Evaluation of Impact Damages in RTM Stitched Composites by Using Ultrasonic Multiple Imaging Techniques

摘要

Impact damages are important destroyed sources of RTM stitched composite structures in-service. With their applications in aerospace and aviation industries the attention to evaluation of impact damages were paid widely by specialists in these fields. The structural details and characteristics give the mechanism to evaluate nondestructively the impact damages. An ultrasonic multiple-scanning imaging approach based on special designed high resolution transducer and soft-electronic gate technique is developed to see the details of impact damages in RTM stitched composites. The experimental results show that echo pulse patterns give qualitative information about damages; C-scan imaging provides quantitative distribution of impact damaged area; B-scanning imaging offers possibility of seeing topologies of damages in impact zone and extending of damaged zone along depth of RTM stitched laminate. The surface dead-zone of the employed ultrasonic technique is close to 0.13mm.