scholarly journals Bearing Seat Vibration Modes Undergoing Unbalanced Excitation of Multirotating Drums

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Yu Li ◽  
Zhong Tang ◽  
Xinzhong Wang ◽  
Hao Zhang ◽  
Yaoming Li
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Vibration Amplitude ◽  
Vibration Modes ◽  
Response Model ◽  
Response Characteristics ◽  
Transmission Modes ◽  
Combine Harvester ◽  
Seat Vibration ◽  
Poor Stability

Transmission modes of multiple rotating parts on combine harvester are complex and diverse, which resulted in large vibration and poor stability when the entire machine is harvesting. Aiming at the complex vibration problem of the combine harvester threshing system, this paper established the dynamic response model of the multidrum parallel system under different transmission modes and solved the vibration characteristics of the system. An experiment on the axial unbalance response of the parallel drum system under different transmission modes was carried out. The results show that the internal units of the threshing system form a whole through the transmission system, which causes the unbalanced response of the system to be superimposed on parallel threshing drums, thereby increasing the vibration amplitude. In addition, the change of the transmission mode will cause the vibration transmission path in the system to change greatly, and the boundary conditions of the system will be changed at the same time, which will eventually lead to the change of the unbalanced response characteristics.

scholarly journals The Dynamic Response and Failure Model of Thin Plate Rock Mass under Impact Load

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Feng Li ◽  
Xinhui Dong ◽  
Yue Wang ◽  
Hanwu Liu ◽  
Chuang Chen ◽  
...  
Keyword(s):  
Rock Mass ◽  
Dynamic Response ◽  
Boundary Conditions ◽  
Failure Mechanism ◽  
Thin Plate ◽  
Impact Load ◽  
Vibration Modes ◽  
Plate Model ◽  
Damage And Failure ◽  
Dynamic Disaster

The layered rock mass widely exists in mining, construction, transportation, and water conservancy projects, and the damage phenomena of plate crack and spalling often occurs in the process of coal and rock dynamic disaster in deep mining. Therefore, the rock mass nearby excavation surface is usually considered to be composed of layers of thin plate rock mass to reveal the damage and failure mechanism of rock mass. In the whole dynamic process of mining and coal and rock dynamic disaster, rock mass would bear the dynamic disturbance from mine earthquake, and at present, the mechanical characteristics of rock mass are mainly studied under static load, while dynamic mechanical response characteristics and the mechanisms of dynamic damage, failure, and disaster-causing are still unclear. This study mainly focused on the dynamic response characteristic and failure mechanism of rock mass based on a rectangular thin plate model. The frequency equations and deflection equations of the thin plate rock mass with different boundary conditions (S-F-S-F, S-C-S-C, and C-C-C-C) were established under free vibration by the thin plate model and the dual equation of the Hamilton system, and the deflection equations under impact load were derived based on the Duhamel integral. And then, the effective vibration modes of the thin plate rock mass with different boundary conditions and their natural frequencies were obtained by Newton’s iterative method. Based on the third-strength theory and the numerical simulation results by LS-DYNA, the maximum shear of the effective vibration modes and the processes of damage and failure under impact load were analyzed. The research results showed that the initial position of damage and failure may be determined by effective vibration mode with the lowest frequency; the develop tendency of which by the combined actions of other effective vibration modes and the effective vibration modes with lower frequency could have greater influence on the process of damage and failure of the thin plate rock mass, which are beneficial to revealing the mechanism of coal and rock dynamic disaster.

Intracellular Dynamic Response Characteristics of Pineal Photoreceptors

1984 ◽  
Vol 16 (1-2) ◽  
pp. 119-122
Author(s):  
Y. Morit ◽  
K. Segi ◽  
M. Samejima ◽  
T. Nakamura
Keyword(s):  
Dynamic Response ◽  
Response Characteristics ◽  
Dynamic Response Characteristics ◽  
Pineal Photoreceptors ◽  
Intracellular Dynamic

Dynamic response characteristics of the plynlimon catchments and preliminary analysis of relationships to physical descriptors

1995 ◽  
Vol 6 (5) ◽  
pp. 465-472 ◽  
Author(s):  
C. E. M. Sefton ◽  
P. G. Whitehead ◽  
A. Eatherall ◽  
I. G. Littlewood ◽  
A. J. Jakeman
Keyword(s):  
Dynamic Response ◽  
Preliminary Analysis ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

Are the dynamic response characteristics of brachial artery flow-mediated dilation sensitive to the magnitude of increase in shear stimulus?

