Study on the flexoelectric characteristics in the sensing element of a duplex frustum pyramid

Recently, many researchers have studied to overcome some disadvantages of conventional sensing mechanisms. And the flexoelectric effect draw great attention as key to enhance the sensor performance especially in micro/nano scale. However, the relatively low flexoelectric effect in macro scale becomes a difficulty to commercialization. In this paper, in order to enhance the performance of sensor using the flexoelectric effect, the sensing element of duplex frustum pyramid is suggested as an alternative to the sensing element of single frustum pyramid. The flexoelectric characteristics for the duplex frustum pyramid, which is made of barium strontium titanate (Ba_0.65Sr_0.35TiO₃ - BST) ceramic, are investigated numerically. If the height, top surface, edge angle and flexoelectric coefficient of the single and duplex frustum pyramids are identical (H = 2 mm, θ = 45°, μ₁₁ = 100 μC/m and a = 1 mm), the total volume of the duplex frustum pyramid is about 60 % of the case of the single frustum one. Moreover, the charge output for the duplex frustum pyramid becomes nearly double of the sensing element of single frustum pyramid. Also, most of charge output develops in the neighborhood of the top and bottom surfaces it is much preferable to use the sensing element of duplex frustum pyramid rather than use the sensing element of single frustum pyramid as long as it is manufacturable.