movement direction and movement speed of the end-tip of the robotic arm, using the three-dimensional Euclidean vector outputs of 3DAII in which we can intuitively make the end-tip of the robotic arm move in three-dimensional space. Therefore, 3DAII would be one important alternative to an intuitive spatial user interface, e.g., an operation device of aerial robots, a center console of automobiles, and a 3D modelling system. A survey has been conducted to evaluate comfort and fatigue based on ISO/TS 9241-411 and ease of learning and satisfaction based on the USE questionnaire. We have identified several challenges related to visibility, workspace, and sensory feedback to users that we would like to address in the future.

Experimental investigation of cage motions in an angular contact ball bearing

2017 ◽  
Vol 231 (8) ◽  
pp. 1041-1055 ◽  
Author(s):  
Baogang Wen ◽  
Hongjun Ren ◽  
Hao Zhang ◽  
Qingkai Han
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Ball Bearing ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Axial Loads ◽  
Angular Contact Ball Bearing ◽  
Radial Forces ◽  
External Loads

The commonly known effects of both the rotating speeds and external loads on the bearing dynamics or life behaviors are mostly caused by its cage dynamics, because of the complicated contact and collision interactions between the cage and other parts such as the inner or outer rings and balls. In this paper, experimental investigation of dynamic motions of a cage is carried out under various rotating speeds and external loads in a ball bearing. On a bearing test rig, the cage motions in axial and radial directions are measured by use of eddy transducers installed inside the bearing house and the subpanel. Then the measured results are analyzed by fast Fourier transform and compared at different operating conditions including rotating speeds, axial and radial forces, or moments. The three-dimensional space motions of the cage are also constructed to illustrate its different modes. Results reveal that the cage motions are typically periodic in the three directions. The motion frequencies consist of the cage rotating frequency and its multi-frequency, the inner ring rotating frequency, and also some combination frequencies of the cage and inner ring. The obtained characteristic frequencies of the cage motion in axial are similar to that in radial, but different in the variety of amplitudes under the same operating conditions. The increment of rotating speeds and axial loads of the bearing gradually make the whirl trajectories of the cage mass center regular, and enlarge its whirl radii. Instead, the whirl trajectories change from well-defined patterns to complicated ones, and its whirl radii decrease on increasing the radial loads and moments of the bearing. All the obtained experimental results are useful references for dynamic design and life prediction of high-speed and low-load bearings commonly used in many machines.

Vehicle–track interaction with consideration of rail irregularities at three-dimensional space

2020 ◽  
Vol 26 (15-16) ◽  
pp. 1228-1240
Author(s):  
Lei Xu ◽  
Qiang Zhang ◽  
Zhiwu Yu ◽  
Zhihui Zhu
Keyword(s):  
Dimensional Space ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Great Influence ◽  
Coupled Model ◽  
Hertzian Contact ◽  
Computational Stability ◽  
Contact Points ◽  
Rail Irregularities ◽  
Three Dimensional Space

Modelling of vehicle–track interaction has long been a hot and interesting topic. In multibody dynamics based on force-equilibrium methods, Hertzian contact and creep theories have been applied in vehicle–track model constructions. In another aspect, the complementarity-based methods have also been widely used in establishing vehicle–track interaction, but still having drawbacks on characterization of wheel–rail contact geometry/creepage in three-dimensional space. In this study, we draw essences from methodologies of refined wheel–rail coupling models and energy-variational principle, and a model for vehicle–track three-dimensional interactions with inclusion of rail irregularity excitations is newly developed. This model possesses high accuracy compared with Hertzian contact, FastSim, and vehicle–track coupled model in the middle-low frequency domain, and also, the advantages in computational stability are possessed. In this model, the unevenness of rail irregularities at the three-dimensional space is preliminarily considered by taking a hypothesis of normal distribution and accordingly, the wheel–rail three-dimensional constraint equations are presented. Extensively, a series of numerical examples are shown to verify the effectiveness and engineering practicability of this model. Besides, the influence of rail three-dimensional irregularities on the dynamic performance of vehicle–track systems is further explored, which shows when the trochoid of the wheel–rail contact points changes rapidly, the additional inertial effects brought out by rail irregularities might exert great influence on wheel–rail forces.

Research on Improving the Dynamic Performance of Centrifugal Pumps With Twisted Gap Drainage Blades

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Zheng-Chuan Zhang ◽  
Hong-Xun Chen ◽  
Zheng Ma ◽  
Jian-Wu He ◽  
Hui Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Centrifugal Pumps ◽  
Practical Applications

Through numerical simulation and experiments analysis, it is indicated that the hydraulic and anticavitation performance of a centrifugal pump with twisted gap drainage blades based on flow control theory can be significantly improved under certain operating conditions. In order to introduce the technology of gap drainage to practical applications, we put forward the parameter formulas of the twisted gap drainage blade to design three-dimensional new type blade, which are also proved to be effective for enhancing the dynamic characteristics of the centrifugal pump. Furthermore, a practical centrifugal pump is redesigned to be a twisted gap drainage impeller with the same structure size as the original impeller, and the nonlinear hybrid Reynolds-averaged Navier–Stokes (RANS)/large eddy simulation (LES) method is employed to simulate the hydraulic dynamic characteristics. Numerical simulation results show that the hydraulic performance and dynamic characteristics of the redesigned impeller centrifugal pump are significantly enhanced. In experiments, the twisted gap drainage blades structure not only remarkably improves the hydraulic performance and the pressure pulsation characteristics of the centrifugal pump but also reduces the vibration intensity.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

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