Airborne and Structure-Borne Transmission of High Frequency Fan Vibration in a Storage Box

In this paper, contributions of airborne and structure-borne vibrations to head positioning error of a HDD at high frequencies up to 10 kHz were investigated. The L8 array test was conducted with four two-level factors about vibration isolation between fans and HDDs: A) Removing bracket, B) Attaching foam on backplane, C) Filling foam in the next column, and D) Filling foam in the upper and lower slots. The test results showed there were less interaction between airborne and structure-borne vibration. Then, we set a model of fan vibration transmission and the model parameters were determined so that errors between the estimated and measured values were minimized. As the results, it was confirmed that about 80% of the power of PES was caused by the airborne vibration at the normal case.