Design of Irregular Slider Surface for Satisfying Specified Load Demands

2004 ◽  
Vol 127 (6) ◽  
pp. 1184-1190 ◽  
Author(s):  
Chin-Hsiang Cheng ◽  
Mei-Hsia Chang
Keyword(s):  
Pressure Distribution ◽  
Inverse Method ◽  
Design Method ◽  
Surface Shape ◽  
Problem Solver ◽  
Design Problems ◽  
Geometric Conditions ◽  
Slider Surface ◽  
Air Film

This study is to design the surfaces of sliders to meet the pressure distribution specified by the designers. The slider surfaces, in general, characterize an irregular profile. A direct problem solver, which is able to provide solutions for pressure distribution in the air film between the slider and the moving surface for various geometric conditions, is incorporated with an inverse method for determination of slider surface shape. In this report, a point-by-point design method is developed to improve the polynomial-function approach proposed in an earlier study (Cheng and Chang, 2004, J. of Tribology 126, pp. 519-526.) An exact solution for the two-dimensional design problems has also been developed to partly confirm the present approach. Results obtained from the present approaches are demonstrated by a comparison with the data from the existing method and the exact solutions to display the relative performance of the present method. The desired slider-shape design is a function of the bearing numbers. The slider shapes associated with different combinations of bearing numbers are investigated.

Shape Design for Surface of a Slider by Inverse Method

2004 ◽  
Vol 126 (3) ◽  
pp. 519-526 ◽  
Author(s):  
Chin-Hsiang Cheng ◽  
Mei-Hsia Chang
Keyword(s):  
Pressure Distribution ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Direct Problem ◽  
Inverse Method ◽  
Surface Shape ◽  
Shape Design ◽  
Problem Solver ◽  
Geometric Conditions ◽  
Resultant Forces

The aim of this study is to design the shapes of the surfaces of sliders to meet the load demands specified by the designers. A direct problem solver is built to provide solutions for pressure distribution between the slider and the rotor for various geometric conditions and load demands. The direct problem solver is then incorporated with the conjugate gradient method so as to develop an inverse method for the slider surface shape design. The specified load demands considered in this study are categorized into two kinds: (1) specified pressure distribution within the fluid film and (2) specified resultant forces plus specified centers of load. Several cases at various bearing numbers are tested to demonstrate the validity of the inverse shape design approach. Results show that the surface shape of a slider can be designed efficiently to comply with the specified load demands considered in the present study by using the inverse method.

An inverse method for determination of the interdiffusivity in aluminide coatings formed on superalloy

2004 ◽  
Vol 182 (1) ◽  
pp. 112-116 ◽  
Author(s):  
Hua Wei ◽  
Xiaofeng Sun ◽  
Qi Zheng ◽  
Guichen Hou ◽  
Hengrong Guan ◽  
...  
Keyword(s):  
Inverse Method ◽  
Aluminide Coatings

scholarly journals Investigation of a Stochastic Inverse Method to Estimate an External Force: Applications to a Wave-Structure Interaction

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
S. L. Han ◽  
Takeshi Kinoshita
Keyword(s):  
External Force ◽  
Inverse Method ◽  
Inverse Function ◽  
Wave Structure ◽  
Dynamic Responses ◽  
Structure Interaction ◽  
External Forces ◽  
Interaction Problem ◽  
Wave Structure Interaction

The determination of an external force is a very important task for the purpose of control, monitoring, and analysis of damages on structural system. This paper studies a stochastic inverse method that can be used for determining external forces acting on a nonlinear vibrating system. For the purpose of estimation, a stochastic inverse function is formulated to link an unknown external force to an observable quantity. The external force is then estimated from measurements of dynamic responses through the formulated stochastic inverse model. The applicability of the proposed method was verified with numerical examples and laboratory tests concerning the wave-structure interaction problem. The results showed that the proposed method is reliable to estimate the external force acting on a nonlinear system.

Inverse Design of Axial-Flow Compressor Blades Using Elastic Surface Algorithm in Subsonic and Transonic Flow Regimes With Separation

2016 ◽  
Author(s):  
M. H. Noorsalehi ◽  
M. Nili-Ahamadabadi ◽  
E. Shirani ◽  
M. Safari
Keyword(s):  
Pressure Distribution ◽  
Transonic Flow ◽  
Design Method ◽  
Axial Flow ◽  
Flow Regimes ◽  
Inverse Design ◽  
Elastic Surface ◽  
Axial Flow Compressor ◽  
Inverse Design Method ◽  
Flow Compressor

In this study, a new inverse design method called Elastic Surface Algorithm (ESA) is developed and enhanced for axial-flow compressor blade design in subsonic and transonic flow regimes with separation. ESA is a physically based iterative inverse design method that uses a 2D flow analysis code to estimate the pressure distribution on the solid structure, i.e. airfoil, and a 2D solid beam finite element code to calculate the deflections due to the difference between the calculated and target pressure distributions. In order to enhance the ESA, the wall shear stress distribution, besides pressure distribution, is applied to deflect the shape of the airfoil. The enhanced method is validated through the inverse design of the rotor blade of the first stage of an axial-flow compressor in transonic viscous flow regime. In addition, some design examples are presented to prove the effectiveness and robustness of the method. The results of this study show that the enhanced Elastic Surface Algorithm is an effective inverse design method in flow regimes with separation and normal shock.

