A Study on the Flexoelectric Coefficient in the Frustum Pyramid Sensing Element with the Rigid Laminates at the Upper and Bottom Surfaces

In this study, the flexoelectric coefficients of a frustum pyramid sensing element with rigid laminates at the upper and bottom surfaces were investigated. The flexoelectric coefficients were estimated based on the results of 3D FEA stress analysis and quasi 1D stress field with respect to the identical strength of the incident signal. The RMS value and standard deviation of the ratio of flexoelectric coefficient (1D to 3D) were found to be 0.932 and 0.0005, respectively for varying input pressure. Additionally, the flexoelectric coefficient in the case of 3-D stress analysis was found to be 6.8 % larger than that in the case of quasi 1D stress analysis if the charge output of two cases are the same. Finally, to obtain a more reliable flexoelectric coefficient for a frustum pyramid sensing element, the flexoelectric coefficient obtained based on the results of 3D numerical stress analysis should be used.