Carbon fiber reinforced polymer (CFRP) is becoming increasingly important in component production in order to reduce weight and achieve high specific stiffness. Examples are the manufacturing of aircraft wings in aviation or body parts in the automotive industry. Delamination or cracks must be localized quickly during production or maintenance checks to avoid premature material fatigue. With high-frequency excitation of thin-walled CFRP panels, for example by piezo elements, Lamb waves (short-wave surface waves) are generated. These interact with defects in the material, which leads to variations in the wave propagation or to local resonances (Local Defect Resonance - LDR).

Optomet Scanning Laser Doppler vibrometers can detect the in-phase propagation of the waves at every measurement point on the material surface and thus visualize non-destructive defects in the material that are not visible to the naked eye. The internal signal generator can generate any waveform that can be used to excite the components, such as pulses or frequency sweeps. The OptoSCAN software is used to carry out the entire measurement from the setting of the measurement channels to the determination of the measurement points to the visualization and analysis of the measurement data in the frequency and time domain. Using the export function, the data can be exported in standard formats such as UFF, HDF5 and mat-files (MATLAB) and thus further processed.

By using the Optomet Scanning Vibrometer, defects introduced on the back of a CFRP plate are detected. The internal signal generator generates a rectangular pulse to excite a piezo actuator, which is attached to the CFRP plate. The waves propagating from the piezo element (bottom center) interact with the two defects, making them visible in the time and frequency domain through locally higher amplitudes (local defect resonance - LDR).