Numerical Model of a Reciprocating Hydraulic Rod Seal

2006 ◽  
Vol 129 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Richard F. Salant ◽  
Nicholas Maser ◽  
Bo Yang
Keyword(s):  
Numerical Model ◽  
Fluid Mechanics ◽  
Contact Mechanics ◽  
Thickness Distribution ◽  
Computational Procedure ◽  
Element Analysis ◽  
Pressure Distributions ◽  
Influence Coefficients ◽  
Mechanics Analysis ◽  
Deformation Mechanics

A numerical model of an elastomeric reciprocating hydraulic rod seal has been constructed. The model consists of coupled fluid mechanics, deformation mechanics, and contact mechanics analyses, with an iterative computational procedure. The fluid mechanics analysis consists of the solution of the Reynolds equation, using flow factors to account for surface roughness. Deformation of the seal is computed through the use of influence coefficients, obtained from an off-line finite element analysis. The contact mechanics analysis uses the Greenwood and Williamson model. The seal model is used to predict leakage rate, friction force, fluid and contact pressure distributions, and film thickness distribution. Results for a typical seal show that the seal operates with mixed lubrication, and the seal roughness plays an important role in determining whether or not the seal leaks.

Numerical Model of a Tandem Reciprocating Hydraulic Rod Seal

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Bo Yang ◽  
Richard F. Salant
Keyword(s):  
Steady State ◽  
Numerical Model ◽  
Fluid Mechanics ◽  
Contact Mechanics ◽  
Computational Procedure ◽  
Stroke Length ◽  
Lip Seal ◽  
Through Flow ◽  
Deformation Mechanics

A numerical model of a tandem reciprocating hydraulic rod seal, consisting of two elastomeric U cup seals, has been constructed. It is applicable to cases in which the stroke length is significantly larger than the seal width. The model consists of coupled steady state fluid mechanics, deformation mechanics, and contact mechanics analyses, with an iterative computational procedure. The behaviors of the two seals are coupled through the pressure∕density in the interseal region and through flow continuity. Results for a typical tandem seal are compared to those of a single seal and a double lip seal.

Numerical Model of a Tandem Reciprocating Hydraulic Rod Seal

2007 ◽  
Author(s):  
Bo Yang ◽  
Richard F. Salant
Keyword(s):  
Steady State ◽  
Numerical Model ◽  
Fluid Mechanics ◽  
Contact Mechanics ◽  
Computational Procedure ◽  
Lip Seal ◽  
Through Flow ◽  
Deformation Mechanics

A numerical model of a tandem reciprocating hydraulic rod seal, consisting of two elastomeric U cup seals, has been constructed. The model consists of coupled steady state fluid mechanics, deformation mechanics and contact mechanics analyses, with an iterative computational procedure. The behaviors of the two seals are coupled through the pressure/density in the inter-seal region and through flow continuity. Results for a typical tandem seal are compared with those of a single seal and a double lip seal.

Soft EHL Simulations of U-Cup and Step Hydraulic Rod Seals

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Bo Yang ◽  
Richard F. Salant
Keyword(s):  
Steady State ◽  
Fluid Mechanics ◽  
Contact Mechanics ◽  
Critical Speed ◽  
Thermal Analyses ◽  
Elastohydrodynamic Lubrication ◽  
Computational Procedure ◽  
Stroke Length ◽  
Deformation Mechanics ◽  
Rod Seals

A numerical soft elastohydrodynamic lubrication model of a reciprocating hydraulic seal has been used to simulate the performance of a U-cup seal and a step seal in a conventional actuator. The model consists of coupled steady state fluid mechanics, deformation mechanics, contact mechanics, and thermal analyses, with an iterative computational procedure. The results indicate that for a given seal roughness and stroke length there is a critical rod speed above which the seal will not leak. The critical speed is dependent on both seal roughness and sealed pressure.

Soft EHL Analysis of a Reciprocating Hydraulic Step Seal

2008 ◽  
Author(s):  
Bo Yang ◽  
Richard F. Salant
Keyword(s):  
Steady State ◽  
Fluid Mechanics ◽  
Contact Mechanics ◽  
Thermal Analyses ◽  
Elastohydrodynamic Lubrication ◽  
Computational Procedure ◽  
Deformation Mechanics

A numerical soft EHL (elastohydrodynamic lubrication) model of a reciprocating hydraulic step seal has been used to analyze seal performance. The model consists of coupled steady state fluid mechanics, deformation mechanics, contact mechanics and thermal analyses, with an iterative computational procedure. Results for a typical step seal are compared with those of a double lip U-cup seal.

