Ultrasonic Assessment of Cure Rate Effects in Bonded Honeycomb Structures

The effect of variations in cure temperature on fillet formation in adhesively bonded honeycomb structures has been defined in terms of fillet length, degree of cure and Tg of the cured neat adhesive. The results are correlated with predicted behavior based on ultrasonic NDE analysis prior to testing. The ultrasonic test method uses advanced pattern recognition analysis of attenuation and velocity data extracted from a multi-frequency Lamb wave propagated along the face sheet of the honeycomb. Laboratory applications of this test method are described.