Magnetic Head-Media Interface Temperatures: Part 1—Analysis

1987 ◽  
Vol 109 (2) ◽  
pp. 243-251 ◽  
Author(s):  
B. Bhushan
Keyword(s):  
The Other ◽  
Temperature History ◽  
Asperity Contact ◽  
Thermal Interaction ◽  
Flash Temperature ◽  
Magnetic Head ◽  
Temperature Variations ◽  
Sliding Surfaces ◽  
Basic Model ◽  
Asperity Contacts

A “generalized” thermal analysis is described to estimate the flash temperature during sliding when both surfaces are of more or less equal roughness or one surface is substantially smoother than the other. High- and low-speed cases are considered. The basic model includes surface-topography statistics, frictional conditions, and mechanical and thermal parameters. Temperature history during the life of an individual asperity contact is calculated, from which average temperatures of an asperity contact are calculated. Thermal interaction of neighboring asperity contacts is considered. Then, an analysis is presented to show how individual asperity temperatures should be averaged. Temperature variations perpendicular to the sliding surfaces are also analyzed. Throughout the analysis, closed-form equations are developed, which can be conveniently used in the design of any sliding interface.

On the Static-Kinetic Friction Transition in Dry Contact of Rough Surfaces

2011 ◽  
Author(s):  
K. Farhang ◽  
D. Segalman ◽  
M. Starr
Keyword(s):  
Large Scale ◽  
Rough Surfaces ◽  
Tangential Force ◽  
Static Friction ◽  
Partial Slip ◽  
Small Scale ◽  
Asperity Contact ◽  
Kinetic Friction ◽  
Tangential Load ◽  
Asperity Contacts

This paper shows that the Mindlin problem involving two spheres in contact under the action of oscillating tangential force can lead to the account of static-kinetic friction transition. In Mindlin’s problem two spheres experience partial slip as a result of application of oscillating tangential load. When the problem is extended to multi-sphere contact, i.e. two rough surfaces, the application of tangential oscillating load results in partial slip for some asperity contacts while others experience full slip. Increase in the amplitude of the oscillating tangential force results in more contacts experiencing full slip, thereby decreasing the number of contacts in parial slip. Constitutive relation proposed by Mindlin at small scale, governing asperity interaction, is used to obtain the large scale slip function through a statistical summation of asperity scale events. The slip function establishes the fraction of asperity contact in full slip. The complement of the slip parameter is a fraction of asperities in partial slip. Through slip function it is shown that it is possible to define a slip condition for the entire surface. The derivation of the slip function allows the account of transition between static friction and kinetic friction.

Single Event Multiple Upset (SEMU) Tolerant Latch Designs in Presence of Process and Temperature Variations

2014 ◽  
Vol 24 (01) ◽  
pp. 1550007 ◽  
Author(s):  
Ramin Rajaei ◽  
Mahmoud Tabandeh ◽  
Mahdi Fazeli
Keyword(s):  
Propagation Delay ◽  
Soft Error ◽  
The Other ◽  
Design Parameters ◽  
Single Event ◽  
Temperature Variations ◽  
Single Event Upsets ◽  
Radiation Hardened ◽  
Simulation Results ◽  
Power Delay Product

In this paper, we propose two novel soft error tolerant latch circuits namely HRPU and HRUT. The proposed latches are both capable of fully tolerating single event upsets (SEUs). Also, they have the ability of enduring single event multiple upsets (SEMUs). Our simulation results show that, both of our HRPU and HRUT latches have higher robustness against SEMUs as compared with other recently proposed radiation hardened latches. We have also explored the effects of process and temperature variations on different design parameters such as delay and power consumption of our proposed latches and other leading SEU tolerant latches. Our simulation results also show that, compared with the reference (unprotected) latch, our HRPU latch has 57% and 34% improvements in propagation delay and power delay product (PDP) respectively. In addition, process and temperature variations have least effects on HRPU in comparison with the other latches. Allowing little more delay, we designed HRUT latch that can filter single event transients (SETs). HRUT has been designed to be immune against SEUs, SEMUs and SETs with an acceptable overhead and sensitivity to process and temperature variations.

