Fig. 1 The physical principle of the relation between the frequency-dependent refraction angle and the detection position on the MEMS-sensor array More

Fig. 2 An example of a calibration filter to remove inter-senor variations. Each MEMS-sensor recording is convolved with the corresponding filter. More

Fig. 3 Illustration of calibration process: ( a ) MEMS-sensor data before calibration and ( b ) after calibration. After calibration, the inter-sensor variations are resolved and a continuous signal is obtained. More

Fig. 4 Vacuum actuated Lamb source: ( a ) a side view of the actuator and ( b ) a top view of the actuator including the piezoelectric element in the middle between the three rounded bolts More

Fig. 5 An impression of the MEMS-sensor array: ( a ) a single module containing 32 MEMS sensors including corresponding hardware and ( b ) the four modules of the 128-element MEMS-sensor array mounted on an industrial robot More

Fig. 6 Verification of scaling rule of the dispersion curve More

Fig. 7 An impression of the GLARE 2 sample and the corresponding result of two different ultrasonic techniques. ( a ) The cross-section for the GLARE 2 sample contains four different configurations. In each configuration, only a single Teflon insert is shown in each configuration (the figure is no... More

Fig. 8 Fuselage skin that has been inspected: ( a ) picture of the curved panel, ( b ) anisotropic phase velocities estimated from measurements (line) versus phase velocities from finite-difference solution (squares) for different frequencies, ( c ) wavefield as measured on the MEMS array, ( d ) b... More

Fig. 9 An impression and results of the full-size fuselage demonstrator: ( a ) The setup of the full-size fuselage experiment with the MEMS-sensor array mounted on a translation scan system suspended on a trolley. The thickness maps for three different areas of the fuselage, ( b ) located near the... More

Fig. 1 Geometrical representation of the scattering of an incident wave in reflected and transmitted waves from a local region, with indication of the adopted discretization strategies in each region of the global-local approach [ 36 ] More

Fig. 2 Scheme of a through-transmission problem and typical subdivision of the waveguide into three subdomains in the global-local strategy More

Fig. 3 Structure of numerical implementation showing the difference between the parallel and serial code versions More

Fig. 4 Local domain mesh for h case. Different shades of gray indicate the different ply orientations. More

Fig. 5 ( a ) Computational time versus number of workers and ( b ) speedup versus number of workers for different problem sizes on the CFRP plate case More

Fig. 6 Phase and group velocity dispersion curves for ( a ) Aluminum plate and ( b ) CFRP plate More

Fig. 7 Damaged aluminum plate case study: ( a ) mesh and dimensions of the notched local zone, scattered energy spectra ( b ) for S0 mode incident and for ( c ) A0 mode incident, 2D spatiotemporal response of transmitted u x and u z displacements for a pure S0 mode incident in ( d ) pristine... More

Fig. 8 Damaged CFRP plate case study: mesh and dimensions of the ( a ) 2-ply and ( b ) 4-ply notched local zone, transmitted u x , u y , and u z displacements for pure S0 mode incident in pristine (solid lines) and notched (dashed lines) plates in ( c ) 2-ply and ( d ) 4-ply notched plates More

Fig. 9 Damaged CFRP plate case study: 2D spatiotemporal response of transmitted u x , u y , and u z displacements for a pure S0 mode incident in ( a ) pristine, ( b ) 2-ply, and ( c ) 4-ply notched plates More