Numerical Analysis of Lamb Wave Propagation in Composite Plate With Different Fiber Orientation Angles - Acoustic Emission Approach

This paper aims at numerical finite element (FEM) research of guided Lamb waves propagation in multidirectional composite plates. All simulations were conducted in the Abaqus/CAE software by using the dynamic/explicit solver. The material considered in this work was carbon/epoxy composite laminate with [90 degrees/0/0/0/-0/-0/-0/90 degrees] stacking sequence where 0 set was equal 0 degrees, 30 degrees, 45 degrees, 60 degrees and 90 degrees. The main goal of the analysis was to evaluate the influence of fiber orientation angles 0 on propagation behavior of the separate symmetric S0 and asymmetric A0 Lamb wave modes. Numerical model was created by using the C3D8R brick element. The Lamb waves were generated by using concentrated force with 200 kHz frequency. The acoustic signal generated by travelling wave was registered at two nodes that representthe acoustic emission sensors. Obtained results were presented in tabular form where separate mode velocities were collected and on the normalized displacement versus time plots depicted registered wave sig-nals. In addition, the contour diagrams and through-thickness deformations plots were created to present behavior of the extensional and the flexural modes. The greatest value of the S0 mode velocity was obtained for unidirectional laminates whereas the lowest for composite plate with 45 degrees fiber orientation angle. The asymmetric mode found to generate slightly greater deformation of plate in XZ plane than the symmetric. Recognition of the Lamb wave behav-ior in multidirectional laminates will allow to better planning the experimental acoustic emission tests.