Acoustic emission waveforms in composite laminates under low velocity impact

Ajit K. Mal, Frank Shih, Sauvik Banerjee, Tribikram Kundu
2003 Smart Nondestructive Evaluation and Health Monitoring of Structural and Biological Systems II  
Hidden damage caused by foreign object impact in a composite structure, if left undetected, can grow and lead to a catastrophic failure of the structure. Detection of impact events and characterization of the degree of damage caused by them, preferably in real time, would be extremely helpful in safe continued operation of composite structures. In this paper, low velocity impact experiments are carried out on AS4/3501-6 [0/90] 8S cross-ply graphite epoxy composite plates. An instrumented impact
more » ... instrumented impact testing system is used to record the contact force and the surface motion at locations away from the impact point. The response of the plate due to localized sources is calculated using a modified laminate theory providing detailed information on the relationship between the impact load and the signals generated by the load. For thin plates, the far-field response is dominated by plate guided Lamb waves. It is shown that the occurrence of an impact loading can be easily detected from the recorded signals. Delamination damage, if any, can also be determined through careful analysis of the recorded waveforms. Practical applications of the technique in structural health monitoring will require careful investigation and elimination of environmental noise.
doi:10.1117/12.484448 fatcat:votrwr6ykjb3zjggewl7pg2vmi