An Efficient Finite Element Procedure for Analysis of High-Speed Spiral Groove Gas Face Seals

2000 ◽  
Vol 123 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Marco Tulio C. Faria
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Dynamic Performance ◽  
Dynamic Force ◽  
Spiral Groove ◽  
Weighted Residual Method ◽  
New Class ◽  
High Speeds ◽  
Face Seals ◽  
Finite Element Procedure

An efficient and accurate finite element procedure is specially devised to analyze the performance of gas-lubricated spiral groove face seals operating at high speeds. The procedure is based on the Galerkin weighted residual method with a new class of high-order shape functions, which are derived from an approximate solution to the nonlinear Reynolds equation within an element. Static and dynamic performance characteristics, such as seal opening force, flow leakage and frequency-dependent dynamic force coefficients, are determined to study the effects of high speeds on the behavior of spiral groove gas face seals.

scholarly journals Suspending force modeling based on nonlinear acoustics and high-speed running experiments for an ultrasonic journal bearing

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402094047
Author(s):  
He Li ◽  
Yu Wang ◽  
Deen Bai ◽  
Fuyan Lyu ◽  
Kuidong Gao ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
High Speed ◽  
Acoustic Radiation ◽  
Dynamic Performance ◽  
Force Model ◽  
Trajectory Data ◽  
Running Performance ◽  
High Speeds ◽  
Radiation Theory

As a kind of promising noncontact bearings, ultrasonic bearings actuated by smart materials such as lead zirconate titanate ceramics show a good application prospect in high-speed machines and precision-measuring devices. The suspending force is one of the most important parameters that play a dominated role on the bearing’s static and dynamic performance. A suspending force model based on acoustic radiation theory for cylindrical object near sound source is built to predict the radial carrying capacity of an ultrasonic bearing actuated by three piezoelectric transducers. To validate the model, an ultrasonic bearing prototype is developed and a testing system is established. For observing the bearing’s dynamic running performance at high speeds, the bearing’s running experiment is carried out and the rotor center’s trajectory data and frequency spectrum are acquired to analyze the bearing’s dynamic characteristics at high speeds. The suspending force model and running performance experiments will contribute to the design, detection, and test of this type of bearings.

DYNAMIC PERFORMANCE OF POST-BUCKLED PRECOMPRESSED PIEZOELECTRIC ACTUATOR ELEMENTS

2012 ◽  
Vol 12 (05) ◽  
pp. 1250042 ◽  
Author(s):  
GEORGIOS GIANNOPOULOS ◽  
MARK GROEN ◽  
ROELOF VOS ◽  
RON BARRETT
Keyword(s):  
Finite Element ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Past Research ◽  
Element Model ◽  
Axial Loads ◽  
New Class ◽  
Axial Forces ◽  
Bimorph Actuators ◽  
Full Force

Post-buckled precompressed (PBP) piezoelectric elements have recently been used to enable a new class of actuators that are able to provide far higher deflections compared to the traditional bimorph piezoelectric actuators while maintaining full force and moment generating capabilities. Past research has proven that PBP actuators are capable of generating deflections three times higher than conventional bimorph actuators. In this paper, this work has been extended to the dynamic response realm and the performance of PBP actuators is investigated under various axial loads, at various actuation frequencies. Both analytical and finite element models have been developed in order to evaluate the performance of the actuator regarding the natural frequency shift under increased axial loads. Experimental verification has shown that the overall damping ratio of the structure is a function of the axial forces. Values derived from experiments have been used in the Finite Element model to predict the displacement output, phase angle shifting and end rotation. Numerical and analytical results correlate very well with the experiments and thus give credit to the formulation presented in this work.

A dynamic modeling approach for the winding spindle during start-up with a coupled flexible support system

2019 ◽  
Vol 90 (7-8) ◽  
pp. 757-775
Author(s):  
Yongxing Wang ◽  
Lijun Zhang ◽  
Xi Hou ◽  
Jiang Yan ◽  
Shujia Li ◽  
...  
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Dynamic Performance ◽  
Beam Theory ◽  
Filament Winding ◽  
Heavy Load ◽  
Frequency Dependent ◽  
Spindle System ◽  
Start Up ◽  
Deep Groove

