Application of Experimental Modal Analysis for Identification of Laminated Carbon Fiber-Reinforced Plastics Model Parameters

Modal characteristics (natural frequencies and vibration modes) estimation is a common way to avoid resonance vibrations in constructions. It requires reliable data about mechanical properties of the material. In the case, when the polymer composites’ determination of such characteristics is difficult (in comparison of isotropic materials), because of a greater amount of elasticity characteristics and their dependency on wide range of structural and technological factors. Also, most of the literature and open sources contain controversial data about composite material properties, and in case of crucial constructions calculations, it would be better to perform an additional experimental identification of these properties. The aim of this paper is to create elastic vibration model parameters identification method for polymer composites using experimental modal analysis. The object of research is laminated carbon fiber-reinforced plastic based on a full strength carbon material widely used in aviation. An experimental determination of natural frequencies and corresponding vibration modes was performed using 3D scanning laser vibrometry. Finite-element analysis was used for numerical determination of modal characteristics. The material model used in calculations is a laminated composite structure with orthotropic, linear, and elastic layers. Identification of parameters was performed as a minimization problem of discrepancy between natural frequencies for corresponding vibration modes obtained numerically and experimentally. The problem solving was performed using a quasi-random search method. The proposed method can be recommended for material properties determination required for a modal analysis of polymer composite structures.