Coupled Bending and Torsional Vibrations of Thin Composite Pipes with Structurally Unsymmetric Laminated Configurations.

Abstract

Composite pipes with structurally unsymmetric laminated configurations (SULC pipe) shows coupled deformations upon bending and torsion. Our previous study treated the static behavior of the SULC pipes, and this paper deals with their dynamic coupling behavior. The coupled bending and torsional vibration of a cantilevered SULC pipe with an eccentric weight at its free end is analyzed, neglecting the mass of the pipe and assuming that it is an undamped free vibration system with two degree of freedom, transversal and rotational displacements. It is found that the SULC pipe has an elastic principal axis apart from its geometric principal axis, and the vibration becomes uncoupled when the center of gravity of the eccentric weight is located on the elastic axis of the pipe. The effects of the fiber orientation angles and the eccentricity of the tip weight on the vibration behavior are also analyzed considering the dynamic center of rotation. The analytical results show good agreement with the experimental results.