scholarly journals Vibration Characteristics of an Industrial-Scale Flip-Flow Screen with Crank-Link Structure and Parameters Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Hongxi Li ◽  
Chusheng Liu ◽  
Ling Shen ◽  
Lala Zhao
Keyword(s):  
Rotational Speed ◽  
Kinematic Model ◽  
Maximum Error ◽  
Vibration Characteristics ◽  
Parameters Optimization ◽  
Industrial Scale ◽  
Efficient Operation ◽  
Link Structure ◽  
Screening Performance ◽  
Screen Surface

Flip-flow screens are increasingly used in the processing of fine wet coal. In this work, the vibration characteristics of an industrial-scale flip-flow screen with crank-link structure (FFSCLS) were investigated theoretically and experimentally. An improved kinematic model of FFSCLS was proposed and experiments are carried out to verify the reasonability. The effects of the key parameters of the eccentricity of the crankshaft, the rotational speed of the crankshaft, and the tension length of the screen surface on the vibration characteristics of the screen were investigated parametrically. The results show that the kinematic model can describe the vibration characteristics of screen perfectly with the maximum error between the theoretical and experimental results being within 6.96%. Moreover, the key parameters of the eccentricity of the crankshaft, the rotational speed of the crankshaft, and the tension length of the screen surface have significant effects on the vibrations of the screen body and screen surface. These parameters should be optimized to achieve maximum screening performance of the FFSCLS. This work should be useful for optimal design and efficient operation of the flip-flow screen.

scholarly journals Development of an Android OS Based Controller of a Double Motor Propulsion System for Connected Electric Vehicles and Communication Delays Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Pedro Daniel Urbina Coronado ◽  
Horacio Ahuett-Garza ◽  
Vishnu-Baba Sundaresan ◽  
Ruben Morales-Menendez
Keyword(s):  
Rotational Speed ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Autonomous Driving ◽  
Maximum Error ◽  
Local Area ◽  
Propulsion System ◽  
Area Network ◽  
Market Demand ◽  
Real Time Control

Developments of technologies that facilitate vehicle connectivity represent a market demand. In particular,mobile device(MD) technology provides advanced user interface, customization, and upgradability characteristics that can facilitate connectivity and possibly aid in the goal of autonomous driving. This work explores the use of a MD in the control system of a conceptualelectric vehicle(EV). While the use of MD for real-time control and monitoring has been reported, proper consideration has not been given to delays in data flow and their effects on system performance. The motor of a novel propulsion system for an EV was conditioned to be controlled in a wireless local area network by an ecosystem that includes a MD and an electronic board. An intended accelerator signal is predefined and sent to the motor and rotational speed values produced in the motor are sent back to the MD. Sample periods in which the communication really occurs are registered. Delays in the sample periods and produced errors in the accelerator and rotational speed signals are presented and analyzed. Maximum delays found in communications were of 0.2 s, while the maximum error produced in the accelerator signal was of 3.54%. Delays are also simulated, with a response that is similar to the behavior observed in the experiments.

Parameters optimization in FSW of polypropylene based on RSM

2015 ◽  
Vol 11 (1) ◽  
pp. 32-42 ◽  
Author(s):  
K Panneerselvam ◽  
Kasirajan Lenin
Keyword(s):  
Process Parameters ◽  
Rotational Speed ◽  
Optimization Techniques ◽  
Parameters Optimization ◽  
Tool Rotational Speed ◽  
Content Type ◽  
Friction Stir ◽  
Optimization Of Process Parameters ◽  
Output Characteristics ◽  
Tool Pin

Purpose – The purpose of this paper is to weld polypropylene (PP) material by friction stir welding (FSW) process. The input process parameters considered were: tool pin profile, feed rate and tool rotational speed and the process output characteristics were tensile strength, Shore-D hardness, Rockwell hardness, Izod strength, Charpy strength and nugget area. Design/methodology/approach – Optimization of process parameters were carried out based on response surface methodology (RSM) and significant parameters were obtained by performing analysis of variance (ANOVA). Findings – The optimized results were the threaded pin profile for feed of 60 mm/min and tool rotational speed of 1,500 rpm. A confirmation test was carried out to verify the optimized results. Originality/value – In this paper, the process parameters were optimized based on RSM. This is newly adopted optimization techniques in the FSW process of PP materials and also it gives better results.

