Free Vibration of Laminated Composite Plate with a Central Hole

Abstract

Composite materials find a wide range of application, especially in weight sensitive structures like aircraft, spacecraft due to their high strength-to-weight ratio and high stiffness-to-weight ratio. Laminated plates used in these structures are often subjected to dynamic loads. This necessitates the study of buckling and vibrational characteristics of these plates. The presence of holes in the plates makes the analysis complex. Holes are provided for venting, conveyance, maintenance etc. The presence of holes may alter the nature of vibration of the plates. It is, therefore, important to analyze the vibration of laminated composite plates with holes. Also, the effect of various parameters, e.g. boundary condition, aspect ratio, hole-size, number of layers, fiber orientation etc. needs to be analyzed for a safe and stable design of structures. An orthotropic plate with symmetric fiber orientation was considered for this study. The material properties were fixed. The natural frequencies were computed for different boundary conditions, number of layers, hole-size, aspect ratio, and fiber orientation. The effect of these variables on the nature of vibration is analyzed and discussed. Also, the natural frequencies of a square laminated composite plate with holes of various geometries – circular, square, triangular and hexagonal were computed and compared. ANSYS 13.0 is used for the computation of natural frequencies.