Effects of the passive electromagnetic damper on the behavior of a fluid-conveying pipeline

2018 ◽  
Vol 233 (7) ◽  
pp. 2329-2339 ◽  
Author(s):  
Omid Kavianipour
Keyword(s):  
Fluid Velocity ◽  
Electric Energy ◽  
Ball Screw ◽  
Dissipated Energy ◽  
Damping Force ◽  
Electromagnetic Damping ◽  
Transversal Force ◽  
The Stability ◽  
Pipeline Vibration ◽  
Electromagnetic Damper

This paper studies the passive electromagnetic damper effects on the behavior of a pipeline conveying fluid. In this work, a uniform cantilever Euler–Bernoulli beam, a follower force, and a transversal force are utilized for modeling of the pipe, fluid force, and electromagnetic damping force, respectively. The passive electromagnetic damper includes a permanent-magnet DC motor, a ball screw, and a nut. The most important purpose of this study is first to decrease the pipe vibration amplitude resulting from the fluid velocity and then transform the dissipated energy into the electric energy. To achieve this goal, the stability and vibration of the model were investigated using Ritz and Newmark methods. The effects of the electromagnetic damper characteristics on the critical velocity were considered first, and then the energy storage of the passive electromagnetic damper was inspected. The results of simulation showed that the passive electromagnetic damper can simultaneously reduce the pipeline vibration and store energy up to 4.3 [mW] for low fluid flow velocity.

scholarly journals Multimode Coordination Control of a Hybrid Active Suspension

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Fa-Rong Kou ◽  
Dong-Dong Wei ◽  
Lei Tian
Keyword(s):  
Mr Damper ◽  
Active Suspension ◽  
Suspension System ◽  
Ball Screw ◽  
Damping Force ◽  
Active Mode ◽  
Damping Control ◽  
Electromagnetic Damping ◽  
Regenerative Energy ◽  
Suspension Structure

In order to effectively realize the damping control and regenerative energy recovery of vehicle suspension, a new kind of hybrid active suspension structure with the ball screw actuator and magnetorheological (MR) damper is put forward. Firstly, for the analysis of the suspension performance, a quarter dynamic model of vehicle hybrid suspension is established, and at the same time, the mathematical models of MR damper and ball screw actuator are founded. Secondly, the active mode with damping switching control of the hybrid suspension and the semiactive mode with feedback adjustment of the electromagnetic damping force of the hybrid suspension are analyzed. Then, the multimode coordinated control system of the hybrid suspension is designed. Under the cyclic driving condition, the damping performance and energy consumption characteristics of the hybrid suspension are simulated by MATLAB/Simulink software. Finally, the bench tests of the hybrid suspension system are done. The simulation and experimental results show that compared with passive suspension, the root mean square of the sprung mass acceleration of the hybrid suspension with the active mode and semiactive mode is, respectively, reduced by 39% and 16% under the random road. The damping effect of the hybrid suspension system is obvious.

Analysis the characteristic of energy and damage of coal-rock composite structure under cycle loading

2021 ◽  
Author(s):  
Tan Li ◽  
Guangbo Chen ◽  
Zhongcheng Qin ◽  
Qinghai Li
Keyword(s):  
Cyclic Loading ◽  
Elastic Energy ◽  
Composite Structure ◽  
Calculation Method ◽  
Composite Structures ◽  
Damage Variable ◽  
Dissipated Energy ◽  
Height Ratio ◽  
Coal Rock ◽  
The Stability

Abstract The stability of coal-rock composite structures is of great significance to coal mine safety production. To study the stability and deformation failure characteristics of the coal-rock composite structure, the uniaxial cyclic loading tests of the coal-rock composite structures with different coal-rock height ratios were carried out. Lithology and coal-rock height ratio play an important role in the energy dissipation of coal-rock composite structures. The higher the coal-rock height ratio, the greater the average elastic energy and dissipated energy produced per cycle of coal-rock composite structures, the smaller the total elastic energy and dissipated energy produced in the process of cyclic loading. Based on the difference of damage variables calculated by dissipative energy method and acoustic emission method, a more sensitive joint calculation method for calculating damage variable was proposed. The joint damage variable calculation method can more accurately and sensitively reflect the damage of coal-rock composite structure under cyclic loading. The macroscopic crack first appears in the coal specimen in the coal-rock composite structure, the degree of broken coal specimens in the composite structure is inversely proportional to the coal-rock height ratio. The strength and deformation characteristics of the coal-rock composite structure are mainly affected by coal sample in the composite structure.

