Linear Material Coupling Effect on Structural Damping of Composite Beams and Blades

The current chapter presents the theoretical background for the damped dynamic analysis of composite beams and blades encompassing material coupling effects. The formulation includes composite material coupling effects, first in the crosssection stiffness and damping matrices and finally into the structural stiffness and damping matrices of the blade. In the following sections, new coupling damping cross-section terms associated with non-negligible ply stiffness and damping terms are formulated. In detail, this chapter consists of seven subsections. Firstly, a brief description of the developed damped beam finite element is presented. The second subsection reports the constitutive equations as well as the straindisplacement relations of the composite ply. Accordingly, the third subsection deals with the blade cross-section mechanics and the formulation of the respective linear stiffness, damping and mass terms of the cross-section. In the fourth subsection, building upon the damping mechanics, an extended beam finite element is developed capable of providing the stiffness and damping matrices of the structure, which contain new material coupling terms, essential for describing the structural dynamics response of composite beams and blades.