Flash temperature and anti-wear tribofilm growth mechanisms by asperity contact in top-ring/liner conjunction of IC engines

2020 ◽  
Vol 146 ◽  
pp. 106186
Author(s):  
Wei Pu ◽  
Qin Zhang ◽  
Wang Zhang ◽  
Si Ren ◽  
Zhe Chen ◽  
...  
Keyword(s):  
Asperity Contact ◽  
Flash Temperature ◽  
Growth Mechanisms ◽  
Ic Engines

The Determination of Flash Temperature in Intermittent Magnetic Head/Disk Contacts Using Magnetoresistive Heads: Part I—Model and Laser Simulation

1993 ◽  
Vol 115 (1) ◽  
pp. 170-178 ◽  
Author(s):  
Yufeng Li ◽  
Aric R. Kumaran
Keyword(s):  
Theoretical Model ◽  
Temperature Response ◽  
Sensitivity Coefficient ◽  
Flash Temperature ◽  
Magnetic Head ◽  
Response Characteristics ◽  
Power Intensity ◽  
Magnetoresistive Sensor ◽  
Laser Simulation ◽  
Magnetoresistive Heads

The feasibility of using a magnetoresistive magnetic head to determine the flash temperature of intermittent magnetic head/disk contacts is investigated. A finite difference model is developed to study the effects of the magnetoresistive sensor height, the contact power intensity and the contact duration on the temperature response characteristics of the magnetoresistive sensor. A pulsed neody-minum:yttrium-aluminum-garnet laser is used as the heat source to simulate the contact and verify the model. The simulation results agree well with the theoretical model. Based on the theoretical model and laser simulation, a temperature sensitivity coefficient ζ is proposed to determine the surface temperature rise.

scholarly journals Competing Reverse Channels’ Performance with Sustainable Recycle Innovation Input

2020 ◽  
Vol 10 (16) ◽  
pp. 5429 ◽  
Author(s):  
Ran Liu ◽  
Bisheng Du ◽  
Wenwen Yuan ◽  
Guiping Li
Keyword(s):  
Hybrid Model ◽  
Closed Loop ◽  
Stackelberg Game ◽  
The Other ◽  
Third Party ◽  
Optimal Pricing ◽  
Pricing Strategies ◽  
Basic Model ◽  
Innovation Barriers ◽  
The Impact

Increasing attention to sustainable development issues and recycling are forcing the recyclers to use different incentives to capture more market share. Recycling innovation input is one of the effective topics in reverse competitive chains. Because of the importance of this issue, firstly, a basic closed-loop supply chain (CLSC) system is discussed that includes an integrated manufacturer and a third-party collector. Then the impact of the integration with the innovation input into third-party product collectors is considered. Eventually, two models are constructed. The first model is a basic model that includes an integrated manufacturer and one third-party collector with innovation investment. The other model is the hybrid model that includes an integrated manufacturer and two third-party collectors with and without innovation input. Stackelberg game models are used to study the optimal pricing strategies for all three models and players’ attitudes toward different scenarios. Finally, numerical analysis is presented. Our findings are generated on the following three aspects. The collector’s recycling choice, recycling innovation input, and influence on recyclers and manufacturers. It is found that the manufacturer will always choose to recycle and prefers the hybrid recycling market, which depends on the rate of collection and the compensation from production-collecting. Moreover, the results reveal that the highest return rate of recyclers occurred under the hybrid model. However, the recyclers may not be able to invest the sustainable recycle innovation input under the exorbitant innovation barriers.

Elasto-Plastic Asperity Contacts of Layered Media

2005 ◽  
Author(s):  
Qin Xie ◽  
Geng Liu ◽  
Tianxiang Liu ◽  
Ruiting Tong ◽  
Quanren Zeng
Keyword(s):  
Yield Criterion ◽  
Layered Media ◽  
Asperity Contact ◽  
Initial Stiffness ◽  
Programming Technique ◽  
Perfectly Plastic ◽  
Real Area Of Contact ◽  
Asperity Contacts ◽  
Elastic Perfectly Plastic ◽  
Von Mises

An elasto-plastic asperity contact model for layered media is developed in the work reported in this paper to analyze the influences of coating-substrate materials on contact when yielding and the strain-hardening properties of materials are taken into account. The finite element method, the initial stiffness method and the mathematical programming technique are employed to solve the model. The von Mises yield criterion is used to determine the inception of plastic deformation. The effects of different layer thickness and different coating-substrate materials on the contact pressure, real area of contact, average gap of rough surface, and stresses in layer and substrate under the elastic-perfectly-plastic and the elasto-plastic contact conditions are numerically investigated and discussed.

