Propagation Characteristics of Ao Mode in a Metallic Beam Containing a Semi-infinite Crack

When Ao Lamb wave propagating in a sub-beam encounters the edge of a semi-infinite horizontal crack in a metallic beam, reflection, and transmission into the main beam and sub-beam takes place. Lamb mode transmitted from one sub-beam to the other is termed as "Turning Lamb Mode" (TLM). The variations in reflection and transmission factors of Ao Lamb modes, defined based on Fourier Transform and Wavelet Transform, when a horizontal crack is situated at different positions across the thickness of a beam were studies through numerical simulations. In addition to this, the power reflection and transmission ratios were also estimated. It was observed that the transmission and reflection characteristics of Ao Lamb mode strongly depend on the thickness ratio. It was also observed that the nature of variations in transmission factor, and power transmission coefficient of TLM with thickness ratio is different.