Advanced air-bearing modeling for operational shock analysis of a 2.5-inch HDD with ramp–disk contact

2015 ◽  
Vol 21 (12) ◽  
pp. 2547-2556 ◽  
Author(s):  
Kyoung-Su Park ◽  
No-Cheol Park
Author(s):  
Kyoung-Su Park ◽  
Geonyup Lim ◽  
No-Cheol Park ◽  
Young-Pil Park

As use of mobile computing devices has spread rapidly, it is very important to accurately analyze and predict anti-shock performance of the HDD system. In this paper, we proposed an efficient air bearing modeling method to analyze op-shock performance for the in 2.5-inch HDD system with ramp-disk contact behavior. We first constructed the decoupled approach method using linear air bearing springs in finite element method and used the Lagrange multiplier method for contact modeling between disk and ramp. With the constructed finite element model, the effect of linear air bearing stiffness was investigated in the decoupled method. We found that air bearing stiffness affects the behavior of the slider dominantly in the HDDs system with ramp-disk contact. Based on the numerical results, the advanced method able to efficiently reflect air bearing characteristics was proposed and evaluated.


2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Puneet Bhargava ◽  
David B. Bogy

This paper discusses the effect of varying the suspension load dimple location on the shock robustness of small form factor hard disk drives. We use the CML shock simulator, which simulates the structural as well as the air bearing dynamics of the disk drive simultaneously. The location of the dimple is varied and simulations are run for various load positions on the back of the slider, while adjusting the pitch static attitude (PSA) and the roll static attitude (RSA) of the slider such that the flying attitude of the slider remains the same. We simulate shocks of 0.5 ms pulse width for a commercially available slider and suspension designs for a 1 in. drive. We observe that shock resistance is optimal when the dimple is offset toward the leading edge of the slider. This behavior is explained on the basis of a linearized air bearing model. It is also observed that moving the dimple too much toward the leading edge causes the mechanism of shock failure to change resulting in lower shock tolerances.


2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wei Hua ◽  
Kang Kee Ng ◽  
Shengkai Yu ◽  
Weidong Zhou ◽  
Kyaw Sett Myo

For a thermal flying-height control (TFC) slider, its heater is usually provided with DC voltage. However, recently, both DC and AC voltages may be supplied to the heater. Unlike supplying AC voltage to the slider and disk in the past, the AC voltage to the heater will not only produce a thermal protrusion on the slider, but also leaves a part of the AC voltage on the slider/disk interface. The voltage acts as the electrostatic force and can be used for further control of the slider, even in the drive level. Simulations show that the flying height modulation is highly related to the AC frequency. By sweeping the AC frequencies while monitoring the flying height and pitch angle modulations, the first and second pitch modes of air bearing frequencies can be experimentally obtained without slider/disk contact. The roll mode frequency is also obtainable when the skew angle is not zero. The simulation results agree well with the experimental results obtained by a laser Doppler vibrometer (LDV). Therefore, the sweeping AC frequency method provides a practical scheme to obtain the air bearing frequencies without any slider/disk contact, even in the drive level.


Author(s):  
Geonyup Lim ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park ◽  
Yonghyun Lee ◽  
...  

This research investigates to analyze the effect of design parameters on operational shock (op-shock) performance. First, op-shock simulation was constructed with a nonlinear contact model and a nonlinear air bearing spring. Then, this simulation was used to investigate the anti-shock performance by design parameters.


2006 ◽  
Vol 129 (1) ◽  
pp. 153-160 ◽  
Author(s):  
P. Bhargava ◽  
D. B. Bogy

As nontraditional applications of hard disk drives emerge, their mechanical robustness during the operating state is of greater concern. Over the past few years, there has been an increasing application of small form factor (1in. and smaller) hard disk drives in portable consumer appliances and gadgets. A procedure for simulating the operational shock response of a disk-suspension-slider air bearing system is proposed in this paper. A coupled structural-fluid model is presented which can be used to obtain the dynamic response of the slider-suspension-disk system. A commercial program, ANSYS, is used for the finite element models of the suspension and the disk, while the CML dynamic air bearing code is used to concurrently solve the air bearing equations of the system. We obtain not only the responses of the structural components, but also the responses of the air bearing slider. The procedure is convenient for practical application as well as being highly accurate, since it implicitly solves the structural and air bearing problems simultaneously. It is used to simulate the shock response of a 1in. drive. The air bearing has different responses for upward and downward shocks (which are referred to as positive and negative shocks, respectively). For negative shocks, slider-disk contacts are observed to occur when a strong shock is applied, however, the air bearing does not collapse. For positive shocks, we observe a collapse of the air bearing when the shock is sufficiently strong, which is followed by severe contacts between the slider and the disk due to the “head-slap” phenomenon.


1993 ◽  
Vol 115 (3) ◽  
pp. 370-375 ◽  
Author(s):  
T. G. Jeong ◽  
D. B. Bogy

The dynamic loading process in hard disk drives is simulated numerically. The effects of the slider’s loading velocity and initial pitch and roll on its dynamics during loading, as well as on slider-disk contacts, are studied by using the dynamic loading simulator. The air bearing forces due to the squeezing and shearing flows are calculated and their contributions to the dynamics of the slider during loading are investigated. Slider-disk contacts are considered in the numerical simulation through generalized impulse-momentum equations. Slider-disk contact criteria are obtained from the numerical simulation, and they are compared with those obtained from a previous experimental parameter study.


Author(s):  
Geonyup Lim ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park

This research proposes an operational shock analysis method that considers contact between a disk and the parking ramp for 2.5 inch stamped base HDD. The 2.5 inch stamped base HDD is susceptible to the external shock. The external shock increased the possibility of contact between disk and ramp. The contact between disk and ramp affect to the dynamic behavior of slider. Here, we describe a simulation method for a nonlinear contact model and a nonlinear air bearing spring. The vertical force and moment were calculated using a transient analysis, and applied as an input to a dynamic slider simulation. Simulations were used to investigate the characteristics of the head disk interface in response to shocks of various magnitudes and duration.


Sign in / Sign up

Export Citation Format

Share Document