scholarly journals Response of a Warped Flexible Rotor with a Fluid Bearing

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Jim Meagher ◽  
Xi Wu ◽  
Chris Lencioni
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Equation Of Motion ◽  
Diagnostic Information ◽  
Flexible Rotor ◽  
Vibration Data ◽  
Rotor Model ◽  
Good Agreement

A two-complex-degrees-of-freedom model is developed and compared to experimental data for various amounts of rotor bow and its orientation to mass imbalance of the rotor. The equation of motion is developed by adding constant forces that rotate with the rotor to a Bently-Muszynska two-mode isotropic rotor model with a plane journal bearing. Diagnostic information discernable from probes at the bearing is explored and compared to midspan response, where previous research has concentrated. The model presented also extends earlier work by representing the effect of a nonrigid bearing. Good agreement between the analytical model and experiment demonstrates that the analysis presented can be useful to diagnose and balance residual shaft bow from probes located at the bearings, where vibration data are typically more available than midspan probes.

Modeling of Multibody Flexible Articulated Structures With Mutually Coupled Motions: Part II — Application and Results

1992 ◽  
Author(s):  
Jiechi Xu ◽  
Joseph R. Baumgarten
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Open Loop ◽  
Body Motion ◽  
Universal Joint ◽  
Open Loop System ◽  
Numerical Examples ◽  
Kinematic Properties ◽  
Good Agreement

Abstract The application of the systematic procedures in the derivation of the equations of motion proposed in Part I of this work is demonstrated and implemented in detail. The equations of motion for each subsystem are derived individually and are assembled under the concept of compatibility between the local kinematic properties of the elastic degrees of freedom of those connected elastic members. The specific structure under consideration is characterized as an open loop system with spherical unconstrained chains being capable of rotating about a Hooke’s or universal joint. The rigid body motion, due to two unknown rotations, and the elastic degrees of freedom are mutually coupled and influence each other. The traditional motion superposition approach is no longer applicable herein. Numerical examples for several cases are presented. These simulations are compared with the experimental data and good agreement is indicated.

Dynamic Characteristics of TEHD Tilt Pad Journal Bearing Simulation Including Multiple Mode Pad Flexibility Model

1993 ◽  
Author(s):  
Jinsang Kim ◽  
Alan Palazzolo
Keyword(s):  
Heat Transfer ◽  
Elastic Deformation ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Variable Viscosity ◽  
Global Analysis ◽  
Analysis Method ◽  
Stiffness And Damping ◽  
Modal Coordinates ◽  
Good Agreement

Abstract An approach for incorporating the heat transfer and elastic deformation effects into dynamic coefficient calculation is presented. A global analysis method is used, which finds the equilibrium pad tilt angles at each eccentricity position and includes cross-film variable viscosity, heat transfer effects in the lubricant, elastic deformation, heat conduction effects in the pads, and elastic deformation effect in the pivots. Deflection modes are used to approximate deformation of the top surface of the pads. The dynamic coefficients of a single pad are calculated at the equilibrium state of the bearing, based on numerical perturbation with respect to the bearing degrees of freedom. These include journal position, pad rotation, pivot deformation, and modal coordinates. The stiffness and damping coefficients are calculated and show very good agreement with experimental and numerical results from the existing literature.

A Simple Analytical Model to Simulate Oblique Ballistic Impact onto Fabric

2011 ◽  
Vol 110-116 ◽  
pp. 3453-3458
Author(s):  
Mohamad Ali Akbari ◽  
Golam Hosein Liaghat ◽  
Hadi Sabouri
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Ballistic Impact ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Good Agreement

A simple analytical model for oblique ballistic impact of projectiles into fabrics are presented. This model is extension of Chocron-Benloulo penetration model. Results are compared with experimental data. There is good agreement between analytical and experimental results.

