Abstract
This study proposes a prediction method for modal damping ratios of a polymer-based composite structure with a complex microscopic structure by using finite element analysis. If the modal damping ratios are given in a linear vibration problem of solid, the frequency dependence of damping characteristic can be numerically analyzed by using a mode superposition method. However, it is difficult to calculate the exact modal damping ratios by theoretical means. Therefore we proposed a method to identify the damping ratios by using numerical analysis based on a mathematical homogenization method. Given that dynamic viscoelasticity of matrix type resin is measured in advance, the proposed method enables us to calculate the modal damping ratios of a composite material with a periodic microstructure. In order to verify the validity of this method, a numerical analysis and a vibration experiment of a CFRP rectangle plate was conducted. Calculated natural frequencies, modal shapes and modal damping ratios well agreed with measured, and thus the validity of this analysis method was confirmed in CFRP.
