Ultrasonic Testing Of Bonding Quality Of Metal And Metal/Metal And Composite Materials

Nowadays,the bonding structure has been applied in the important parts of the aviation and spaceflight.There may be some defects and damages in the bonding structure during the period of service,Bonding quality testing consists of unglued defect detection and bonding strength,this article mainly used ultrasonic testing technique to test the quality of bonding structure.This article designed and fabricated an aluminum/aluminum and aluminum/adhesive composite material honeycomb structure block,and different adhesive thickness of aluminum sheet/cementing agent/aluminum plate structure sample with 2 mm thick aluminum plate and the ARALDITE 420 AB glue.Using the software named CIVA to simulate the ultrasonic testing of the bonding structure.By comparing the testing result with the 5MHz,10 MHz and 15 MHz frequency water immersion focusing probe to determine the frequency of the probe that is the best adapt to the thin layer of bonding structure detection.The simulation experiment result shows that the 15 MHz probe detection effect is the best.This article used ultrasonic water law characteristic imaging detection method and ultrasonic phased comparative analysis.The result of ultrasonic water law characteristic imaging detection showed that 15 MHZ frequency probe detection has the best effect;In addition,by comparing the interface on the adhesive layer and adhesive layer under the bottom of the interface and wave radiation imaging quality,the result shows that the adhesive layer interface imaging detection of defect has the best accuracy.The quality of the detection of imaging improved through the Hilbert transform of signal waveform.The use of ultrasonic phased array instrument to test the adhesive layer,because of the poor precision of instrument,the limited sensitivity of probe and material attenuation and so on,the tiny flaw detection cannot be detect efficiently and cannot detect the defects.The nonlinear coefficient of the unglued defect and good bonding area is big by the analysis on characteristics of ultrasonic bonding structure nonlinear.To measure the bonding strength of adhesive layer by the bonding specimen tensile stripping experiment and compared with ultrasonic testing results and thesample after stripping.The research result shows that the thickness 0.29-0.32 mm bonding structure of rubber has strong bonding strength.The result of flaws of the stripping sample and the ultrasonic water characteristic imaging detection is basically consistent(The size of the defect detection of relative error ? 5%).This article uses ultrasonic water immersion to obtain signal,The Hilbert transform to extract the characteristics of the imaging detection method can be used directly to metal/metal,metal/composite material detection,Using ultrasonic nonlinear coefficient can directly evaluate the quality of bonding structure.