Ultrasonic guided wave transmission through a geometry transition and NDE of composite-to-adhesive bond

Ultrasonic guided waves are important tools for inspection of adhesively bonded composites. Mode sensitivity to adhesive defects and conversion at geometry transition are considered when doing mode identification. Matching coefficients are used to prediction energy partition at the transition and compared with transmission coefficients. It verifies that matching coefficients need to combine with phase velocity matching to give reliable prediction. Finally, experiments are carried out using predicted mode-frequency combinations. Peak frequency shifts and amplitude reductions are identified as defect indicators.