Vibration-based Damage Identification of Sandwich Panels with Truss Core

A damage identification method, based on structural time domain dynamic responses and Teager energy operator, is presented for sandwich panels with truss core in the paper. The dimensionless structural dynamic responses, i.e., dimensionless velocity and displacement, are combined to construct the damage index. Application of the method on sandwich panels with truss core in the cases of single damage and multiple damages with different extents are conducted. Effects of some factors on the proposed method are discussed, including excitation location, excitation frequency, boundary condition, number of points N in Poincare maps. Experiments based on laser Doppler vibrometer are conducted to verify the effectiveness of the method. Numerical and experimental results show that the proposed method is effective in detecting both single damage and multiple damages with different extents. Excitation location plays a very important role in affecting the effectiveness of the method. Excitation frequency has little effect on the method, and there is a great selection space of excitation frequencies. Increasing the boundary condition constraint is beneficial for damage identification. As the number of points N increases, the damage index results also change. There is a reasonable number of points N for the damage identification of sandwich panels with truss core. Besides, Teager energy operator plays a very important role in eliminating the fluctuations caused by boundary condition or environment.