An Optimum Design of the Transverse Pressure Contour Slider for Enhanced Flying Characteristics

1997 ◽  
Vol 119 (3) ◽  
pp. 520-524 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Optimum Design ◽  
Design Method ◽  
Optimization Technique ◽  
Flying Height ◽  
Step Width ◽  
Skew Angle ◽  
Sqp Method ◽  
Design Synthesis ◽  
Transverse Pressure ◽  
Design Variables

This paper proposes a design method for determining the configuration of a TPC slider by using an optimization technique in order to meet the desired flying characteristics over the entire recording band. The desired flying characteristics considered in this study are to minimize the variation in flying height from a target value, to maintain the pitch angle as large as possible, to keep the roll angle as small as possible, and to keep the outside rail to fly lower than the inside rail. The design variables selected are left-side step width, pad width, right-side step width, side step depth, front taper height, and pivot offset in the transverse direction of the slider. The sequential quadratic programming (SQP) method in Automated Design Synthesis (ADS) is used to efficiently find the optimum design variables which simultaneously meet all the desired flying characteristics. To validate the suggested design method, a computer program is developed and applied to the configuration design of two TPC slider models positioned by a rotary actuator. The optimum configurations of each slider model are automatically obtained for three different target flying heights with the same predefined skew angle range without any difficulty. This shows the effectiveness of the proposed design method in comparison with the conventional one based on the parametric study.

Design Optimization of the Taper-Flat Slider Positioned by a Rotary Actuator

1995 ◽  
Vol 117 (4) ◽  
pp. 588-593 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Optimization Technique ◽  
Leading Edge ◽  
Flying Height ◽  
Air Bearing ◽  
Skew Angle ◽  
Optimum Configuration ◽  
Rotary Actuator ◽  
Design Variables ◽  
Augmented Lagrange Multiplier ◽  
Typical Configuration

In this paper, an optimization technique is utilized to find an optimum configuration of the taper-flat slider positioned by a rotary actuator for enhanced static air-bearing characteristics. The aim of optimization consists in simultaneously minimizing the variation in flying height from a target value, maximizing the smallest pitch angle, and minimizing the largest roll angle, over the entire magnetic recording band. As the design variables, the leading edge taper angle and rail width of a taper-flat slider, and the skew angle at the inside track are chosen since they seem to be the most influential parameters on air-bearing characteristics. The optimum design variables are automatically obtained by using the augmented Lagrange multiplier method, and the static characteristics of the optimally designed sliders are found to be superior to those of the taper-flat sliders of typical configuration over the entire recording band. Results obtained for three taper-flat slider models are reported, showing the effectiveness of the proposed design scheme.

Improvement of the Static and Dynamic Characteristics of Magnetic Head Sliders by Optimum Design

1999 ◽  
Vol 122 (1) ◽  
pp. 280-287 ◽  
Author(s):  
Hiromu Hashimoto ◽  
Yasuhisa Hattori
Keyword(s):  
Objective Function ◽  
Optimum Design ◽  
Amplitude Ratio ◽  
Optimization Technique ◽  
Hard Disk Drives ◽  
Maximum Amplitude ◽  
Disk Surface ◽  
Operating Conditions ◽  
Magnetic Head ◽  
Design Variables

The aim of this paper is to develop a general methodology for the optimum design of magnetic head sliders in improving the spacing characteristics between a slider and disk surface under static and dynamic operating conditions of hard disk drives and to present an application of the methodology to the IBM 3380-type slider design. To generate the optimal design variables, the objective function is defined as the weighted sum of the minimum spacing, the maximum difference in the spacing due to variation of the radial location of the head, and the maximum amplitude ratio of the slider motion. Slider rail width, taper length, taper angle, suspension position, and preload are selected as the design variables. Before the optimization of the head, the effects of these five design variables on the objective function are examined by a parametric study, and then the optimum design variables are determined by applying the hybrid optimization technique, combining the direct search method and successive quadratic programming. From the obtained results, the effectiveness of optimum design on the spacing characteristics of magnetic heads is clarified. [S0742-4787(00)03701-2]

Reliability-based optimum design for mechanical problems using genetic algorithms

2008 ◽  
Vol 222 (9) ◽  
pp. 1791-1799 ◽  
Author(s):  
Y-T Tsai ◽  
H-C Chang
Keyword(s):  
Genetic Algorithms ◽  
Optimum Design ◽  
Optimization Technique ◽  
Structural Complexity ◽  
Optimal Solution ◽  
Unconstrained Minimization ◽  
Reliability Design ◽  
Performance Indexes ◽  
Design Variables ◽  
Relationship Of