Relative Torsional Vibration Analysis for Crankshaft

2001 ◽  
Author(s):  
Jouji Kimura ◽  
Satoshi Shibata ◽  
Atsushi Ebe
Keyword(s):  
Torsional Vibration ◽  
Pressure Fluctuation ◽  
Rotational Speed ◽  
Vibration Analysis ◽  
Vibration Characteristics ◽  
Cylinder Pressure

Abstract Crankshaft torsional vibration characteristics have been studied, more often based on the results of measurement at a pulley, rather than in relation to a pulley. The results of the measurement at a pulley, however, include crankshaft torsion assuming that a crankshaft is elastic, as well as rotational speed changes due to cylinder pressure fluctuation assuming that a crankshaft is rigid. The authors recommend that relative torsional amplitude should be used in evaluating torsional vibration characteristics, rather than torsional amplitude at a pulley.

Vibration Characteristics of Rotating Thin Disks—Part II: Analytical Predictions

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
Ramin M. H. Khorasany ◽  
Stanley G. Hutton
Keyword(s):  
Frequency Response ◽  
Rotational Speed ◽  
Plate Theory ◽  
Lateral Displacement ◽  
Travelling Waves ◽  
Stationary Wave ◽  
Companion Paper ◽  
Vibration Characteristics ◽  
Experimental Results ◽  
Thin Disks

This paper is concerned with the geometric nonlinear analysis of the lateral displacement of thin rotating disks when subjected to a space fixed stationary force. Of particular interest is the development of the stationary wave and the effect of this wave on the frequency response of the disk as a function of its rotational speed. The predictions of this analysis are compared with experimental data obtained in a companion paper (Khorasany and Hutton, “Vibration Characteristics of Rotating Thin Disks—Part I: Experimental Results,” ASME J. Appl. Mech., 79(4), p. 041006). The governing equations are based on Von Kármán plate theory. A Galerkin solution of the governing non linear equations is developed. The eigenfunctions derived from the linear analysis of a stationary disk are used as approximations to the spatial response of the disk, and the eigenfunctions of the biharmonic equation as approximations for the stress function. Using the developed solution, the equilibrium configuration of the disk under the application of a space fixed force is found. In order to facilitate the prediction of the frequency response, as a function of disk rotational speed, the governing nonlinear equations are linearized around the equilibrium solution. The linearized equations are then used to find the eigenvalues of the spinning disk under the application of a space fixed force. The effect of different levels of nonlinearity on the disk frequencies is studied and compared with experimental results. The analysis is shown to produce an accurate representation of the measured response. Of particular interest is the disk response at speeds close to and above the linear critical speed. In this region, both the analysis and the experimental results display frequency “lock-in” behavior in which the frequency of backward travelling waves becomes constant for supercritical speeds. No speed exists for which backward travelling waves have zero frequency. Thus, critical speeds do not exist in the presence of geometric nonlinearities.

A Soft-Robotic End-Effector for Independently Actuating Endoscopic Catheters

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
K. P. Ashwin ◽  
Ashitava Ghosal
Keyword(s):  
Ex Vivo ◽  
Kinematic Model ◽  
Maximum Error ◽  
Artificial Muscles ◽  
Design Development ◽  
End Effector ◽  
Kinematics Model ◽  
Catheter Tip ◽  
Soft Actuators ◽  
Forward Kinematic

Abstract This paper deals with the design, development, modeling, and experimental validation of a prototype endoscopic attachment that can be actuated independently by soft actuators to position an endoscopic catheter tip to a desired location. The soft actuators are miniaturized pneumatic artificial muscles (MPAMs), and by applying 137–827 kPa pressure to one or more MPAMs, the tip of the endoscopic catheter can be positioned in an approximately hemispherical region of 45 mm radius. An optimization-based forward kinematic model to predict the profile of the actuated end-effector is developed. Experiments conducted on the prototype show that the kinematics model can predict the deformation profile of the end-effector with a maximum error of 2 mm. An inverse-kinematics model to estimate the pressure required in the MPAMs to position the tip of the catheter at a specified point is also developed. The pressures in the MPAMs are controlled using an ATmel ATMega 2560 micro-controller with the inputs generated with a thumb-stick to show that real-time actuation is possible. Finally, ex-vivo experiments were conducted to show that the developed prototype end-effector can be successfully used to independently actuate endoscopic catheters.

Study on the Model of a Single-Point Diamond Fly Cutting Machine Tool at Different Rotational Speed Based on Transfer Matrix Method for Multibody Systems

2018 ◽  
Author(s):  
Yu Chang ◽  
Jianguo Ding ◽  
Hui Zhuang ◽  
Peng Chen ◽  
Wei Wei ◽  
...  
Keyword(s):  
Machine Tool ◽  
Transfer Matrix Method ◽  
Rotational Speed ◽  
Multibody Systems ◽  
Natural Vibration ◽  
Single Point ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Cutting Machine ◽  
Natural Vibration Characteristics

