Experimental and numerical investigation of interlayer crack effects on the Free-vibration of corrugated-face sheet composite sandwich plates

Today, composite material and sandwich plate structures are used more and more due to the unique properties such as a high ratio of strength to weight, corrosion resistance and energy or sound absorption ability. Corrugating sandwich structures is an effective method to reinforce mechanical properties of the composite materials. In this paper, dynamic analysis of these corrugated structures was carried out for a desired performance in the vibratory condition. One of the most important damages in the composite material layers is an inter-layer crack and also the separation between two layers. Vibration analysis of the trapezoidal corrugated sandwich plate was accomplished with ANSYS software using the finite element method. Simulated sandwich plate is a new model of corrugated sandwich plate which has a soft corrugated foam core and a cover of composite layers made from epoxy/glass. In order to validate the vibration behavior of the simulated sandwich plate, the results of experimental modal analysis were compared to the finite element method. The geometry and location effects of inter-layer crack on natural frequencies of the plate were investigated. It was found that with increasing crack dimensions the natural frequencies of the plate decreases and also depth of crack causes decreasing the natural frequencies which are promising results compared to the other references. The changes in vibration characteristics of the sandwich plate can produce comprehensive data to be used in training and designing of the artificial neural network for a promising approach in fault detection and prediction field.