Focal law design for phased array ultrasonic testing of CFRP based on finite element modeling

Abstract

The focal law of linear phased array ultrasonic testing of carbon fiber reinforced plastic (CFRP) laminates was studied based on finite element modeling. Two stacking sequences, [0] 40 and [45/90/-45/0] 10 , were considered and the focusing results were compared based on the calculation of transient acoustic field. It was found that the actual focal point was ahead of the preset location when the focal law was calculated with a constant velocity of 2980 m/s, and the focal depth of [0] 40 laminate was much smaller than that of [45/90/−45/0] 10 . To realize the focal law design, the time delay from each element to the preset focal point was acquired based on the finite element simulation and the focusing was obviously improved. The results were also verified by experiments. The differences were comprehensively discussed based on the wave propagation behavior in the elastic anisotropy and laminar structure.