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.

Further applications in data storage