non-destructive evaluation of glass-epoxy composite using impact-echo method

In this paper a new method for non-destructive testing or non-destructive evaluation is proposed for glass-epoxy composite. for this purpose, impact-echo was used to investigate thickness and integrity of composite plates. first of all, 4 composite plates were made of epoxy and fiber glass with different thicknesses (ranging from 8 to 12mm) which one of them contains predetermined internal flaw. afterwards impact-echo device was utilized to detect plate thickness and internal flaw. this process was modeled in anasys/lsdyna software and displacement-time graphs were obtained from the simulation. the obtained data were transferred from displacement-time to frequency domain graphs by means of fft. the thickness of the plates which were obtained from this simulation were in good agreement with experimental data. results represent that this method could be used for thickness measurement and flaw detection of epoxy-glass composites with an acceptable accuracy.