Imaging of sub-surface defect in CFRP laminate using A0-mode Lamb wave: Analytical, numerical and experimental studies

M S Rabbi; K Teramoto; H Ishibashi; M M Roshid

doi:10.1016/j.ultras.2022.106849

Imaging of sub-surface defect in CFRP laminate using A₀-mode Lamb wave: Analytical, numerical and experimental studies

Ultrasonics. 2023 Jan:127:106849. doi: 10.1016/j.ultras.2022.106849. Epub 2022 Sep 16.

Authors

M S Rabbi¹, K Teramoto², H Ishibashi³, M M Roshid⁴

Affiliations

¹ Department of Mechanical Engineering, Chittagong University of Engineering and Technology, Chattogram 4349, Bangladesh. Electronic address: rabbi@cuet.ac.bd.
² Department of Advanced Technology Fusion, Saga University, Saga 840-8502, Japan.
³ Wakayama College, National Institute of Technology, Wakayama 644-0023, Japan.
⁴ Department of Mechanical Engineering, Chittagong University of Engineering and Technology, Chattogram 4349, Bangladesh.

PMID: 36137467
DOI: 10.1016/j.ultras.2022.106849

Abstract

Lamb wave propagation in the anisotropic material is characterized by the prominent directivity of wave energy transfer governed by the fiber direction. Due to this anisotropic behavior, it is difficult to define the location of defects by using the arriving time of reflected signals. In this article, A₀-mode Lamb wave-based damage detection technique has been illustrated which can detect the overlapping region of incident and scattered wave in the vicinity of the finite defect region in CFRP composite plate-like structure. A 5-cycle Hanning windowed tone burst of 30 kHz has been allowed to propagate through a 2 mm thickness [0/90]_4S CFRP plate with subsurface cylindrical defect. In the near field region of the defect, the incoming and reflected wave overlaps and the dynamic shear strains of the out-of-plane displacement evaluated consequently. A covariance matrix is developed consisting of the shear strains. The proposed technique can detect the overlapping regions by measuring the determinant of covariance matrix, thus the image of the defect can be reconstructed. In this article, the analytical model of the proposed wavelet-based technique for the subsurface cylindrical defect is discussed and their physical meanings are investigated through numerical and experimental studies in a cross-ply laminate.

Keywords: A(0)-mode Lamb wave; CFRP Laminates; Damage detection; Image reconstruction; Shear strain.