Analytical approaches to the determination of pressure distribution under a plantar prominence

1997 ◽  
Vol 12 (3) ◽  
pp. S14-S15 ◽  
Author(s):  
J. Dingwell ◽  
T. Ovaert ◽  
D. Lemmon ◽  
P.R. Cavanagh
Keyword(s):  
Pressure Distribution ◽  
Analytical Approaches

Determination of Three-Dimensional Body Forms from Given Pressure Distribution Over Their Surfaces

1996 ◽  
Vol 40 (01) ◽  
pp. 22-27
Author(s):  
V. M. Pashin ◽  
V. A. Bushkovsky ◽  
E. L. Amromin
Keyword(s):  
Pressure Distribution ◽  
Three Dimensional ◽  
Bodies Of Revolution ◽  
Design Constraints ◽  
Pressure Distributions ◽  
Axisymmetric Bodies

A method for solving inverse three-dimensional problems in hydromechanics is proposed which makes it possible to fit desired pressure distributions within design constraints immediately in the course of calculations. Examples of the method of application are given for bodies of revolution in flows at nonzero drift angles. These flows are not axisymmetric. Bodies of revolution in them are very handy examples of demonstrations of the method, and these examples have many technical applications.

Design Method for Subsonic and Transonic Cascade With Prescribed Mach Number Distribution

1992 ◽  
Vol 114 (3) ◽  
pp. 553-560 ◽  
Author(s):  
O. Le´onard ◽  
R. A. Van den Braembussche
Keyword(s):  
Mach Number ◽  
Flow Field ◽  
Pressure Distribution ◽  
Velocity Component ◽  
Design Method ◽  
Normal Velocity ◽  
Flow Solver ◽  
Number Distribution ◽  
Mach Number Distribution ◽  
Transonic Cascade

A iterative procedure for blade design, using a time marching procedure to solve the unsteady Euler equations in the blade-to-blade plane, is presented. A flow solver, which performs the analysis of the flow field for a given geometry, is transformed into a design method. This is done by replacing the classical slip condition (no normal velocity component) by other boundary conditions, in such a way that the required pressure or Mach number distribution may be imposed directly on the blade. The unknowns are calculated on the blade wall using the so-called compatibility relations. Since the blade shape is not compatible with the required pressure distribution, a nonzero velocity component normal to the blade wall evolves from the new flow calculation. The blade geometry is then modified by resetting the wall parallel to the new flow field, using a transpiration technique, and the procedure is repeated until the calculated pressure distribution has converged to the required one. Examples for both subsonic and transonic flows are presented and show a rapid convergence to the geometry required for the desired Mach number distribution. An important advantage of the present method is the possibility to use the same code for the design and the analysis of a blade.

The Optimization for the Shape Profile of the Slider Surface Under Ultra-Thin Film Lubrication Conditions by the Rarefied-Flow Model

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Chin-Hsiang Cheng ◽  
Mei-Hsia Chang
Keyword(s):  
Thin Film ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Direct Problem ◽  
Problem Solver ◽  
Thin Film Lubrication ◽  
Rarefied Flow ◽  
Slider Surface ◽  
Inverse Knudsen Number ◽  
Film Lubrication

The optimization of the surface shape for a slider to meet the specified load demands under an ultra-thin film lubrication condition has been performed in this study. The optimization process is developed based on the conjugate gradient method in conjunction with a direct problem solver, which is built based on the rarefied-flow theory. The direct problem solver is able to predict the pressure distributions of the rarefied gas flows in the slip-flow, transition-flow, and molecular-flow regimes with a wide range of characteristic inverse Knudsen number. First, the validity of the direct problem solver has been verified by a comparison with the existing information for some particular cases, and then the developed direct problem solver is incorporated with the conjugate gradient method for optimizing the shape profile of the slider surface. The performance of the present optimization approach has also been evaluated. Results show that the shape profile of the slider surface can be efficiently optimized by using the present approach. Thus, a number of cases under various combinations of influential parameters, involving the characteristic inverse Knudsen number and the bearing numbers in the x- and y-directions, are investigated.

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