Eddy-current sensor for de-lamination detection on aerospace structures

• Main Author: Xu, Yunqing.
• Other Authors: Chen I-Ming
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechatronics
• Online Access: http://hdl.handle.net/10356/53447
• Institution: Nanyang Technological University

Carbon Fibre Reinforced Polymer (CFRP) is a unique polymer material that has high specific strength, high specific stiffness, good thermal stability, highly anisotropic and low density properties. Due to these advantageous properties, the usage of the CFFP material is extended to heavy industries such as aerospace, oil & gas, automotive, power and petrochemical industries. Due to its rising importance in those industries, a growing amount of research efforts are focusing on developing an effective inspection method for this material. Currently, the well-developed methods for defect inspection on CFRP material are X-Ray, ultrasonic, laser-ultrasonic and scanning tunneling microscope. These methods required bulky equipment to carry out the inspections. Among the Non-Destructive Testing (NDT) techniques, the Eddy current sensing technique offers a promising solution for delivering an effective yet portable inspection system. However, Eddy current sensing technique is only well established for inspecting conductive materials. Although CFRP material has certain electrical conductivity, this property is much less than those in the metallic material. In this project, the possibility of applying Eddy sensing technique on the CFRP material sorting and defects inspections are investigated. A working system is developed based on a unique sensing probe and signal conditioning circuitry. This system is used to realize the purpose of detecting different orientations of fibre and defects on CFRP specimens. In all the experiments, the combination of frequency and output voltage is varied in order to find out the most effective match for the best response. The results from experimental investigations have shown that the developed system can detect various fibre orientations and defects effectively.