scholarly journals Dynamics Analysis of Unbalanced Motorized Spindles Supported on Ball Bearings

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Junfeng Liu ◽  
Tao Lai ◽  
Xiaoan Chen
Keyword(s):  
High Speed ◽  
Magnetic Force ◽  
Numerical Solutions ◽  
Dynamic Properties ◽  
Lyapunov Stability Theory ◽  
Force Model ◽  
Proposed Model ◽  
Dynamic Operating ◽  
Motorized Spindles ◽  
Good Agreement

This paper presents an improved dynamic model for unbalanced high speed motorized spindles. The proposed model includes a Hertz contact force model which takes into the internal clearance and an unbalanced electromagnetic force model based on the energy of the air magnetic field. The nonlinear characteristic of the model is analysed by Lyapunov stability theory and numerical analysis to study the dynamic properties of the spindle system. Finally, a dynamic operating test is carried out on a DX100A-24000/20-type motorized spindle. The good agreement between the numerical solutions and the experimental data indicates that the proposed model is capable of accurately predicting the dynamic properties of motorized spindles. The influence of the unbalanced magnetic force on the system is studied, and the sensitivities of the system parameters to the critical speed of the system are obtained. These conclusions are useful for the dynamic design of high speed motorized spindles.

scholarly journals Thermo-mechanical behavior analysis of motorized spindle based on a coupled model

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774714 ◽  
Author(s):  
Junfeng Liu ◽  
Peng Zhang
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Coupled Model ◽  
Solution Procedure ◽  
Motorized Spindle ◽  
Proposed Model ◽  
Motorized Spindles ◽  
Rotor Dynamic

This article presents a thermo-mechanical coupled dynamic model for high-speed motorized spindles. The proposed model includes an angular ball bearing model, a thermal model, and a rotor dynamic model. The coupling relationship among these submodels is analyzed, and a solution procedure for the integrated model is designed. Based on the proposed model and solution procedure, the dynamic behaviors of the spindle system and the effects of the thermal displacement of the system on the behaviors are quantificationally discussed. Finally, an integrated dynamic test is carried out on a D62D24A-type motorized spindle, and the good agreement between the mathematical results and the experimental data indicates that the proposed model is capable of accurately predicting the dynamic properties of motorized spindles, and the accuracy of the model is improved when considering the thermo-mechanical coupled factor. The conclusions are useful for the dynamic design and the thermal compensation control of high-speed motorized spindles.

Pressure Drop of Fully-Developed, Laminar Flow in Microchannels of Arbitrary Cross-Section

2006 ◽  
Vol 128 (5) ◽  
pp. 1036-1044 ◽  
Author(s):  
M. Bahrami ◽  
M. M. Yovanovich ◽  
J. R. Culham
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Cross Section ◽  
Numerical Solutions ◽  
Approximate Model ◽  
Arbitrary Cross Section ◽  
Geometrical Parameters ◽  
Polar Moment ◽  
Proposed Model ◽  
Good Agreement

The pressure drop of fully developed, laminar, incompressible flow in smooth mini- and microchannels of arbitrary cross-section is investigated. A compact approximate model is proposed that predicts the pressure drop for a wide variety of shapes. The model is only a function of geometrical parameters of the cross-section, i.e., area, perimeter, and polar moment of inertia. The proposed model is compared with analytical and numerical solutions for several shapes. Also, the comparison of the model with experimental data, collected by several researchers, shows good agreement.

EFFICIENT DELAY AND CROSSTALK ESTIMATION MODELS FOR CURRENT-MODE HIGH SPEED INTERCONNECTS UNDER RAMP INPUT

2014 ◽  
Vol 23 (06) ◽  
pp. 1450082 ◽  
Author(s):  
M. KAVICHARAN ◽  
N. S. MURTHY ◽  
N. BHEEMA RAO
Keyword(s):  
Transfer Function ◽  
High Speed ◽  
Large Scale ◽  
Current Mode ◽  
Element Model ◽  
Maximum Error ◽  
Vlsi Circuits ◽  
Worst Case ◽  
Proposed Model ◽  
Good Agreement

