Analysis of head disk collision for hard disk drives under shock excitations

The dynamical response of head disk system to a half sine pulse excitation is analyzed by means of numerical method according to the dynamical equations of head disk collision under the shock excitation for the Winchester type hard disk drive. When the head disk collision occurs, the peak acceleration of the shock pulse approximately follows a linear relationship with the inverse of the excitation duration. With the change of the excitation intensity and duration, the failure of a hard disk drive can be categorized into three modes, the performance degradation function failure, the local damage of disk surface and the structural damage of head disk system. The head disk collision can take place many times, whose locations may be at the trail of the slider or the front. The theoretical result agrees well with the experimental data.