Natural vibration characteristics are important factors affecting the processing quality for an ultra-precision machine tool. The rapid and accurate calculation method for solving natural vibration characteristics has a significance in machine tool dynamics design. By applying the transfer matrix method for multibody systems (MSTMM), the dynamics model of a single-point diamond fly cutting machine tool is established and the rapid computation of natural vibration characteristics at different rotational speed is completed. The results calculated by MSTMM is compared with those by finite element software ABAQUS, the error between the first ten frequencies calculated by MSTMM and ABAQUS is less than 5.68%. However, as the rotational speed increases, the first eight frequencies and mode shapes have no obvious change, while the 9th and 10th modal change significantly. The mode shapes of 9th and 10th orders are vacillation of the spindle. The results show that the rotation of aerostatic spindle has significant effect on the spindle system and little effect on the other parts.

scholarly journals Discrete Element Simulation of the Effect of Roller-Spreading Parameters on Powder-Bed Density in Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2285
Author(s):  
Jiangtao Zhang ◽  
Yuanqiang Tan ◽  
Tao Bao ◽  
Yangli Xu ◽  
Xiangwu Xiao ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Layer Thickness ◽  
Rotational Speed ◽  
High Performance ◽  
Ceramic Powder ◽  
Discrete Element ◽  
Parameters Optimization ◽  
Powder Layer ◽  
Translational Velocity ◽  
Powder Bed

The powder-bed with uniform and high density that determined by the spreading process parameters is the key factor for fabricating high performance parts in Additive Manufacturing (AM) process. In this work, Discrete Element Method (DEM) was deployed in order to simulate Al2O3 ceramic powder roller-spreading. The effects of roller-spreading parameters include translational velocity Vs, roller’s rotational speed ω, roller’s diameter D, and powder layer thickness H on powder-bed density were analyzed. The results show that the increased translational velocity of roller leads to poor powder-bed density. However, the larger roller’s diameter will improve powder-bed density. Moreover, the roller’s rotational speed has little effect on powder-bed density. Layer thickness is the most significant influencing factor on powder-bed density. When layer thickness is 50 μm, most of particles are pushed out of the build platform forming a lot of voids. However, when the layer thickness is greater than 150 μm, the powder-bed becomes more uniform and denser. This work can provide a reliable basis for roller-spreading parameters optimization.

scholarly journals Vibration Characteristics of a Mistuned Bladed Disk considering the Effect of Coriolis Forces

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Xuanen Kan ◽  
Bo Zhao
Keyword(s):  
Coriolis Force ◽  
Rotational Speed ◽  
Natural Frequencies ◽  
Forced Response ◽  
Vibration Characteristics ◽  
Magnification Factor ◽  
Coriolis Forces ◽  
Rotating Speed ◽  
Bladed Disk ◽  
Coriolis Effects

To investigate the influence of Coriolis force on vibration characteristics of mistuned bladed disk, a bladed disk with 22 blades is employed and the effects of different rotational speeds and excitation engine orders on the maximum forced response are discussed considering the effects of Coriolis forces. The results show that if there are frequency veering regions, the largest split of double natural frequencies of each modal family considering the effects of Coriolis forces appears at frequency veering region. In addition, the amplitude magnification factor considering the Coriolis effects is increased by 1.02% compared to the system without considering the Coriolis effects as the rotating speed is 3000 rpm, while the amplitude magnification factor is increased by 2.76% as the rotating speed is 10000 rpm. The results indicate that the amplitude magnification factor may be moderately enhanced with the increasing of rotating speed. Moreover, the position of the maximum forced response of bladed disk may shift from one blade to another with the increasing of the rotational speed, when the effects of Coriolis forces are considered.

scholarly journals Rotational Speed Measurement Based on LC Wireless Sensors

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8055
Author(s):  
Yi Zhou ◽  
Lei Dong ◽  
Chi Zhang ◽  
Lifeng Wang ◽  
Qingan Huang
Keyword(s):  
Rotational Speed ◽  
Wireless Sensors ◽  
Rotation Speed ◽  
Maximum Error ◽  
Design System ◽  
Synchronous Detection ◽  
Sensing System ◽  
System A ◽  
Detection Circuit ◽  
Lc Tank

This article presents a method for detecting rotational speed by LC (inductor-capacitor) wireless sensors. The sensing system consists of two identical LC resonant tanks. One is mounted on the rotating part and the other, as a readout circuit, is placed right above the rotating part. When the inductor on the rotating part is coaxially aligned with the readout inductor during rotation, the mutual coupling between them reaches the maximum, resulting in a peak amplitude induced at the readout LC tank. The period of the readout signal corresponds to the rotation speed. ADS (Advanced Design System) software was used to simulate and optimize the sensing system. A synchronous detection circuit was designed. The rotational speed of an electric was measured to validate this method experimentally, and the results indicated that the maximum error of the rotation speed from 16 rps to 41 rps was 0.279 rps.

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