Modeling of Thermal Sensor Response to Disk Asperities

A finite-element model was implemented to study the transient thermoelastic-plastic contact between a thermal asperity sensor and a thermal asperity on a disk in a hard disk drive. The temperature change of the thermal asperity sensor during contact with an asperity was calculated and converted into resistance change of the sensor using experimental measurements for the relationship between the sensor temperature and the sensor resistance. In addition, the effect of asperity material properties on the resistance change of the sensor was studied. The simulation results show that the resistance change of the sensor is a function of the bias voltage applied to the sensor, the friction coefficient between the sensor and the asperity, the disk velocity, and the contact interference between the asperity and the sensor.