In this paper, closed-form models for the computation of finite ramp responses of current-mode resistance inductance capacitance (RLC) interconnects in VLSI circuits are presented. These models are based on extended Eudes model and Scaling and Squaring algorithm which allow numerical estimation of delay in lossy very large scale integration (VLSI) interconnects. The existing Eudes model for interconnect transfer function approximation is extended to higher-order and then Scaling and Squaring method is applied for further improving the accuracy of delay estimation. With the equivalent lossy interconnect transfer function, finite ramp responses are obtained and line delay is estimated for various line lengths, per unit inductances and load capacitances. The estimated 50% delay values are compared with HSPICE W-element model. The worst case errors observed in the estimated delay values are 14.3% for Eudes model and 2% for extended Eudes model while the proposed Scaling and Squaring based model with 1% error is in very good agreement with HSPICE for line lengths 0.1–0.5 cm. The estimated crosstalk induced delay values of proposed model maximum error percentage is nearly half of the extended Eudes model. For both single and three coupled interconnect lines, the proposed model is in good agreement with HSPICE.

High Speed Rail Short Bridge-Track-Train Interaction Based on the Decoupled Equations of Motion in the Finite Element Domain

2016 ◽  
Author(s):  
Said I. Nour ◽  
Mohsen A. Issa
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Numerical Solutions ◽  
Equations Of Motion ◽  
Rotational Inertia ◽  
Force Model ◽  
Inertia Effects ◽  
Contact Points ◽  
Short Span ◽  
Track Bridge

The interaction between the train, track, and bridge was considered as an interaction between two decoupled subsystems. A first subsystem consisted of the train vehicle simulated as a four-wheelset mass-spring-damper system having two layers of suspensions and ten degrees of freedom. A second subsystem consisted of the track-bridge system assumed to be a top rail beam and a bottom bridge beam coupled by continuous springs and dampers representing the elastic properties of the trackbed smeared over the spacing of the railway ties. The bridge supports were assumed to be rigid or flexible. The equations of motion of a finite element form were derived for each subsystem independently by means of the Newton’s second law. The dynamic interaction between the moving vehicle of the first subsystem and the stationary underlying track-bridge structure of the second subsystem was established by means of a no-separation constraint equation in the contact points between the wheels and the rails. The proposed two-dimensional analysis was intended to accurately describe the vertical behavior of short span bridges subjected to high-frequency excitations due to the passage of high speed trains; therefore, shear deformations, rotational inertia effects, and consistent mass matrices were adopted in the mathematical model. Numerical solutions of the decoupled equations of motion for both subsystems were obtained with the step-by-step direct integration in the time domain using HHT alpha method with a special scheme in the contact interface. The solution accuracy of the proposed method was validated against responses obtained from a semi-analytical method of a train car travelling over a simply supported bridge. The practical engineering application was demonstrated with a case study investigating effects of key parameters in the behavior of a ballasted short span railway bridge. Compared with the moving force model, results showed that for bridges with rigid supports both the vehicle interaction and trackbed produce lower peak responses at resonance speeds with the latter being more significant. However an increase in support flexibility had a greater impact across all speeds in increasing the bridge responses.

Comparative Study on 2A70 Aluminum Alloy High-Speed Milling Cutting Force Model

2011 ◽  
Vol 188 ◽  
pp. 254-257
Author(s):  
Xue Hui Wang ◽  
Ming Jun Feng ◽  
Can Zhao
Keyword(s):  
Aluminum Alloy ◽  
Linear Model ◽  
Nonlinear Model ◽  
High Speed ◽  
Tool Path ◽  
Force Model ◽  
High Speed Milling ◽  
Set Up ◽  
Good Agreement

The mechanical properties of flat end mill is analyzed the high-speed milling, the linear model for milling force is established. And the 2A70 aluminum alloy four-factor four-level orthogonal milling tests are carried out, the nonlinear model of milling is set up by using regression analysis method. The comparative analysis is made between the linear model and nonlinear model, whose results show that the two models have good agreement on the value and trend of change, which is the basis of the follow-up tool path optimization, fault diagnosis and so on.

