Detection of Acoustic Emission Signal Due to Impact Damage of Composite Materials Based EMD

Drop-weight impact test and small-mass impact test were carried out on composite laminates. The contact force and AE signal were measured during the tests, and the correspondence between AE signals and damage were analyzed respectively. For the drop-weight impact test, the contact force dropped and the frequency of the AE signal increased suddenly when the delamination appeared. Then the AE signal was decomposed using empirical mode decomposition (EMD). The amplitude anomaly were found in the first several intrinsic mode functions (IMFs), which could be used as a signal to characterize damage.; In the small-mass impact test, the contact force and AE signal were investigated in the same way. Additionally, Fourier transform (FFT) was used to find whether there is delamination. Results reveal that when laminates suffers the drop-weight impact, AE signals, combined with EMD, can be used for real-time health monitoring, For the plates impacted by small-mass objects, AE signal, EMD and Fourier transform can be used to determine whether there is delamination in the laminate.