Behavior Of Slider Research Articles

Investigating Behavior of Slider–Crank Mechanisms with Bearing Failures Using Vibration Analysis Techniques

This study focuses on investigating the behavior of slider–crank mechanisms with different bearing failures using a vibration analysis technique. The reliability and lifespan of bearings are crucial for such mechanisms, which convert rotary motion to reciprocating motion. Previous research primarily addressed ball-bearing failures, neglecting needle bearings due to their specific applications. To bridge this gap, our experimental setup integrated both roller and ball bearings within a slider–crank mechanism. Vibration data were collected during normal operation, as well as under failure conditions of the ball and roller bearings. By analyzing the vibration signatures during simultaneous multiple failures, we gained insights into the nature of vibrations in the system. Furthermore, a mathematical model based on Hertzian contact was employed to calculate the theoretical frequency of ball bearings; however, due to the variable motion of the needle bearing, a novel mathematical model was proposed to estimate the defective impulse frequency, considering the inter-impact time between two impacts. The experimental results were compared with the healthy crank mechanism setup to draw meaningful conclusions. This research contributes to a comprehensive understanding of bearing failures in slider–crank mechanisms and provides valuable insights for designing reliable and long-lasting systems.

Advanced operational shock analysis considering ramp–disk contact for 2.5-inch stamped base HDD

We describe an operational shock analysis method that considers contact between the disk and the parking ramp in a 2.5-inch stamped base hard disk drive (HDD). Stamped base HDDs are susceptible to external shock, which can lead to contact between the disk and ramp. Contact between the disk and ramp affects the dynamic behavior of slider; hence it is important in an analysis of the response to operational shock. Here, we describe an operational shock simulation method using a nonlinear contact model for transient shock, together with a nonlinear air bearing spring. The vertical force and moments were calculated using the transient analysis, and applied as the inputs to a slider dynamic simulation. We used this method to investigate the characteristics of the head disk interface in response to applied shocks of various magnitudes and durations.

Simulation of Dynamic Behavior of Slider at Head/Disk Interface of Hard Disk Drives

The effect of contact between the sliders and disks on the flying characteristics of sliders in hard disk drives was modeled and analyzed. The differential equation of motion for slider was constructed based on slider/disk dynamics model with consideration of contact force. The contact was simplified as an elastic contact style and described by Hertzian contact method. The slider responses were simulated by using SimMechanics software. The results indicate that slider acts as periodic vibration under the contact force.

S1604-1-5 浮上制御型スライダのヒステリシス挙動に関する研究(ヘッド・ディスク・インターフェイス,社会変革を技術で廻す機械工学)

In this study, we conducted experiments to investigate the dynamic touchdown and takeoff hysteresis behavior of TFC sliders. The effect of lubricant film thickness on hysteresis dynamics of the TFC sliders was investigated in the experiments. We also performed similar experiments related to the hysteresis behavior of sliders without TFC and discussed the differences between the slider hysteresis dynamics for the various cases. A specific and interesting phenomenon was observed regarding the slider touchdown in the case of lubricant films with large thicknesses, suggesting the feasibility of developing surfing recording HDI based on thick lubricant films.

Long term friction: From stick‐slip to stable sliding

We have devised an original laboratory experiment where we investigate the frictional behaviour of a single crystal salt slider over a large number of deformation cycles. Because of its physical properties, salt, an analogue for natural faults, allows for frictional processes plastic deformation and pressure solution creep to operate on the same timescale. During the same experiment, we observe a continuous change of the frictional behaviour of the slider under constant conditions of stiffness, temperature and loading velocity. The stick‐slip regime is progressively vanishing, eventually reaching the stable sliding regime. Concomitantly, the contact interface, observed under the microscope, develops a striated morphology with contact asperities increase in length and width, arguing for an increase in the critical slip distance dc. Complementary experiments including velocity jumps show that the frictional parameters of the rate and state friction law, a and b, progressively vanish with accumulated slip. The ultimate stage of friction is therefore rate and state independent under our experimental conditions.

Longitudinally rough slider bearings with squeeze film formed by a magnetic fluid

The effect of longitudinal surface roughness on the behaviour of slider bearing with squeeze film formed by a magnetic fluid has been analysed. The roughness of the bearing surface is modelled by stochastic random variable with non‐zero mean, variance and skewness. The concerned Reynolds' equation is stochastically averaged with respect to the random roughness parameter. Results for bearing performance characteristics such as load carrying capacity of the bearing, centre of pressure, frictional force and coefficient of friction for different values of α (mean), σ (standard deviation) and ε (measure of symmetry) are numerically computed. In order to investigate the quantitative effect of roughness on the performance characteristics, four shapes namely; plane slider, exponential slider, hyperbolic slider and secant slider for the lubricant film are considered. The results are presented in tabular form as well as graphically. It is observed that the bearing performance is significantly affected by all the three parameters characterizing the surface roughness.

Investigation of Slider Vibrations Due to Contact With a Smooth Disk Surface

The dynamic behavior of pico sliders is investigated during slider-disk contacts as a function of velocity, pitch angle, crown height, and lubricant thickness using laser Doppler vibrometry and acoustic emission sensors. Analog and digital filtering methods are applied to distinguish air bearing and slider body resonances from frequencies related to disk runout, load beam design, and gimbal structure. Sliders with high pitch angle and small crown were found to exhibit smaller vibration amplitudes after slider-disk contacts than sliders with low pitch angle or large crown. The lubricant thickness of the disk was found to affect both the glide avalanche height of the disk and the dynamic behavior of the slider. The results show that roll and pitch frequencies of the air bearing increase with decreasing disk velocity.

Transient response of ultralow flying sliders over contaminated and textured surfaces

The transient flying dynamics of positive and negative pressure sliders over nonsmooth surfaces were investigated. Surface roughness was modeled by variously oriented sinusoidal waves, and contaminated surfaces were modeled as series of asperities and pits. A finite element algorithm was used which incorporates a generalized form of the Reynolds equation based upon the linearized Boltzmann equation. A new kinetic equation descriptive of ultralow flying was also discussed. Spectral analysis using fast Fourier transformation was adopted to explore the transient behavior of sliders in the frequency domain.

Modeling and Analysis of a Friction Drive Type Precise Actuator

In this work, a precies actuator which is capable of high positioning accuracy is developed. For estimation the dynamic behavior of the actuator, system modeling is performed by employing a stick-slip frection law. Dynamic characteristics over various types of driving input signals and vibraiton loci of the driving tip are examined by experiments. Phase differences between the input signals are applied, and the dynamic behavior of slider is investigated. From the simulation and experimental results, it is observed that the dynamic behaviors from the simulation results agree fairly well to those of the experimental results. Thisindicates that the model developed in this work is applicable to other precision mechanisms in which a friction farce is as improtant factor for actuation.