Prediction of Fiber Die Coating Thickness

2006 ◽  
Vol 920 ◽  
Author(s):  
An Yang ◽  
XiaoMing Tao ◽  
XiaoYin Chen
Keyword(s):  
Coating Thickness ◽  
High Speed ◽  
Fiber Surface ◽  
External Pressure ◽  
Viscous Force ◽  
Coating Process ◽  
Fiber Coating ◽  
Coating Flow ◽  
Proposed Model ◽  
Good Agreement

AbstractFiber coating is an effective way to impart smartness to a fiber. Die coating is a process that utilizes a die to control the thickness and concentricity of the coating layer. In the present work the die coating mechanism is studied numerically. A mathematical model for the fiber coating thickness has been developed. Compared with the previous work, the proposed model considers the effect of gravity force to get the general solution. The shear rate acting on the fiber surface is proportional to the fiber draw speed in an unpressurized applicator and can be minimized in a pressurized applicator through the applied external pressure. A serials of experiments using open-cup and pressurized applicators have been designed and conducted to measure simultaneously the coating speed and coating thickness in the coating process. It was found that the gravity may be an important driving force for the coating flow when the drawing velocity is small and the viscous force decreases, but may be relatively insignificant for high speed coating process. The calculated results were compared with the experimental data and a good agreement was obtained.

scholarly journals Numerical solutions of fuzzy equal width models via generalized fuzzy fractional derivative operators

2021 ◽  
Vol 7 (2) ◽  
pp. 2695-2728
Author(s):  
Rehana Ashraf ◽  
◽  
Saima Rashid ◽  
Fahd Jarad ◽  
Ali Althobaiti ◽  
...  
Keyword(s):  
Numerical Solutions ◽  
Initial Conditions ◽  
Transform Method ◽  
Homotopy Perturbation ◽  
Proposed Model ◽  
Wide Range ◽  
Fractional Models ◽  
The Subject ◽  
Good Agreement ◽  
Numerical Approaches

<abstract><p>The Shehu homotopy perturbation transform method (SHPTM) via fuzziness, which combines the homotopy perturbation method and the Shehu transform, is the subject of this article. With the assistance of fuzzy fractional Caputo and Atangana-Baleanu derivatives operators, the proposed methodology is designed to illustrate the reliability by finding fuzzy fractional equal width (EW), modified equal width (MEW) and variants of modified equal width (VMEW) models with fuzzy initial conditions (ICs). In cold plasma, the proposed model is vital for generating hydro-magnetic waves. We investigated SHPTM's potential to investigate fractional nonlinear systems and demonstrated its superiority over other numerical approaches that are accessible. Another significant aspect of this research is to look at two significant fuzzy fractional models with differing nonlinearities considering fuzzy set theory. Evaluating various implementations verifies the method's impact, capabilities, and practicality. The level impacts of the parameter $ \hbar $ and fractional order are graphically and quantitatively presented, demonstrating good agreement between the fuzzy approximate upper and lower bound solutions. The findings are numerically examined to crisp solutions and those produced by other approaches, demonstrating that the proposed method is a handy and astonishingly efficient instrument for solving a wide range of physics and engineering problems.</p></abstract>

Analysis of Super-High Speed Point Grinding Forces

2010 ◽  
Vol 126-128 ◽  
pp. 47-51
Author(s):  
Ya Dong Gong ◽  
Jian Qiu ◽  
Yue Ming Liu ◽  
Jun Cheng
Keyword(s):  
High Speed ◽  
High Surface ◽  
Experimental Tests ◽  
Equivalent Diameter ◽  
Force Model ◽  
Grinding Forces ◽  
High Surface Quality ◽  
Swivel Angle ◽  
Model Point ◽  
Good Agreement

Super high-speed point grinding is a good performance grinding with high surface quality due to its low force. To model point grinding forces including swivel angle formed by tilting wheel to the horizontal workpiece axis seems necessary. In this research, a point grinding force model was present, and the point grinding forces are influenced by factors such as grinding depth, wheel velocity, swivel angle as well as equivalent diameter. And then some experimental tests are carried out. It is found that the experimental data was in good agreement with theoretical model.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

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