Visco-Elastohydrodynamic Model of a Hydraulic Rod Seal During Transient Operation

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Azam Thatte ◽  
Richard F. Salant
Keyword(s):  
Contact Mechanics ◽  
Contact Pressure ◽  
Fluid Pressure ◽  
Pressure Change ◽  
Elastic Behavior ◽  
Transient Operation ◽  
Fluid Films ◽  
Computational Framework ◽  
Pressure Distributions ◽  
Deformation Mechanics

A visco-elastohydrodynamic model of a hydraulic rod seal during transient operation has been developed. The model includes analyses of the macro- and microscale deformation mechanics and contact mechanics, and the microscale fluid mechanics. Viscoelasticity enters the analysis through the deformation mechanics and through the contact mechanics. A hybrid finite element-finite volume computational framework is developed to solve the highly coupled governing equations. Viscoelasticity is seen to affect the leakage and friction characteristics of the seal through its effects on the changing fluid pressure and contact pressure distributions as the rod velocity and sealed pressure change during a cycle. Compared with purely elastic behavior, viscoelasticity increases the fluid pressure and the contact pressure significantly in the sealing region closest to the sealed end, shifts the fluid pressure peaks away from the sealed end during the instroke, and enhances the cavitation during the outstroke. It results in thicker fluid films and produces a significant increase in the Poiseuille flow during the instroke.

Finite Element Analysis of the Compaction Processes for Hollow Three-Level (Class IV) Components

2005 ◽  
Vol 475-479 ◽  
pp. 4219-4222
Author(s):  
B.S. Ham ◽  
Beong Bok Hwang ◽  
D.H. Jang
Keyword(s):  
Yield Criterion ◽  
Average Density ◽  
Element Analysis ◽  
Powdered Metal ◽  
Pressure Distributions ◽  
Tension And Compression ◽  
Deformation Mechanics ◽  
Compaction Processes ◽  
Tooling System ◽  
Class Iv

The yield criterion describing asymmetric behavior of powdered metal compacts in tension and compression is introduced by modifying that used for sintered powdered metals. The plasticity theory related to the modified yield criterion is reviewed and summarized for a powdered metal compact. The constitutive equation is applied to the variational principle and its discritization is also introduced. Axisymmetric die pressings with copper powders were performed to see the deformation mechanics of hollow three-level parts. The simulation includes two different types of multiple-motion tooling compaction of a Class IV part of hollow three-level component. Predictions are made for density distributions, load-stroke relationships, average density as function of height, pressure distributions along the die-walls and punches, average compact densities at each level, and energy consumption for each pressing. The information from simulation can be used to synthesize the various punch motions in a multiple action tooling system.

Computer Modeling of a Tire under Cornering Loads

1989 ◽  
Vol 17 (2) ◽  
pp. 86-99 ◽  
Author(s):  
I. Gardner ◽  
M. Theves
Keyword(s):  
Finite Element Analysis ◽  
Geometric Approach ◽  
Lateral Force ◽  
Slip Angle ◽  
Element Analysis ◽  
Pressure Distributions ◽  
Slip Effects ◽  
Improved Accuracy ◽  
Nonlinear Geometric ◽  
Good Agreement

Abstract During a cornering maneuver by a vehicle, high forces are exerted on the tire's footprint and in the contact zone between the tire and the rim. To optimize the design of these components, a method is presented whereby the forces at the tire-rim interface and between the tire and roadway may be predicted using finite element analysis. The cornering tire is modeled quasi-statically using a nonlinear geometric approach, with a lateral force and a slip angle applied to the spindle of the wheel to simulate the cornering loads. These values were obtained experimentally from a force and moment machine. This procedure avoids the need for a costly dynamic analysis. Good agreement was obtained with experimental results for self-aligning torque, giving confidence in the results obtained in the tire footprint and at the rim. The model allows prediction of the geometry and of the pressure distributions in the footprint, since friction and slip effects in this area were considered. The model lends itself to further refinement for improved accuracy and additional applications.

Finite Element Analysis of the Distributed Vibration Absorbers for Structural Noise Control

2005 ◽  
Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Base Plate ◽  
Element Model ◽  
Fe Model ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Poroelastic Media ◽  
Hexahedral Elements ◽  
Component Models

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.

Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model

2012 ◽  
Vol 498 ◽  
pp. 42-54 ◽  
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Numerical Model ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Element Analysis ◽  
Progressive Failure Analysis

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.

Improved Method Based on Fluid Mechanics Analysis for Buoy Gauge Design and Experimental Research

2012 ◽  
Vol 163 ◽  
pp. 133-137
Author(s):  
Ao Yu Chen ◽  
Xu Dong Pan ◽  
Guang Lin Wang
Keyword(s):  
Fluid Mechanics ◽  
Experimental Research ◽  
Traditional Method ◽  
New Method ◽  
Improved Method ◽  
Advanced Method ◽  
Inner Surface ◽  
Mechanics Analysis ◽  
Linear Property

Traditional method of buoy gauge design is rather complicated, so an advanced method by building and solving fluid mechanics equations is proposed in this paper. The curve of the taper pipe inner surface is calculated, according to different buoy gravity and diameter. In order to examine the effect of this improved method, an experiment is carried out. Results show that linear property of the buoy gauge improved by new method is excellent.

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