scholarly journals Investigation of a multi-ball, automatic dynamic balancing mechanism for eccentric rotors

2007 ◽  
Vol 366 (1866) ◽  
pp. 705-728 ◽  
Author(s):  
K Green ◽  
A.R Champneys ◽  
M.I Friswell ◽  
A.M Muñoz
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Steady State ◽  
Transient Response ◽  
Nonlinear Model ◽  
Practical Implementation ◽  
Dynamic Balancing ◽  
Qualitative And Quantitative ◽  
Simulation Results ◽  
Experimental Rig

This paper concerns an analytical and experimental investigation into the dynamics of an automatic dynamic balancer (ADB) designed to quench vibration in eccentric rotors. This fundamentally nonlinear device incorporates several balancing masses that are free to rotate in a circumferentially mounted ball race. An earlier study into the steady state and transient response of the device with two balls is extended to the case of an arbitrary number of balls. Using bifurcation analysis allied to numerical simulation of a fully nonlinear model, the question is addressed of whether increasing the number of balls is advantageous. It is found that it is never possible to perfectly balance the device at rotation speeds comparable with or below the first natural, bending frequency of the rotor. When considering practical implementation of the device, a modification is suggested where individual balls are contained in separate arcs of the ball race, with rigid partitions separating each arc. Simulation results for a partitioned ADB are compared with those from an experimental rig. Close qualitative and quantitative match is found between the theory and the experiment, confirming that for sub-resonant rotation speeds, the ADB at best makes no difference to the imbalance, and can make things substantially worse. Further related configurations worthy of experimental and numerical investigation are proposed.

scholarly journals Study on Fluorine Pollution in a Slag Yard

2019 ◽  
Vol 9 (5) ◽  
pp. 847
Author(s):  
Lide Wei ◽  
Changfu Wei ◽  
Sugang Sui
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Numerical Simulations ◽  
Solute Transport ◽  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Laboratory Studies ◽  
Survey Results ◽  
Simulation Results

This paper suggests a large-scale three-dimensional numerical simulation method to investigate the fluorine pollution near a slag yard. The large-scale three-dimensional numerical simulation method included an experimental investigation, laboratory studies of solute transport during absorption of water by soil, and large-scale three-dimensional numerical simulations of solute transport. The experimental results showed that the concentrations of fluorine from smelting slag and construction waste soil were well over the discharge limit of 0.1 kg/m3 recommended by Chinese guidelines. The key parameters of the materials used for large-scale three-dimensional numerical simulations were determined based on an experimental investigation, laboratory studies, and soil saturation of survey results and back analyses. A large-scale three-dimensional numerical simulation of solute transport was performed, and its results were compared to the experiment results. The simulation results showed that the clay near the slag had a high saturation of approximately 0.9, consistent with the survey results. Comparison of the results showed that the results of the numerical simulation of solute transport and the test results were nearly identical, and that the numerical simulation results could be used as the basis for groundwater environmental evaluation.

scholarly journals Improving The Manoeuvrability of Electric Vehicle with Four-Wheel Drive and Four-Wheel Steering – A Nonlinear Model Vehicle Dynamics Approach

2018 ◽  
Vol 225 ◽  
pp. 05016
Author(s):  
M.I. Ishak ◽  
P.M. Heerwan ◽  
M.A.H. Rasid
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Electric Vehicle ◽  
Nonlinear Model ◽  
Rotational Speed ◽  
Vehicle Dynamics ◽  
High Speed ◽  
Passive Control ◽  
Vehicle Speed ◽  
Linear And Nonlinear

The dynamics motion of a vehicle is inherently a nonlinear dynamics system especially at high speed. Majority of past researches on four-wheel steering (4WS) vehicle adopt easier way of modelling a control system based on vehicle with linear dynamic equation of motion. This paper study on the vehicle dynamics of an electric vehicle with 4WD and 4WS based on nonlinear vehicle dynamic approach. A numerical simulation was performed to analyse the variance of a linear model and nonlinear model during cornering at various constant speed. The results show that during low speed cornering at 10 km/h, the linear and nonlinear model produced similar steady state cornering based on the trajectory and yaw rotational speed. However, the variants of linear and nonlinear started to appear as the vehicle speed increase. By obtaining the steady state cornering speed, another numerical simulation was performed to analyse the characteristics of the 4WD and 4WS electric vehicle. A passive control of the rear wheels’ steer angle was implement in the simulation. The results show that the parallel steering mode decreased the yaw rotational speed which broaden the trajectory of the cornering, while the opposite steering mode increased the yaw rotational speed that led to a tighter trajectory during cornering.

