The pulse width effect of single half-sine acceleration pulse on the peak response of an actuator arm of hard disk drive

For a head actuator assembly, its shock dynamic response and damage may be studied and assessed using vertical drop test simulation. The maximum relative deflection between the tip of the arm and the pivot can be used as an index of its response to shock. The pulse width effect on the peak response of the relative displacement of an actuator arm during a drop test was investigated by finite element method. The actuator arm was simplified as a single-degree-of-freedom (SDOF) system. It was found that for both the finite element analysis of the actuator arm, and the theoretical analysis of its simplified model as an SDOF system, when subjected to single half-sine acceleration pulses, the peak values of the maximum relative displacement occured at a certain frequency ratio, i.e., a pseudo-resonance phenomenon.