Composite material bonding flaw detector is a device used for non-destructive testing of the bonding quality of composite materials. Its core function is to effectively and accurately identify defects in the bonding interface without damaging the material, thereby ensuring the safety, reliability, and service life of composite material products.
The essence of composite material bonding inspection is to analyze the continuity of the bonding interface through "energy penetration and reflection": when detection signals (ultrasonic, electromagnetic, infrared, etc.) act on the composite material, if the bonding interface is intact, the signal will penetrate the adhesive layer and reflect normally at the interface between the substrate and the adhesive layer; If there are defects such as debonding and bubbles, the signal will undergo abnormal reflection/scattering at the defect site. The instrument analyzes the amplitude, phase, propagation time and other parameters of the signal to determine the location, size and type of the defect.
The core difference between composite materials (such as carbon fiber) and metal material testing is that composite materials have characteristics such as anisotropy, low acoustic impedance, and complex layered structure. Therefore, it is necessary to optimize the detection frequency and signal processing algorithm in a targeted manner to avoid interference from the substrate itself on the detection of the bonding interface.
Detection Principle
Ultrasonic Testing
Pulse reflection method: emits high-frequency sound waves, locates defects by receiving reflection signals from defect interfaces, and combines A-scan display mode (with propagation time on the x-axis and reflection wave amplitude on the y-axis) to determine defect depth. Suitable for detecting delamination and debonding of laminated composite materials (such as carbon fiber reinforced plastics), as well as debonding of the skin and core materials of honeycomb structure composite materials.
Penetration method: Two probes (one transmitter and one receiver) are placed on opposite sides of the composite material. When the bonding quality is good, the receiving probe receives more energy. Otherwise, the opposite is true. It is suitable for detecting multi-layer composite materials with different acoustic impedances.
Resonance method: Suitable for detecting composite materials with similar acoustic impedance. When the bonding quality is good, the thickness obtained is the sum of two layers. When the bonding quality is poor, the thickness obtained can only be the first layer of the composite material.
eddy current testing
By inducing eddy currents in metal samples through energized coils, defects can cause changes in the distribution of eddy currents, which are then captured by the detection coil. Sensitive to small cracks, pores, and other defects in metal metal bonding layers, suitable for surface and near surface inspection, such as testing the bonding quality of metal composite materials (such as carbon fiber reinforced metal matrix composites).