Finite element analysis of hard disk drive vibration modes
(Laser Doppler vibrometry, being a non-contact and non-intrusive optical measurement method, has proven its worth as an ideal tool for conducting experimental modal analysis and FEM model verification operations on hard disk drive components. A high degree of importance has, in this regard, been attached to the rotating magnetic disks on the one hand and to the read/write unit with actuator, actuator arm and read/write head on the other. The undesirable vibrational properties of these components have a direct influence on a hard disk drive’s performance, reliability and service life.
The hard disk drive’s material and geometrical parameters are included in its FEM analysis. A scanning out-of-plane vibrometer measurement allows you to directly validate the model prediction for resonance frequencies and deflection shapes in a stationary condition and also shows you the deviations during operation that occur as a function of the rotational speed at the typical rotational speeds up to 15,000 rpm.
A Practical Example
3D modal test on the RW head: Scanning vibrometers that perform three-dimensional measurements and simultaneously capture both the in-plane and the out-of-plane parts of the movement are used to conduct modal analyses on the read/write unit. You can export the data derived from this process directly using the universal file format for the purpose of both modal analysis and model updating.