Bounding Solutions for a Plate Subjected to Variable Surface Temperature

1974 ◽  
Vol 41 (4) ◽  
pp. 941-946 ◽  
Author(s):  
A. R. S. Ponter ◽  
F. A. Leckie
Keyword(s):  
Surface Temperature ◽  
Pressure Vessels ◽  
Temperature History ◽  
Temperature Variations ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Variable Surface ◽  
Cyclic Temperature ◽  
Slow Cycling ◽  
Variable Surface Temperature

The paper considers the problem of a plate subjected to constant average in-plane stresses and temperature variations through the thickness of the plate. The material is described by a linear elastic/time-hardening viscous/perfectly plastic idealization. We show that the pertinent phenomenon which occurs due to a variable cyclic temperature history may be exhibited by computing bounding solutions which correspond to very fast and very slow cycling. This problem is typical of the situation which occurs in design of nuclear fuel cans and pressure vessels.

A Mixed-Lubrication Study of Journal Bearing Conformal Contacts

1997 ◽  
Vol 119 (3) ◽  
pp. 456-461 ◽  
Author(s):  
Qian (Jane) Wang ◽  
Fanghui Shi ◽  
Si C. Lee
Keyword(s):  
Film Thickness ◽  
Contact Pressure ◽  
Contact Area ◽  
Numerical Solutions ◽  
Mixed Lubrication ◽  
Lubricant Film ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Lubricant Film Thickness ◽  
Asperity Contacts

Numerical analyses of finite journal bearings operating with large eccentricity ratios were conducted to better understand the mixed lubrication phenomena in conformal contacts. The average Reynolds equation derived by Patir and Cheng was utilized in the lubrication analysis. The influence function, calculated numerically using the finite element method, was employed to compute the bearing deformation. The effects of bearing surface roughness were incorporated in the present analysis for the calculations of the asperity contact pressure and the asperity contact area. The numerical solutions of the hydrodynamic and asperity contact pressures, lubricant film thickness, and asperity contact area were evaluated based on a simulated bearing-journal geometry. The calculations revealed that the asperity contact pressure may vary significantly along both the width and the circumferential directions. It was also shown that the asperity contacts and the lubricant film thickness were strongly dependent on the bearing width, asperity orientation, and operating conditions.

Design and Evaluation of Electromagnetic Wobble Motor

2012 ◽  
Vol 24 (3) ◽  
pp. 480-486 ◽  
Author(s):  
Masaki Miyake ◽  
◽  
Koichi Suzumori ◽  
Kazuo Uzuka ◽  
Keyword(s):  
Control Method ◽  
Basic Structure ◽  
The Other ◽  
Motor Drive ◽  
Reduction Mechanism ◽  
Two Phase ◽  
Basic Model ◽  
Electric Equipment ◽  
And Control

The purpose of this work is to develop a thin, electromagnetic wobble motor with a large amount of torque, a motor thinner than conventional ones and able to be applied to portable electric equipment. We have developed a basic model of the motor 30 mm in diameter and 5 mm in thickness. In this paper, the basic structure and control method are first presented. Next, the design of the electromagnets and the three types of gear pairs, which have different pressure angles for the reduction mechanism, are presented. Finally, the motor drive experiments are performed using two types of drive: one is a two-phase drive, and the other is a four-phase drive. Three types of gear pairs are also shown. The motor works successfully, and its great potential to be mounted in thin, portable equipments is confirmed.

Thermal Elasto-Plastic Asperity Contacts of Layered Media

2006 ◽  
Vol 532-533 ◽  
pp. 721-724
Author(s):  
Rui Ting Tong ◽  
Geng Liu ◽  
Quan Ren Zeng ◽  
Tian Xiang Liu
Keyword(s):  
Stress Distribution ◽  
Contact Pressure ◽  
Coating Thickness ◽  
Frictional Coefficient ◽  
Hard Coating ◽  
Asperity Contact ◽  
Asperity Contacts ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Contact Stress Distribution

A thermal elasto-plastic asperity contact model is investigated in this paper, which takes into account the steady-state heat transfer and the asperity distortion due to thermal elasto-plastic deformations. A hard coating and a soft coating are applied to study the correlations between contact area and contact pressure, average gap and contact pressure, coating thickness and contours of the contact stress distribution et al. The effects of material properties, the coating thickness, frictional coefficient, and the heat input combinations on the stress distribution are investigated and discussed. The results may help to make an appropriate choice of the hard coating thickness.

Sign in / Sign up

Export Citation Format

Share Document