The study of empirical methodology to observe damping characteristics of various laminate composite plates

摘要

Modifying the stiffness of the structure is usually not a feasible solution to enhancing damping, since changing the stiffness effects the natural frequency changing and eventually the condition of resonance will be reached. Therefore, one of the recommendatory ways to reduce the response on structural elements is to improve damping characteristics. The objectives of this study are to present empirical methodology to detect damping characteristics of structural elements, and determine the optimal location of sensor to detect structural failure by analyzed data from both experimental and numerical analysis. Using orthotropic composite plates comprised of 977-2 Carbon fiber/IM7 epoxy, the natural frequencies of structural bending modes and damping ratio of the composite plates were experimented by free vibration test, and then comparison was made between the experimental results and the numerical analysis done by finite element method. The effectiveness of crack on a structure in damped free vibration was confirmed by the analysis using edge-notched composite plate. The results represented the natural frequency of a composite plate was consistent with changing sensor location, and showed good agreement for both experimental and numerical analysis.