Shear stress detection in an elastic layer by a piezoelectric polymer tactile sensor

A polyvinylidene fluoride (PVDF) sensor sandwiched between two elastic layers fixed to a rigid foundation is shown to be able to resolve a shear stress component produced by loading the upper layer´s surface with a rigid indenter. When the measured charge response of the sensor is compared to that predicted by analytical solution of the corresponding axisymmetric elastic contact problem, a significant qualitative agreement between the two responses results. The experimentally determinated sensitivity, on the other hand, is found to be higher than that predicted analytically. Possible causes of this discrepancy are discussed