Dynamics of head-disk interface in hard disk drives during operational shock

Abstract

Dynamic responses of the head-disk interface (HDI) and other mechanical components, such as suspension, disk, ramp and base are critical to the mechanical robustness of a hard disk drive (HDD) during the operational shock (op-shock). The conventional op-shock simulations use the simplified linear spring model to decouple the structural and air bearing analyses. This paper presents a coupled field analysis method to integrate the air bearing model with the reduced structural model based on the finite element model of the full HDD, including the all major mechanical components for op-shock simulations. The dynamics of HDI and mechanical components in HDDs during the op-shock are then investigated by simulations. The effects of air bearing nonlinearity and the disk-ramp contact on the HDI responses to op-shocks are evaluated and understood by comparisons to the simplified linear model. The results reveal that conventional de-coupled simulation methods are no longer valid for the complicated nonlinear op-shock events, especially when the disk ramp contacts or slider-disk contacts are considered. The newly developed coupled-field method is suitable for such op-shock simulations by considering the complexity of the system nonlinearity.