Assessing the Maximum Stability of the Nonconvective Zone in a Salinity-Gradient Solar Pond

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
A. A. Abdullah ◽  
K. A. Lindsay
Keyword(s):  
Salinity Gradient ◽  
Fluid Velocity ◽  
Weather Conditions ◽  
Convective Zone ◽  
Heat Extraction ◽  
Solar Pond ◽  
Maximum Stability ◽  
Storage Zone ◽  
The Stability

The quality of the stability of the nonconvective zone of a salinity-gradient solar pond (SGSP) is investigated for an operating protocol in which the flushing procedure exactly compensates for evaporation losses from the solar pond and its associated evaporation pond. The mathematical model of the pond uses simplified, but accurate, constitutive expressions for the physical properties of aqueous sodium chloride. Also, realistic boundary conditions are used for the behaviors of the upper and lower convective zones (LCZs). The performance of a salinity-gradient solar pond is investigated in the context of the weather conditions at Makkah, Saudi Arabia, for several thickness of upper convective zone (UCZ) and operating temperature of the storage zone. Spectral collocation based on Chebyshev polynomials is used to assess the quality of the stability of the pond throughout the year in terms of the time scale for the restoration of disturbances in temperature, salinity, and fluid velocity underlying the critical eigenstate. The critical eigenvalue is found to be real and negative at all times of year indicating that the steady-state configuration of the pond is always stable, and suggesting that stationary instability would be the anticipated mechanism of instability. Annual profiles of surface temperature, salinity, and heat extraction are constructed for various combinations for the thickness of the upper convective zone and storage zone temperature.

The stability of electric energy markets

1999 ◽  
Vol 24 (3-4) ◽  
pp. 233-241 ◽  
Author(s):  
Fernando L. Alvarado
Keyword(s):  
Electric Energy ◽  
Energy Markets ◽  
The Stability

scholarly journals A Study on Electromagnetic Damper Control for Ball Screw Stages

2009 ◽  
Vol 75 (7) ◽  
pp. 887-891
Author(s):  
Susumu MAKINOUCHI ◽  
Kazuhiro HIRANO ◽  
Masahiro NAKADE ◽  
Shinji WAKUI
Keyword(s):  
Ball Screw ◽  
Damper Control ◽  
Electromagnetic Damper

scholarly journals Energy Dissipation-Based Method for Strength Determination of Rock under Uniaxial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
M. M. He ◽  
F. Pang ◽  
H. T. Wang ◽  
J. W. Zhu ◽  
Y. S. Chen
Keyword(s):  
Yield Strength ◽  
Uniaxial Compression ◽  
Peak Strength ◽  
Dissipated Energy ◽  
Compression Tests ◽  
Dissipation Energy ◽  
Evolution Characteristics ◽  
Deformation Properties ◽  
Energy Coefficient ◽  
The Stability

The energy conversion in rocks has an important significance for evaluation of the stability and safety of rock engineering. In this paper, some uniaxial compression tests for fifteen different rocks were performed. The evolution characteristics of the total energy, elastic energy, and dissipated energy for the fifteen rocks were studied. The dissipation energy coefficient was introduced to study the evolution characteristics of rock. The evolution of the dissipation energy coefficient for different rocks was investigated. The linear interrelations of the dissipation energy coefficients and the yield strength and peak strength were explored. The method was proposed to determine the strength of rock using the dissipation energy coefficients. The results show that the evolution of the dissipation energy coefficient exhibits significant deformation properties of rock. The dissipation energy coefficients linearly increase with the compaction strength, but decrease with the yield strength and peak strength. Moreover, the dissipation energy coefficient can be used to determine the rock burst proneness and crack propagation in rocks.