A reliability oriented design approach for mechanical or structural components is implemented primarily based on strength—stress interference (SSI) theory. This paper demonstrates a principle for combining SSI theory and an optimization technique for developing a reliability-based optimum design for mechanical problems. The independently paired information (strength and stress distributions) are basic while progressing reliability design. For a complex system, the independently paired information sometimes is not easily clarified due to the structural complexity or the coupled relationship of the loads. To treat these problems, the paper proposes to express the independently paired information from the viewpoint of supply-requirement of a design in performance. The supply (provided by a design) is analogized to the strength as well as the requirement (requested by the customer) to the stress. Based on the viewpoint of supply-requirement, the paper presents four types of performance-related reliability measurement to fulfil reliability design for mechanical problems. The reliability measurements are derived according to the related design variables that formulate the performance indexes. Next, the designed problem expressed with probabilistic formulation is transformed into an unconstrained minimization problem subjected to the constraints of the performance needs and its reliability target. Genetic algorithms (GAs) are used to find the optimal solution for the reliability design problem. The related theories and an example of design are reported in this paper to depict the proposed method.

An Optimization Method for Design of Subambient Pressure Shaped Rail Sliders

1999 ◽  
Vol 121 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Dong-Hoon Choi ◽  
Tae-Sik Kang
Keyword(s):  
Design Methodology ◽  
Optimization Method ◽  
Flying Height ◽  
Air Bearing ◽  
Bearing Surface ◽  
Programming Technique ◽  
Design Synthesis ◽  
Method Of Feasible Directions ◽  
Design Variables ◽  
Simulation Results

This study proposes a design methodology for determining configurations of subamient pressure shaped rail sliders by using a nonlinear programming technique in order to meet the desired flying characteristics over the entire recording band. The desired flying characteristics considered in this study are to minimize the variation in flying height from a target value, to keep the pitch angle within a suitable range, and to ensure that the outside rail flies lower than the inside rail even with the roll distribution due to manufacturing process. The design variables selected are recess depth, geometry of the air bearing surface, and pivot location in the transverse direction of the slider. The method of feasible directions in Automated Design Synthesis (ADS) is utilized to automatically find the optimum design variables which simultaneously meet all the desired flying characteristics. To validate the suggested design methodology, a computer program is developed and applied to a 30 percent/15 nm twin rail slider and a 30 percent/15 nm tri-rail slider. Simulation results for both sliders demonstrated the effectiveness of the proposed design methodology by showing that the flying characteristics of the optimally designed sliders are enhanced in comparison with those of the initial ones.

scholarly journals The Isotropic Material Design of In-Plane Loaded Elasto-Plastic Plates

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7430
Author(s):  
Sławomir Czarnecki ◽  
Tomasz Lewiński
Keyword(s):  
Optimum Design ◽  
Isotropic Material ◽  
Plastic Material ◽  
Design Method ◽  
Unit Cost ◽  
Yield Condition ◽  
Material Design ◽  
Approximate Solutions ◽  
Constrained Problems ◽  
Design Variables

This paper puts forward a new version of the Isotropic Material Design method for the optimum design of structures made of an elasto-plastic material within the Hencky-Nadai-Ilyushin theory. This method provides the optimal layouts of the moduli of isotropy to make the overall compliance minimal. Thus, the bulk and shear moduli are the only design variables, both assumed as non-negative fields. The trace of the Hooke tensor represents the unit cost of the design. The yield condition is assumed to be independent of the design variables, to make the design process as simple as possible. By eliminating the design variables, the optimum design problem is reduced to the pair of the two mutually dual Linear Constrained Problems (LCP). The solution to the LCP stress-based problem directly determines the layout of the optimal moduli. A numerical method has been developed to construct approximate solutions, which paves the way for constructing the final layouts of the elastic moduli. Selected illustrative solutions are reported, corresponding to various data concerning the yield limit and the cost of the design. The yield condition introduced in this paper results in bounding the values of the optimal moduli in the places of possible stress concentration, such as reentrant corners.

Optimal Design of HDD Air-Lubricated Slider Bearings for Improving Dynamic Characteristics and Operating Performance

2000 ◽  
Vol 123 (3) ◽  
pp. 541-547 ◽  
Author(s):  
Tae-Sik Kang ◽  
Dong-Hoon Choi ◽  
Tae-Gun Jeong
Keyword(s):  
Steady State ◽  
Dynamic Characteristics ◽  
Optimization Technique ◽  
Operating Performance ◽  
Flying Height ◽  
Air Bearing ◽  
Skew Angle ◽  
Weighting Method ◽  
Lubrication Equation ◽  
Target Values

