Abstract:

Ultrasonic echo Ascan method was used to scan carbon/epoxy 3D braided composites.

Defects areas located by using ultrasonic scanning were anatomized microscopically to investigate

the relationships between the ultrasonic pulse wave characteristics and micromorphology of

defects. Based on the experimental identification method depended on wave analysis method,the

ultrasonic attenuation of 3D braided composites was discussed from the point of the distribution of

carbon filaments and the interfaces between carbon fiber bundles and resin. The experimental results

show that the characteristics of ultrasonic propagation and attenuation in the composites are

related to the microstructure and some defects within the 3D braided composites. The

characterization of ultrasonic Ascan signal can be used to nondestructive inspection and defects

assessment.

Key words: 3D braided composites, ultrasonic echo method, micromorphology of defects, wave analysis method, ultrasonic attenuation