Test system for intermediate frequency eddy current of carbon fiber resin matrix composite

Abstract

The invention discloses a test system for intermediate frequency eddy current of a carbon fiber resin matrix composite. The system includes a signal generator module, an eddy current sensing unit, a lock-in amplifier module and a signal acquisition module. The eddy current sensor unit includes a transmission cable, an eddy current excitation coil, an eddy current testing coil and a coil control mechanism. The test system for intermediate frequency eddy current of carbon fiber resin matrix composite achieves properties and damage detection and judgment of CFRP composite material, and has the advantages of reasonable design, simple operation, high efficiency and low prices. The designed coil control mechanism adopts a flexible coil spring mechanism for pressing the coil, so as to fit the coil to the measured surface, and reduce the impact of the lift-off effect; at the same time, the design of each module has high sensitivity and strong detection capability on small signals.

Description

technical field [0001] The invention relates to a non-destructive testing system for a carbon fiber resin-based composite material, in particular to an intermediate frequency eddy current testing system for a carbon fiber resin-based composite material. Background technique [0002] The advanced carbon fiber resin-based composite material (referred to as "CFRP") with carbon fiber as a reinforcement is a new type of structural material that emerged in the mid-1960s. It has superior performance that other composite materials cannot match. Aerospace and other fields have been widely used. However, the heterogeneity and structural characteristics of CFRP composites make the internal defects of CFRP composite components and structural damage during processing and use unavoidable. Therefore, in order to ensure that CFRP composite components can meet the requirements of various fields, monitoring the internal quality of composite structures has received more and more attention...

AI Technical Summary

Problems solved by technology

High-frequency eddy current detection system is difficult to implement, because of the high frequency (usually reaching or exceeding 10MHz), high-frequency eddy current coils and signal processing and amplification circuits are difficult to design, and the signal is more susceptible to external interference and coil lift-off

Compared with the high-frequency ECT method, the medium-frequency eddy current detection method is much simpler to implement, but there are still problems of weak sensing signals and poor sensitivity. It is necessary to increase the sensitivity and amplification gain of the post-processing circuit as much as possible to achieve the extraction of weak and useful purpose of the signal

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