scholarly journals Modeling and stabilization of eccentric gravity machinery

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775178
Author(s):  
Wu-Sung Yao
Keyword(s):  
Control System ◽  
Digital Signal Processor ◽  
Repetitive Control ◽  
Electric Energy ◽  
Digital Signal ◽  
Control Performance ◽  
Velocity Control ◽  
Stability Performance ◽  
The Stability ◽  
And Control

In general, eccentric gravity machinery is a rotation mechanism with eccentric pendulum mechanism, which can be used to convert continuously kinetic energy generated by gravity energy to electric energy. However, a stable rotated velocity of the eccentric gravity machinery is difficult to be achieved only using gravity energy. In this article, a stable velocity control system applied to eccentric gravity machinery is proposed. The dynamic characteristic of eccentric gravity machinery is analyzed and its mathematical model is established, which is used to design the controller. A stable running velocity of the eccentric gravity machinery can be operated by the controlled servomotor. Due to disturbances being periodic, repetitive controller is installed to velocity control loop. The stability performance and control performance of the repetitive control system are discussed. The iterative algorithm of the repetitive control is executed by a digital signal processor TI TMS320C32 floating-point processor. Simulated and experimental results are reported to verify the performance of the proposed eccentric gravity machinery control system.

Delayed Reference Control Applied to Flexible Link Mechanisms: A Scheme for Effective and Stable Control

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Giovanni Boschetti ◽  
Dario Richiedei ◽  
Alberto Trevisani
Keyword(s):  
Vibration Control ◽  
Vibration Damping ◽  
Flexible Link ◽  
Damping Force ◽  
Flexible Links ◽  
Equivalent Damping ◽  
The Stability ◽  
Delayed Time ◽  
Reference Input ◽  
Stable Control

This paper extends the use of delayed reference controllers to the simultaneous motion and vibration control of flexible link mechanisms. Vibration damping is achieved by introducing an “equivalent damping force” into the system through the computation of a suitable delayed time. The delayed time, which is based on the measured vibrations, is then employed in the trajectory planner to set the reference input. The stability of the controller is discussed and its effectiveness is proved by applying it to a four-bar planar linkage with flexible links.

Mathematical Analysis of Stability of a Spinning Disk Under Rotating, Arbitrarily Large Damping Forces

1996 ◽  
Vol 118 (4) ◽  
pp. 657-662 ◽  
Author(s):  
F. Y. Huang ◽  
C. D. Mote
Keyword(s):  
Periodic Solution ◽  
Parameter Space ◽  
Perturbation Technique ◽  
Stability Boundary ◽  
Rotating Disk ◽  
Stable Region ◽  
Damping Force ◽  
Analysis Of Stability ◽  
The Stability ◽  
Nontrivial Periodic Solution

Stability of a rotating disk under rotating, arbitrarily large damping forces is investigated analytically. Points possibly residing on the stability boundary are located exactly in parameter space based on the criterion that at least one nontrivial periodic solution is necessary at every boundary point. A perturbation technique and the Galerkin method are used to predict whether these points of periodic solution reside on the stability boundary, and to identify the stable region in parameter space. A nontrivial periodic solution is shown to exist only when the damping does not generate forces with respect to that solution. Instability occurs when the wave speed of a mode in the uncoupled disk, when observed on the disk, is exceeded by the rotation speed of the damping force relative to the disk. The instability is independent of the magnitude of the force and the type of positive-definite damping operator in the applied region. For a single dashpot, nontrivial periodic solutions exist at the points where the uncoupled disk has repeated eigenfrequencies on a frame rotating with the dashpot and the dashpot neither damps nor energizes these modes substantially around these points.

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