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.

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.

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.

ONE-STEP INVERSE APPROACH BASED ON QUASI-CONJUGATE-GRADIENT METHOD

2012 ◽  
Vol 11 (02) ◽  
pp. 165-172
Author(s):  
JINGXIN NA ◽  
WEI CHEN ◽  
HAIPENG LIU
Keyword(s):  
Conjugate Gradient Method ◽  
Conjugate Gradient ◽  
Gradient Method ◽  
Inverse Method ◽  
Inverse Approach ◽  
One Step ◽  
Unbalance Force ◽  
Newton Raphson ◽  
The One ◽  
Raphson Method

For the one-step inverse method, an iteration method based on a quasi-conjugate-gradient method is proposed to replace the Newton–Raphson method. It commences from the physical meaning of elemental unbalance force. It does not need to solve the system of finite element equations. It not only inherits the advantage of conjugate gradient method but also avoids non-convergence of the solving process. Finally, the validity of the algorithm proposed is proved by comparing the simulation results obtained by the method in this paper with those obtained through the module of one-step inverse method in Dynaform and practical drawn parts.

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