3D laser vibrometry point data and 3D Local interaction simulation approach data of a aluminium stiffened panel with and without disbonds

Lamb waves were induced in two 1.25m x 1.25m stiffened aluminium panels; one with a disbond, one without a disbond. Three excitation frequencies of 100kHz, 250kHz and 300kHz were used and measured using a Polytec 3D scanning laser vibrometer (PSV-500-M) at a sample rate of 2.56MHz. 5 excitation sites were used along the length of the midpoint between the edge of the panel and the stiffener which reduced the effects of edge reflections interacting with the stiffener and the first wave packet. The excitation was induced using a PANCOM Pico-Z transducer and excited using a MISTRAS Group Ltd micro-DISP system. 825 measurement points were measured at points across the face of the panel which had the stiffener attached. Retro reflective glass spheres were attached to the face of the panel to improve the back scatter of laser light, hence improving the received signal. The measured signals were averaged over 200 measurements at each point to improve the signal-to-noise ratio. The measured data is velocity data given in mm/s and accessed through Polytec PSV software. This can be exported in the software to .txt or universal files for further manipulation. Both in-plane and out-of-plane data was recorded. A representative model was also created using the Local Interaction Simulation Approach (LISA). Commercially available cuLISA3D software which interfaced with MATLAB 2012b. Only the inner section of the panels were modelled to reduce computational overheads. The model was created using the physical properties of aluminium using a global cube edge length of 0.5mm. The adhesive layer was omitted for simplicity in this model. The disbond was modelled by creating a reduction in stiffness which produce comparative results to the experiments. All excitation sites were modelled as point nodes, both in-plane and out-of-plane data was recorded.