Flying attitudes of the slider, which are flying height, pitch, and roll, are affected by air-flow velocity, skew angle, and manufacturing tolerances. In the traditional design process of air-bearing surfaces, we have considered only the steady state flying attitude over the recording band. To reduce the flying height variation during track seek as well as in steady state, we design a new shape for air-bearing surfaces. An optimization technique is used to improve the dynamic characteristics and operating performance of the new air-bearing surface shapes. The quasistatic approach is used in the numerical simulation of the track seek operation because the skew angle effect dominates the inertial effect even at high seek velocities. The perturbation method is applied to the lubrication equation to obtain the air-bearing stiffness. We employ the method of modified feasible directions and use the weighting method to solve the multicriteria optimization problem. The optimally designed sliders show enhanced flying and dynamic characteristics. The steady state flying heights are closer to the target values and the flying height variations during track seek operation are smaller than those for the original ones. The pitch and roll angles are kept within suitable ranges over the recording band during track seek operation as well as in steady state. The air-bearing stiffnesses of the optimally designed sliders are larger than those of the original ones.

Optimum design of composite structures subjected to multiple displacement constraints

1993 ◽  
Vol 28 (2) ◽  
pp. 135-141 ◽  
Author(s):  
W J Li ◽  
J Y Chen
Keyword(s):  
Optimum Design ◽  
Composite Structures ◽  
Optimization Technique ◽  
Energy Criterion ◽  
System Level ◽  
Multilevel Optimization ◽  
Component Level ◽  
Design Variables ◽  
Displacement Constraints ◽  
Criterion Method

The paper presents an effective method for achieving the optimum design of composite structures subjected to multiple displacement constraints. Based on the optimality criterion method and some approximate engineering assumptions, this paper introduces a simplified expression relating the design variables to Lagrange multipliers, which correspond to displacement constraints. Therefore, the optimal design variables are derived from a smaller number of unknown coefficients. Thus the computational efficiency is greatly enhanced. Furthermore, the multilevel optimization technique is adopted. The optimum design variables are obtained in system level optimization. For more detailed design the ply thicknesses of a composite plate are adjusted in component level optimization by using the maximum strain energy criterion. A cantilever composite beam, subjected to strength and multiple displacement constraints, is studied as the illustrative example. The computational results indicate the efficiency of the method.

Automated Design Synthesis of Articulated Heavy Vehicles With Active Trailer Steering Systems

2010 ◽  
Author(s):  
Md Manjurul Islam ◽  
Yuping He ◽  
Timothy D. Webster
Keyword(s):  
Design Method ◽  
Automated Design ◽  
Driver Model ◽  
Lateral Stability ◽  
Heavy Vehicles ◽  
Design Synthesis ◽  
Vehicle Performance ◽  
High Speeds ◽  
Design Variables ◽  
Low Speeds

This paper presents an automated design synthesis approach for articulated heavy vehicles (AHVs) with active trailer steering (ATS) systems. AHVs have poor maneuverability when traveling at low speeds. Moreover, AHVs exhibit unstable motion modes at high speeds. To address the problem of maneuverability, ‘passive’ trailer steering systems have been developed. These systems improve low-speed performance, but feature with low lateral stability at high speeds. Some ATS systems have been proposed to improve highspeed lateral stability. However, these systems typically degrade maneuverability when applied at low speeds. To tackle this conflicting design problem, a systematic method is proposed for the design of AHVs with ATS systems. This new design method has the following features: the optimal active design variables of the ATS systems and the optimal passive design variables of the vehicle are identified in a single design loop; in the design process, to evaluate the vehicle performance measures, a driver model is introduced and it ‘drives’ the vehicle model based on the well-defined testing specifications. Through the design optimization of an ATS system for an AHV with a tractor and a full trailer, this single design loop (SDL) method is compared against a published two design loop (TDL) method. The benchmark investigation shows that the former can determine better trade-off design solutions than those derived by the latter. This SDL method provides an effective approach to automatically implement the design synthesis of AHVs with ATS systems.

Optimum Design Based on Damage Tolerance for Overall Beam Structure

2014 ◽  
Vol 575 ◽  
pp. 363-369
Author(s):  
Fei Chang ◽  
Shu Lin Li ◽  
Jun Jie Yin ◽  
Xiao Peng Shi ◽  
Bin Zhou
Keyword(s):  
Optimum Design ◽  
Residual Strength ◽  
Damage Tolerance ◽  
Design Method ◽  
Aircraft Design ◽  
Support Vector ◽  
Beam Structure ◽  
Agent Model ◽  
Design Variables ◽  
Minimum Residual

Focus on the problem that traditional aircraft design thought can’t meet the security and economy requirement of modern aircraft, studying the optimum design method based on damage tolerance for overall beam. For example with aircraft overall beam, constructed the optimization model based on support vector machine agent model with the lightest weight of the structure as the optimization objective, the minimum residual strength value as the constraint, section parameters as the design variables, through mathematical programming, get the optimization results under different residual strength requirement value, and calculate the crack growth life.

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