Effects of multi experimental cycles on pressure/gap-impedance characteristic of coil made of carbon black filled silicone rubber composite

The pressure-impedance characteristic at the contact stage and the gap-impedance characteristic at the non-contact stage for the coil made of carbon black filled silicone rubber composite (i.e. composite coil) under the multi experimental cycles are studied. In each experimental cycle, there is a critical impedance for the composite coil. If the composite coil is at the contact/non-contact stage, the impedance is less/more than the critical impedance. The impedance changes monotonically with the variation in the pressure/gap at the contact/non-contact stage. Therefore, the impedance of the composite coil has the potential to be used to measure the pressure/gap at the contact/non-contact stage. However, there are deviations among the pressure/gap-impedance curves under the multi experimental cycles, which results in that the repeatability of the pressure/gap-impedance characteristic cannot fulfill the requirement of the sensor development. To solve the aforementioned limitation, the effects of the mutli experimental cycles on the pressure/gap-impedance characteristic have been investigated quantitatively. The results show that the pressure/gap-impedance characteristic tends to be stable with the increase of the number of the experimental cycles. Therefore, the repeatability of the pressure/gap-impedance characteristic can be improved to develop the pressure/gap sensor by applying multi pre-experimental cycles on the composite coil.