Identification Mothod of Vibrational Damping Parameters for Laminated Composite Materials

An identification method of vibrational damping parameters for laminated composite materials is presented by using the finite element eigenvalue analysis. A shell element for unsymmetrically laminated composite materials is formulated with the first-order shear deformation theory. The vibrational damping model of fiber reinforced plastic plates proposed by Adams et al. is used to calculate damping ratios for idenification problems. The identification problem of vibrational damping parameters can be converged as a nonlinear optimization problem. Vibrational damping parameters of unidirectional laminae are identified by using the quasi-Newton method, so that damping ratios of laminated composite materials calculated by the finite element eigenvalue analysis may be agree with those measured by the vibration test. An numerical examples, vibrational damping parameters of unidirectional laminae are identified and compared with the experimental results