2008 ◽  
Vol 105 (1) ◽  
pp. 282-292 ◽  
Author(s):  
K. E. Pyke ◽  
J. A. Hartnett ◽  
M. E. Tschakovsky
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Dynamic Response ◽  
Phase I ◽  
Brachial Artery ◽  
Flow Mediated Dilation ◽  
Final Phase ◽  
Stimulus Magnitude ◽  
Brachial Artery Diameter ◽  
Response Characteristics

The purpose of this study was to determine the dynamic characteristics of brachial artery dilation in response to step increases in shear stress [flow-mediated dilation (FMD)]. Brachial artery diameter (BAD) and mean blood velocity (MBV) (Doppler ultrasound) were obtained in 15 healthy subjects. Step increases in MBV at two shear stimulus magnitudes were investigated: large (L; maximal MBV attainable), and small (S; MBV at 50% of the large step). Increase in shear rate (estimate of shear stress: MBV/BAD) was 76.8 ± 15.6 s−1 for L and 41.4 ± 8.7 s−1 for S. The peak %FMD was 14.5 ± 3.8% for L and 5.7 ± 2.1% for S ( P < 0.001). Both the L (all subjects) and the S step trials (12 of 15 subjects) elicited a biphasic diameter response with a fast initial phase (phase I) followed by a slower final phase. Relative contribution of phase I to total FMD when two phases occurred was not sensitive to shear rate magnitude ( r2 = 0.003, slope P = 0.775). Parameters quantifying the dynamics of the FMD response [time delay (TD), time constant (τ)] were also not sensitive to shear rate magnitude for both phases (phase I: TD r2 = 0.03, slope P = 0.376, τ r2 = 0.04, slope P = 0.261; final phase: TD r2 = 0.07, slope P = 0.169, τ r2 = 0.07, slope P = 0.996). These data support the existence of two distinct mechanisms, or sets of mechanisms, in the human conduit artery FMD response that are proportionally sensitive to shear stimulus magnitude and whose dynamic response is not sensitive to shear stimulus magnitude.

Dynamics Analysis of Refrigeration Compressor Based on Finite Element and Experimental Modes

2012 ◽  
Vol 499 ◽  
pp. 238-242
Author(s):  
Li Zhang ◽  
Hong Wu ◽  
Yan Jue Gong ◽  
Shuo Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Modal Analysis ◽  
Natural Frequency ◽  
High Precision ◽  
3D Model ◽  
Finite Element Models ◽  
Dynamics Analysis ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

Based on the 3D model of refrigeration's compressor by Pro/E software, the analyses of theoretical and experimental mode are carried out in this paper. The results show that the finite element models of compressor have high precision dynamic response characteristics and the natural frequency of the compressor, based on experimental modal analysis, can be accurately obtained, which will contribute to further dynamic designs of mechanical structures.

A Rapid Analysis Method for Microgyroscope Using System Vibration Modes

2009 ◽  
Vol 60-61 ◽  
pp. 353-356
Author(s):  
Guang Jun Liu ◽  
An Lin Wang ◽  
Zi Yi Yu ◽  
Xing Yang ◽  
Tao Jiang
Keyword(s):  
Performance Analysis ◽  
Dynamic Response ◽  
Computing Time ◽  
State Space Model ◽  
Rapid Analysis ◽  
Vibration Modes ◽  
Analysis Method ◽  
Space Model ◽  
System Equation ◽  
System Vibration

This paper proposes a rapid dynamic analysis method for microgyroscope using system vibration modes to solve the problems concerning to the computing time in the performance analysis of microgyroscope. The results of eigenvalue solution are employed to construct the state space model. The response of the microgyros cope can be reconstructed as a response superposition of the vibration modes, and then the system equation is decoupled into an uncoupled equation. The dynamic response of the microgyroscope can be calculated by a simple superposition.

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