Prediction of the 3-D effective damping matrix and energy dissipation of viscoelastic fiber composites

A new method for calculating the viscoelastic damping matrix of fiber compo sites is presented in this paper. Firstly, on the lamina scale, the energy dissipation formula is obtained by using a damping matrix and the theory of linear anisotropic viscoelasticity. Then on the laminate scale, a 3-D effe ctive damping (loss) matrix is obtained by using the energy method. In term s of the 3-D effective damping matrix, the laminate energy loss and specifi c damping capacity (SDC) can be calculated by using the effective stresses and strains. The key to the application of the method lies in the derivatio n of the effective damping matrix from the constituent lamina damping coeff icients, stiffness coefficients and volume fraction and the laminate effect ive stiffness and compliance coefficients. Based on the effective damping m atrix method, the energy loss of viscoelastic fiber composites under arbitr ary loading conditions can be calculated. This method has the advantages of generality, simplicity and directness. Several numerical examples are give n to illustrate the accuracy of the model. (C) 2001 Elsevier Science Ltd. A ll rights reserved.