Mitigation of flow induced vibration of head gimbal assembly

Zhang, Qi De; Tan, Chok Shiong; Sundaravadivelu, K.; Suriadi, M.A.; Chin, G.L.; Yip, T.H.; Ong, Eng Shi; Liu, Ning Yu

doi:10.1007/s00542-009-0817-2

Cited by 25 publications

(16 citation statements)

References 11 publications

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“…They showed that reduction of the vibrations is related to the change of the airflow between disks. The effect of airflow on vibration of disk and arm has been reported [6]- [9]. The airflow in recent HDDs become more complicated because of aerodynamic parts, such as a spoiler and a bypass channel, introduced in HDDs for reducing FIV.…”

Section: Introductionmentioning

confidence: 98%

Airflow-Simulation by Voxel Mesh Method for Complete Hard Disk Drive Structure

2009

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Numerical fluid simulation based on the voxel-mesh method was applied to the whole structure of 3.5-inch hard-disk drives. The voxel mesh of a hard-disk drive (HDD) including all components can be generated automatically from a computer-aided design (CAD) software in a short time. The simulation results were compared with the experimental measurements by particle image velocimetry (PIV). The airflow simulation with a whole-HDD-structure model exhibits a better agreement with the PIV results than that of a partial model (namely, a calculation region sliced between two disks) does, and it indicates the existence of an entire flow (from between the disks, up between the shroud gap and filter area, and onto the top disk) in the vertical direction throughout the HDD. This method is useful for airflow simulation of a model with complicated geometry such as that of hard disk drives.Index Terms-CFD, hard-disk drives (HDD), particle image velocimetry (PIV), voxel.

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Section: Introductionmentioning

confidence: 98%

Airflow-Simulation by Voxel Mesh Method for Complete Hard Disk Drive Structure

2009

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“…Additionally, a weight-saving hole in the middle of the actuator arm induced a vortex structure which resonated with the mode of the HSA between 7 and 9 kHz. Zhang et al (2010) investigated an effect of a flow diverter upstream of the actuator arm and a spoiler downstream of the actuator arm. They performed numerical calculations with models of an original commercial drive, a drive with the flow diverter and a drive with the flow diverter and the spoiler.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the flow-structure interactions in an air- or helium-filled hard disk drive geometry

2011

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The increased rotating speed of the hard disk drive (HDD) causes an unsteady flow field between each stack of disks and leads to flow induced vibration on the slider suspension unit (SSU). This flow induced vibration can reduce the positioning accuracy of the SSU and lead to failure to read or write data. Therefore, reduction of turbulence kinetic energy around the SSU is an important step to improve the performance of the HDD. Several modifications have been investigated in air to decrease the direct effect of unsteady flows on the SSU (e.g. spoiler, damper, or divider in the region upstream of the arm). However, these methods are not fundamental solutions for reducing the vibrations on the SSU. Since the HDDs currently in use are filled with air, helium was selected to compare the flow pattern due to the differing inertial property. To visualize the flow pattern, particle image velocimetry (PIV) measurements were performed at the inter-disk mid-plane between a pair of disks near the arm and the SSU. The geometry is an expanded 29 model simulating Seagate cheetah 2.5-inch drive. For both the air and the helium filled drives, measurements have been performed for two different locations of the SSU for two different angular velocities of 1,000 and 3,000 rpm, corresponding to 5,000 and 15,000 rpm in the commercial drive. The results reveal that the flow patterns of the air and the helium flow are quite similar. However, with respect to the turbulence intensity around the SSU, the helium flow shows a drastic decrease compared with that of the air flow, resulting in much reduced positioning errors. As such, helium-filled drives have merit and should be looked into.

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“…Numerical simulation on the air-flow induced vibration of actuator arm fixed at the disk middle diameter between the two disks in a commercially available HDD operating at 10 000 rpm were carried out by our group [8], [9]. Two different cases viz.…”

Section: Introductionmentioning

confidence: 99%

Flow-Induced Slider Vibration in a Functional Hard Disk Drive: Influence of Air Shroud

et al. 2009

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An air shroud is designed and placed within a commercially available hard disk drive operating at 15 000 rpm. Large eddy simulations of the turbulent airflow characteristics resulting from both the models, with and without air shroud, are carried out by assuming the read/write head is at the disk middle diameter. The numerical model consists of about nine million tetrahedral cells with the largest and smallest sizes of the cell volumes being 2.5 mm 3 and 0.35 mm 3 , respectively. The dynamic Smagorinsky-Lily model is employed to mimic the effect of small-scale eddies in the turbulent airflow. Numerically predicted airflow characteristics are compared against the LDA measurements and found to be in good agreement. The wind blowing on the surfaces of the head gimbals assembly is converted into aerodynamic forces and the resulting slider displacement in the off-track and out-of-plane directions are investigated. It is inferred that the disk drive model with air shroud results in a maximum of 44% and 10% less off-track and out-of-plane slider displacements, respectively.

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Mitigation of flow induced vibration of head gimbal assembly

Cited by 25 publications

References 11 publications

Airflow-Simulation by Voxel Mesh Method for Complete Hard Disk Drive Structure

Airflow-Simulation by Voxel Mesh Method for Complete Hard Disk Drive Structure

Experimental study of the flow-structure interactions in an air- or helium-filled hard disk drive geometry

Flow-Induced Slider Vibration in a Functional Hard Disk Drive: Influence of Air Shroud

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