Abstract:

Composite materials are replacing metals in many structural applications such as aerospace, transportation, novel and pressure vessels due to their high specific strength and specific modulus. The dynamic responses of these structures differ from that made of isotropic materials due to the orthotropic nature of individual layers of the laminate. Free vibration analysis is a part of dynamic analysis where the natural frequencies of the structure can be estimated. The composite structures may sometimes be provided with different types of holes for the purpose of assembling the components and units inside the structure, for passing the cables and control mechanisms, for inspection, maintenance and attachment to other units. The influence of the thickness parameter is inherent at higher modes of vibration. In addition, providing skew angle for plates alters the stiffness of the plate. The classical lamination theory is limited to very thin plates and other classical solution tools do not give closed form solutions due to the discontinuity in geometry, boundary conditions and materials. In such situations a finite element method which uses the three dimensional elasticity theory for the evaluation of stiffness matrices will give an approximate solution to the desired accuracy.

Description:

Materials, Elasticity, Vibration, Geometry, Element Method