scholarly journals A Description of Multiscale Modeling for the Head-Disk Interface Focusing on Bottom-Level Lubricant and Carbon Overcoat Models

2013 ◽  
Vol 2013 ◽  
pp. 1-27 ◽  
Author(s):  
Myung S. Jhon ◽  
Pil Seung Chung ◽  
Robert L. Smith ◽  
Lorenz T. Biegler
Keyword(s):  
Multiscale Modeling ◽  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Molecular Architecture ◽  
Head Disk Interface ◽  
Carbon Overcoat ◽  
Modeling Tools ◽  
Molecular Conformations ◽  
Disk Interface ◽  
Modeling Methodology

The challenges in designing future head disk interface (HDI) demand efficient theoretical modeling tools with flexibility in investigating various combinations of perfluoropolyether (PFPE) and carbon overcoat (COC) materials. For broad range of time and length scales, we developed multiscale/multiphysical modeling approach, which can bring paradigm-shifting improvements in advanced HDI design. In this paper, we introduce our multiscale modeling methodology with an effective strategic framework for the HDI system. Our multiscale methodology in this paper adopts a bottom to top approach beginning with the high-resolution modeling, which describes the intramolecular/intermolecular PFPE-COC degrees of freedom governing the functional oligomeric molecular conformations on the carbon surfaces. By introducing methodology for integrating atomistic/molecular/mesoscale levels via coarse-graining procedures, we investigated static and dynamic properties of PFPE-COC combinations with various molecular architectures. By bridging the atomistic and molecular scales, we are able to systematically incorporate first-principle physics into molecular models, thereby demonstrating a pathway for designing materials based on molecular architecture. We also discussed future materials (e.g., graphene for COC, star-like PFPEs) and systems (e.g., heat-assisted magnetic recording (HAMR)) with higher scale modeling methodology, which enables the incorporation of molecular/mesoscale information into the continuum scale models.

Modeling of Amorphous Carbon Overcoat for Investigation of Lubricant Transfer at the Head-Disk Interface

2014 ◽  
Author(s):  
Young Woo Seo ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drives ◽  
Intermolecular Forces ◽  
Realistic Model ◽  
Coarse Grained ◽  
Attractive Potential ◽  
Head Disk Interface ◽  
Carbon Overcoat ◽  
Lubricant Transfer ◽  
Disk Interface ◽  
Dynamics Simulations

In current hard disk drives, the spacing between the slider and the disk is reduced to the order of 1–2 nm. At such a narrow spacing, intermolecular forces at the head-disk interface play an important role in achieving a stable slider-disk interface. Even in the absence of actual head-disk contact, lubricant transfer between a slider and a disk may occur. Transferred lubricant can change the flying characteristics of the slider in subsequent read-write operations. It is therefore apparent that lubricant transfer at the head-disk interface is undesirable. In this paper, molecular dynamics simulations were performed to investigate lubricant transfer between a slider and a disk. A so-called coarse-grained bead spring (CGBS) model was implemented. In this model, the Lennard-Jones potential, the short-range polar attractive potential, and the finitely extensible nonlinear elastic potential functions were used to describe the intermolecular interactions at the head-disk interface. Also, in order to develop a realistic model of the carbon overcoat, different modeling approaches are discussed, including the use of rigid coarse-grained beads and a 3-body Tersoff potential function.

scholarly journals Multiscale modeling of organic molecules contamination in head-disk interface under high thermal stress

AIP Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 056514
Author(s):  
Wonyup Song ◽  
Pil Seung Chung ◽  
Lorenz T. Bielger ◽  
Myung S. Jhon
Keyword(s):  
Thermal Stress ◽  
Multiscale Modeling ◽  
Organic Molecules ◽  
Head Disk Interface ◽  
Disk Interface

Multiscale Modeling of Head Disk Interface

2010 ◽  
Vol 46 (6) ◽  
pp. 2401-2404 ◽  
Author(s):  
Dehee Kim ◽  
Pil Seung Chung ◽  
Parag Jain ◽  
Sesha Hari Vemuri ◽  
Myung S. Jhon
Keyword(s):  
Multiscale Modeling ◽  
Head Disk Interface ◽  
Disk Interface

Dynamic Friction Study on Voltage Assisted Overcoat Wearing Head-Disk Interface

2016 ◽  
Author(s):  
Sukumar Rajauria ◽  
Sripathi Canchi ◽  
Erhard Schreck ◽  
Bruno Marchon ◽  
Qing Dai
Keyword(s):  
Quantitative Analysis ◽  
Strain Gauge ◽  
Dynamic Friction ◽  
Head Disk Interface ◽  
Friction Measurement ◽  
Carbon Overcoat ◽  
Sliding Speed ◽  
Disk Interface ◽  
Positive Voltage ◽  
Friction Study

Voltage assisted wear at the head and the disk interface is investigated with the motive of understanding the head overcoat wear processes. In this work, we report the quantitative analysis of voltage assisted wear on head carbon overcoat at high sliding speed interfaces. We found that voltage assisted TFC head wear acts asymmetrically at the interface with positive voltage leading to high wear. We quantitatively analyzed the interface using a strain gauge based friction measurement.

Hierarchical Multiscale Modeling Method for Head/Disk Interface

2011 ◽  
Vol 47 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Myung S. Jhon ◽  
Robert Smith ◽  
Sesha Hari Vemuri ◽  
Pil Seung Chung ◽  
Dehee Kim ◽  
...  
Keyword(s):  
Multiscale Modeling ◽  
Modeling Method ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Hierarchical Multiscale

Effect of Laser Heating on Nanoscale Wear of DLC Thin Films in an Air Environment

2017 ◽  
Author(s):  
Norio Tagawa ◽  
Hiroshi Tani ◽  
Shinji Koganezawa ◽  
Renguo Lu
Keyword(s):  
Thin Films ◽  
Magnetic Recording ◽  
Laser Heating ◽  
Head Disk Interface ◽  
Carbon Overcoat ◽  
Disk Interface ◽  
Head Slider ◽  
Boundary Lubricant ◽  
Lubricant Films ◽  
Nanoscale Wear

To achieve magnetic recording densities greater than 10 Tb/in2, the head-disk interface (HDI) spacing is required to be less than 2–3 nm. Thus far, various technologies, such as heat assisted magnetic recording (HAMR), have been studied and developed to achieve such high magnetic recording densities [1]. To ensure the practical applicability of HAMR, it is important to understand the reliability of perfluoropolyether (PFPE) boundary lubricant films and carbon overcoat or diamond-like carbon (DLC) thin films used on the head slider and disk surfaces under heating conditions [2].

Novel multiscale modeling and its application to integrated head disk interface simulation

2005 ◽  
Vol 97 (10) ◽  
pp. 10P310 ◽  
Author(s):  
Qian Guo ◽  
Haigang Chen ◽  
Woo Tae Kim ◽  
Myung S. Jhon
Keyword(s):  
Multiscale Modeling ◽  
Head Disk Interface ◽  
Disk Interface

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

scholarly journals Designing of Drive Systems in the Aspect of the Desired Spectrum of Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2562
Author(s):  
Tomasz Dzitkowski ◽  
Andrzej Dymarek ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
Lukasz Orzech ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Dynamic Parameters ◽  
Synthesis Algorithm ◽  
Moments Of Inertia ◽  
Driving System ◽  
Six Degrees Of Freedom ◽  
Resonance Frequencies ◽  
Drive Systems ◽  
Power Component

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

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