Integrated Design Of High Frequency Eddy Current System For Carbon Fiber Reinforced Plastic

Nowadays with the wide range of applications of carbon fiber reinforced plastic materials in practical engineering,it becomes more and more important to detect the damage of the structure.At present,there are many different kinds of nondestructive testing methods for carbon fiber composites.The eddy current testing method has widely recognized by academia and engineering with the characteristics of non-contact,with no need for coupling agent,and can be detected in the process of carbon fiber production.Carbon fiber composite has weak electrical conductivity,CFRP presents a degree of certain electrical conductivity,thus we can use eddy current testing technology to detect damage in CFRP.Due to the weak conductivity of carbon fiber composite materials,the detection frequency should be improved in order to obtain a higher detection sensitivity.In this paper,a set of high frequent electromagnetic eddy current testing system was be integrated to detect the common damage of carbon fiber composites.The software takes control of not only the mechanical arm clamp probe to achieve two-dimensional scanning,but also the hardware circuit to achieve signal generation,processing,transmission and so on.The testing system has a maximum frequency as high as 10 MHz and the testing frequency can be adjusted.The main content of this article contains: 1.Improve the hardware circuit automatic balance module,and complete the establishment of communication with the host computer protocol instruction format.2.Analyse the communication between the upper computer and the manipulator,and the control of the manipulator based on LabVIEW language.3.LabVIEW program has been used to design the holonomic testing system software,which makes hardware circuit control,manipulator motion control and data display and preservation procedures come true.The detection system can actualize the automatic scanning.4.Test plates of different types of damage were made,including crack,delamination and impact damage,and it is placed in the detection system for experimental verification.For the form of damage which is not easy to be observed,the results should be compared with the results of ultrasonic C scanning.The feasibility and practicability of the system are verified by the experimental results.