An article presents the experience with the detection of composite damage by means of an ultrasound excitation system. The high frequency signal is modulated by the low frequency lockin frequency. For the selection of the carrier signal, the sample response was measured for the sweep excitation and the resonance of the sample was determined by STFT. Subsequently, the lockin method was used for detection. In some cases, it is possible to detect defects already in sweep excitation. The measurement results are presented on composite CFRP samples.

This paper was supported by VEGA 1/0795/16,  UJEP-IGS-2018-48-002-1 and UJEP-SGS-2018-48-002-2 and by firm ”TMV SS” Ltd. (Prague, Czech rep.) by borrowing the OTvis system.