Theoretical Analysis and Experimental Investigation on Designing Method of Micro-Groove Heat Pipe

2011 ◽  
Vol 483 ◽  
pp. 350-353
Author(s):  
Tian Han ◽  
Xiao Wei Liu ◽  
Ning Cui
Keyword(s):  
Experimental Investigation ◽  
Steady State ◽  
Heat Pipe ◽  
Transport Capacity ◽  
Maximum Heat ◽  
Interface Friction ◽  
One Dimensional ◽  
Steady State Model ◽  
Simulation Results ◽  
Designing Method

In this paper, a kind of one-dimensional steady-state model is used to analyze and simulate the capillary motion of the working material in micro heat pipe. The character of this model is that it includes the influence of the interface friction, and the influence of the friction to the micro heat pipe’s performance is also simulated and analyzed. The maximum heat transport capacity and the optimizing size of the grooves are calculated by this model. Some experiments have been carried out to evaluate the simulation results.

NONLINEAR BEHAVIORS OF GEAR SHIFTING DIGITAL PHASE LOCKED LOOPS

2012 ◽  
Vol 22 (08) ◽  
pp. 1250204 ◽  
Author(s):  
XI CHEN ◽  
BINGO WING-KUEN LING ◽  
LI-MIN SUN
Keyword(s):  
Numerical Simulation ◽  
Adaptive Control ◽  
Steady State ◽  
Initial Conditions ◽  
Phase Locked Loops ◽  
Control Parameters ◽  
Dynamical Behaviors ◽  
Digital Phase Locked Loops ◽  
Simulation Results ◽  
Nonlinear Behaviors

Applying gear shifting algorithms to the implementation of Phase Locked Loops (PLLs) can significantly improve their performances. However, the behaviors of gear shifting digital PLLs (GSDPLLs) have not been fully studied due to the existence of newly adaptive control parameters. These parameters play a very important role in the design of GSDPLLs. In this paper, various nonlinear behaviors of GSDPLLs including the steady state periodic behaviors, divergent behaviors and chaotic behaviors, are studied. In particular, the effects of the initial conditions of GSDPLLs on their dynamical behaviors are investigated. The obtained results are useful for the design of GSDPLLs. Numerical simulation results are presented for illustrations.

Recent Research and Future Challenges in the Simulation of Hydraulic Seals

2009 ◽  
Author(s):  
Richard F. Salant ◽  
Bo Yang ◽  
Azam Thatte
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Future Research ◽  
Future Challenges ◽  
Simulation Results ◽  
Rod Seals

Recent numerical simulation results of hydraulic rod seals are reviewed. These include steady-state simulations of U-cup seals. Challenges for future research are discussed.

scholarly journals A Multivariable Adaptive Control Approach for Stabilization of a Cart-Type Double Inverted Pendulum

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
I. Hassanzadeh ◽  
A. Nejadfard ◽  
M. Zadi
Keyword(s):  
Steady State ◽  
Nonlinear Model ◽  
Degrees Of Freedom ◽  
Inverted Pendulum ◽  
Feedback Gain ◽  
Practical Implementation ◽  
Model Parameters ◽  
Lagrange Equations ◽  
Control Approach ◽  
Input Structure

This paper considers the design and practical implementation of linear-based controllers for a cart-type double inverted pendulum (DIPC). A constitution of two linked pendulums placed on a sliding cart, presenting a three Degrees of Freedom and single controlling input structure. The controller objective is to keep both pendulums in an up-up unstable equilibrium point. Modeling is based on the Euler-Lagrange equations, and the resulted nonlinear model is linearized around up-up position. First, the LQR method is used to stabilize DIPC by a feedback gain matrix in order to minimize a quadratic cost function. Without using an observer to estimate the unmeasured states, in the next step we make use of LQG controller which combines the Kalman-Bucy filter estimation and LQR feedback control to obtain a better steady-state performance, but poor robustness. Eventually, to overcome the unknown nonlinear model parameters, an adaptive controller is designed. This controller is based on Model Reference Adaptive System (MRAS) method, which uses the Lyapunov function to eliminate the defined state error. This controller improves both the steady-state and disturbance responses.

Avalanche Features in Silicon Schottky-FETs in Accordance with Numerical Simulation Results

2006 ◽  
Vol 65 (16) ◽  
pp. 1533-1546
Author(s):  
Yu. Ye. Gordienko ◽  
S. A. Zuev ◽  
V. V. Starostenko ◽  
V. Yu. Tereshchenko ◽  
A. A. Shadrin
Keyword(s):  
Numerical Simulation ◽  
Simulation Results
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