Measuring Surface Curvature, using a Bimodal LC Resonant Sensor

This paper presents the use of bimodal resonance in LC resonators for the evaluation of the surface curvature particularly in pipes using the magnetic coupling coefficient between elements. The evaluation relies on the calculation of angular displacement between coils at different fixed separations, offering a promising technique for non-contact displacement measurements. The study investigates the relationship between bi-modal resonant frequencies and surface curvature by conducting parametrized
$3\mathrm{D}$
finite element models to optimise sensor design. Through experimental measurements on 3D-printed samples with varying angles and materials. A thorough exploration of sensor optimization is presented, focusing on parameters such as coil height and separation, demonstrating the trade-offs between these factors and sensitivity in curvature measurement. Finite element simulations and experimental validation provide crucial insights into the optimal design parameters for the sensor. Moreover, the paper discusses challenges associated with manual coil placement and proposes avenues for future research, including the development of more robust coil holder designs and automated placement systems to enhance measurement precision and reliability. The results show a minimum error of 1 % and maximum error of 10% of curvature evaluation when the diameter of the curvature varies from 40mm to 200mm and lays down the groundwork for further exploration in non-contact displacement measurement.