Numerical and experimental study of the effect of an edge crack on the vibration characteristics of UD and quasi-isotropic GFRP cantilever composite beam

The fiberglass-reinforced polymer is the most widely used composite because of its low cost and easy availability in the market. Fiberglass reinforced polymer is used for structural and semi-structural body parts of automotive. The presence of a crack in a composite laminate subjected to dynamic loading has an adverse effect on the stiffness and the vibration properties of the Alteration of undesired vibration properties or response of the composite may cause a resonance that resulted in a catastrophic failure of the structure. In this paper, the free vibration analysis of edge-cracked glass fiber-reinforced polymer laminate was studied using numerical and experimental methods. Specimens were prepared using vacuum bagging assisted hand layup method. ASTM E756 was used for free vibration analysis. Experiments were conducted using unidirectional E-glass fiber/epoxy laminated beam specimens with pre-defined cracks. The effect of crack depth and crack location on the natural frequencies of unidirectional [04]s and quasi-isotropic [0, 90, 45, -45]s laminated beams investigated for a cantilever beam. The obtained results from numerical analysis using ABAQUS were experimentally validated. Results showed that the natural frequencies were different for unidirectional laminate and quasi-isotropic laminate and it indicates the vibration properties of composite material depend on fiber arrangement. For both UD and QS laminate crack decrease the natural frequency. From the analysis the natural frequency decrease for an increase of crack depth. For both UD and QS laminates the location of the crack affected the natural frequency. The numerical results are in good agreement with the experimental analysis.