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

Dynamics Analytical Model of Cutting Force in Metal Cutting Processing

2011 ◽  
Vol 308-310 ◽  
pp. 1211-1214
Author(s):  
Jian Ying Guo ◽  
Wen Bin Li ◽  
Shi Ying Wang ◽  
Ming Lv
Keyword(s):  
Experimental Data ◽  
Cutting Force ◽  
Analytical Model ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Static Balance ◽  
Impact Effect ◽  
New Formula ◽  
Suggested Formula ◽  
Good Agreement

Cutting force is an important parameter in machining. The static balance method and experience formulas had been adopted to find its value, but the theoretical calculated value is not good agreement with the experimental value for the same set of cutting conditions. In practical machining, the cutting tool has obvious impact effect on workpiece, so a dynamics analytical model for cutting process is established in this paper. Based on the proposed solution, a new formula for cutting force has been obtained. The suggested formula has shown to correspond well with the experimental data.

scholarly journals An analytical model for vortex at vertical intakes

2021 ◽  
Author(s):  
Hamed Sarkardeh ◽  
Morteza Marosi
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Vortex Formation ◽  
Surface Profile ◽  
Pressure Distributions ◽  
Free Surface Vortex ◽  
Spiral Form ◽  
Solution Velocity ◽  
Good Agreement ◽  
Surface Vortex

Abstract In the present paper, free surface vortex formation at intakes is investigated analytically. By assuming a spiral form for vortex streamlines, continuity and momentum equations were integrated and solved in a vortex flow domain. From this solution, velocity and pressure distributions were found above the intake under vortex action. An equation for the water surface profile was also found and compared with another research. By considering that in an air core vortex, pressure at the intake entrance drops to zero, a relationship was found for critical submerged depth and verified by experimental data and another analytical equation. It was concluded that the results of the proposed spiral analytical model had good agreement with the experimental data.

Nonlinear stress analysis of muskeg via finite element

1991 ◽  
Vol 28 (4) ◽  
pp. 613-629 ◽  
Author(s):  
R. N. Yong ◽  
A. M. O. Mohamed ◽  
R. G. Tali
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Key Words ◽  
Analytical Model ◽  
Constitutive Behavior ◽  
Experimental Program ◽  
Nonlinear Stress ◽  
Stress And Deformation ◽  
Element Technique ◽  
Good Agreement

The purpose of this paper is to provide a rational analytical means for predicting the performance of a muskeg deposit under loading. The analytical model employs the finite-element technique, which is extended to take into consideration the unusual constitutive behavior of the fibrous organic materials as well as the tension cut developing in these materials. The solution obtained using this model provides detailed stress and deformation fields within the loaded muskeg deposit. The applicability of the proposed analytical model is verified by conducting an appropriate experimental program. The results obtained from the model are found to be in good agreement with the experimental data. Key words: muskeg, loading, modelling, anisotropic, finite element, tension, compression.

scholarly journals Analytical model for electrohydrodynamic thrust

2020 ◽  
Vol 476 (2241) ◽  
pp. 20200220
Author(s):  
Ravi Sankar Vaddi ◽  
Yifei Guan ◽  
Alexander Mamishev ◽  
Igor Novosselov
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Momentum Transfer ◽  
Analytical Model ◽  
First Principles ◽  
Thrust Force ◽  
Propulsion Systems ◽  
One Dimensional ◽  
Charged Species ◽  
Good Agreement

Electrohydrodynamic (EHD) thrust is produced when ionized fluid is accelerated in an electric field due to the momentum transfer between the charged species and neutral molecules. We extend the previously reported analytical model that couples space charge, electric field and momentum transfer to derive thrust force in one-dimensional planar coordinates. The electric current density in the model can be expressed in the form of Mott–Gurney law. After the correction for the drag force, the EHD thrust model yields good agreement with the experimental data from several independent studies. The EHD thrust expression derived from the first principles can be used in the design of propulsion systems and can be readily implemented in the numerical simulations.

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

scholarly journals Analytical Model for Threshold Voltage in UTBB SOI MOSFET in Dynamic Threshold Voltage Operation

2017 ◽  
Vol 12 (2) ◽  
pp. 101-106
Author(s):  
V. T. Itocazu ◽  
K. R. A. Sasaki ◽  
V. Sonnenberg ◽  
J. A. Martino ◽  
E. Simoen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
Threshold Voltage ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Silicon On Insulator ◽  
Dynamic Threshold ◽  
Fully Depleted ◽  
Soi Mosfet ◽  
Good Agreement

This paper presents an analytical model to determine the threshold voltage in Ultrathin Body and Buried Oxide Fully Depleted Silicon on Insulator (UTBB FD SOI) MOSFETs operating in dynamic threshold (DT) voltage modes. The analytical model is based on implementing the quantum confinement effect and the DT restriction. The results show that the proposed analytical model in its simplicity provides a good agreement to the experimental data.

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