A polyester filament winding spindle is the most complex winding rotor system, due to its high speed, heavy load, and frequency-dependent parameters; furthermore, the spindle's rotating speed constantly changes and it is continually crossing the critical speed points. This paper presents an approach to establish the finite element model of the winding spindle to predict its dynamic behavior characteristics during start-up. Firstly, three finite element models of the discrete single component were developed based on the Timoshenko beam theory. The bending, transverse shear effect, and gyroscopic moment were considered in these models. The flexible supporting system, which consists of a deep groove ball bearing and several rubber O-rings, is simplified by a nonlinear spring and damper. Its frequency-dependent dynamic supporting parameters are identified by experiment. Secondly, a fully dynamic model of the polyester winding spindle system, which consists of the cantilever supporting arm, shaft, and sleeve, as well as the flexible and rigid coupling elements, was established. Thirdly, the Newmark method was used to develop a program for solving the dynamic equations of the spindle system in MATLAB®. Based on the model of the spindle system and the computation program, the effects of the supporting stiffness, damping, and start-up time on the spindle's unbalanced response were investigated. The results indicate that the model of the spindle system presented in this paper is suitable for the prediction of the dynamic performance during its start-up.

scholarly journals Influence of Floating Ring Seal Working Condition Parameters on the Dynamic Characteristics of Transient Gas Film

2021 ◽  
Vol 2108 (1) ◽  
pp. 012087
Author(s):  
Lishan Xu ◽  
Weizheng Zhang ◽  
Junjie Lu ◽  
Zhu Liu
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Spiral Groove ◽  
Low Leakage ◽  
Ring Seal ◽  
Stiffness And Damping Coefficient ◽  
Small Perturbation Method ◽  
Stiffness And Damping

Abstract The high requirements for sealing performance in high-speed rotating machinery has led to the design of floating seal with annular spiral groove that offer the advantages of low leakage and extended stability. However, efforts to model the dynamic performance of these floating seal have suffered from the great complexity of the flow field. The present work addresses this issue by establishing a transient Reynolds formulation of a floating seal with annular spiral groove in a rotating coordinate system based on the small perturbation method. In addition, the influence of radial eccentricity and film thickness on the solution divergence and calculation accuracy is calculated. The dynamic stiffness and dynamic damping matrixes are built. Then the variation rules of the dynamic stiffness and damping coefficient of the gas film with structure and working conditions are investigated in detail. The results show that the floating ring seal is more suitable for the service conditions of small film thickness, low pressure, high speed and large eccentricity. Accordingly, the results obtained lay a theoretical foundation for evaluating real-world applications of floating ring seal.

Finite Element Analysis and Optimization of Structure for Large Blanking Machine Equipment during High-Speed Blanking

2011 ◽  
Vol 697-698 ◽  
pp. 176-181
Author(s):  
Shu Bo Xu ◽  
K.K. Sun ◽  
Cai Nian Jing ◽  
Guo Cheng Ren
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Optimal Design ◽  
High Speed ◽  
Dynamic Performance ◽  
Design Stage ◽  
Beam Structure ◽  
Element Analysis ◽  
Blanking Process ◽  
Dynamic Performance Analysis

This paper reviews the background and significance to investigate the high-speed speed blanking process modeling simulation and optimization of large blanking machine equipment for CNC uncoiling, leveling and shearing line. And a powerful tool has been providing to of heavy machinery optimal design specifications. The finite element model of beam structure has been established by using a three-dimensional modeling software UG NX4.0 CAD and finite element analysis software ANSYS. Then the static and dynamic characteristics results of the whole beam structure have been simulated. On the basis of analysis results, the optimal static and dynamic performance of square cross-section of the beam structure has been obtained. Drawings at the design stage of large blanking machine equipment for NC uncoiling, leveling and shearing line, the use of finite element theory and modal analysis theory, the structure of the blanking machine static and dynamic performance analysis and prediction using optimal design method for optimization, the new machine to improve job performance, improve processing accuracy, shorten the development cycle and enhance the competitiveness of products is very important.

Effect of Frequency Excitation on Force Coefficients of Spiral Groove Gas Seals

1999 ◽  
Vol 121 (4) ◽  
pp. 853-861 ◽  
Author(s):  
Nicole Zirkelback ◽  
Luis San Andre´s
Keyword(s):  
Finite Element ◽  
Compressible Fluid ◽  
Fluid Model ◽  
Dynamic Performance ◽  
Excitation Frequency ◽  
Spiral Groove ◽  
Thrust Bearings ◽  
Force Coefficients ◽  
Frequency Excitation ◽  
Gas Seals

An analysis for compressible fluid spiral groove thrust bearings (SGTBs) and face seals (SGFSs) is presented. Zeroth- and first-order equations rendering the static and dynamic performance of SGFSs, respectively, are solved using the finite element method with a successive approximation scheme. Comparison of the present isothermal compressible fluid model for static and dynamic SGTB and SGFS performance validates previous narrow groove theory, finite difference, and finite element analyses. A discussion follows to indicate the importance of using a small number of grooves to prevent instabilities from negative damping in SGTBs and SGFSs when pressurization is lost. Force coefficients are shown to reach asymptotic limits as the axial excitation frequency increases.

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