Noncontact Material Recognition and Thickness Measurement Using Coil-Shaped Carbon Nanotube Composite

The monitoring of thickness using intrinsically flexible sensors remains an underexplored area in advanced manufacturing. Numerous challenges persist, including the lack of systematic studies on the correlation between materials and thickness response. In this article, integrated experimental analysis and finite element simulation are combined to investigate thickness measurement using coil-shaped carbon nanotube composite. This article focuses on six nonferromagnetic metallic materials and demonstrates effective thickness measurement, and the results reveal distinct response characteristics of the sensing element across different materials. However, these variations do not alter the fundamental relationship between induced electromotive force (emf) and thickness, namely, an increase in thickness corresponds to a decrease in induced emf. Through experiments and simulations, the increasing conductivity will lead to the induced emf of the sensing element decreasing and the measuring sensitivity increasing. Leveraging the feasibility of material recognition and thickness measurement across diverse materials, this article proposes a solution for multimetal thickness measurement. This approach facilitates tailored suggestions and recommendations for various engineering applications.