A mathematical model, based on Timoshenko beam assumption, for a rotating cylindrical shaft with cylindrical constrained layer damping treatment is developed. The model is developed for a shaft made of composite materials, and treated with a cylindrical constrained layer damping partially covering the length span of the shaft. The discrete equations of motion are developed using two methods: the finite element method and the assumed mode method. The developed equations are applied to study the effect of some geometric and material parameters on the flexural stiffness and damping of the shaft, with emphasis on the coverage length of the cylindrical constrained layer treatment. The effect of the spinning speed is also considered. Initial results indicate that, for the special case covered in this paper, the finite element method renders accurate results, while the assumed mode method engenders erroneous results. The results, in general, conclude that the partial cylindrical constrained layer damping treatment, suggested in this paper, is not promising.

No abstract

A novel hyperbolic composite coupling is proposed. In addition to enjoying the advantages of composite materials, the proposed coupling can be readily integrated with composite drive shaft into a single unit. A mathematical model of the coupling is developed based on the Timoshenko beam theory using the energy approach and the extended Lagrange’s equations. The corresponding discrete equation of vibration is obtained using the finite element method and solved for the natural frequencies using MATLAB. The dynamic characteristics of the coupling (Axial, torsional and bending natural frequencies) are studied in order to assess the merits and potential of the proposed coupling.

No abstract

No abstract