In this paper a new method for Nondestructive testing or Nondestructive evaluation is proposed for Glass-Epoxy composite. For this purpose, impact-echo is used to evaluate the properties of composite materials, detecting internal defects and thickness measurement. In the impact-echo method a steel ball impacts on a composite plate and generates stress waves or P-waves which will be transferred into the plate. The results show that impact response of the composite plate for dominant thickness frequency for measuring thickness and locating the defect is in agreement with the normal measurement. Results represent that this method could be used for thickness measurement and flaw detection of Epoxy-Glass composites with a reasonable accuracy. تفاصيل المقالة

In this paper, an Impact-Echo method has been used to numerically simulate low velocity impact of a steel ball on laminated composite plates in order to measure the plate's thickness. For the purpose of simulation, Ls-Dyna finite element code has been employed to express the behaviour of impact between steel ball and composite plates. Furthermore, a single node near the impact area has been chosen and its displacement was demonstrated during the impact time on a graph by the software. After that, displacement-time graph was transformed to amplitude-frequency domain graph by means of Fast Fourier Transform which was done by MATLAB software. The peak frequency was used to calculate the plate's thickness. The calculated thickness was verified by real plate thicknesses and this comparison shows an acceptable agreement between simulation and experimental results. تفاصيل المقالة