Abstract: Many kinds of defects can be produced in the manufacturing, assembly and service stage of composite aramid paper honeycomb sandwich structure. The ability to identify defects can be affected by part status, material properties, defect types and non-destructive testing methods. According to the requirement of nondestructive testing for composite honeycomb sandwich structure, glass fiber skin honeycomb structure and carbon fiber skin honeycomb structure were tested by digital tap detection. On the basis of the traditional detection of shallow area defects (such as debonding, delamination, inclusion, weak adhesion), the deep buried volume defects (such as core material fracture and collapse) were also detected. The effects of skin type, defect type and defect topography on the contact time were discussed. The advantages and limitations of digital tap detection, ultrasonic pulse echo detection, through-transmission ultrasonic detection and X-ray digital radiography method were analyzed. The experiment proves that the digital tap detection technology can effectively detect the delamination, debonding, core material fracture and collapse defects in composite honeycomb sandwich structure, especial produced after curing.

Key words: honeycomb structure, tap detection, comparative analysis, core fracture, core collapse, composites