APPLICATION OF EXPERIMENTAL MODAL ANALYSIS TO IDENTIFY THE PARAMETERS OF THE MODEL OF LAMINATED CARBON FIBER REINFORCED PLASTIC
The calculation of modal characteristics (natural frequencies and vibration modes) of products made of polymer composite materials, necessary to exclude their resonance oscillations, requires reliable data on the mechanical characteristics of the material. The problem is a large (in comparison with isotropic materials) quantity of elasticity characteristics, and also in the fact that these parameters depend on a wide range of structural and technological factors. Data on the characteristics of materials, given in the literature, are often contradictory and require additional verification when carrying out responsible calculations. The purpose of this work is to develop a methodology for identifying models of elastic behavior of polymeric composite materials based on the results of experimental modal analysis using the example of laminated carbon fiber reinforced plastic. The object of investigation is a layered carbon fiber reinforced plastic based on an equally strong carbon cloth widely used in aircraft building. The method of scanning laser vibrometry is used for experimental determination of natural frequencies and modes of oscillations. For the numerical modal analysis, the finite element method is used. The material model is a layered composite with orthotropic linearly elastic layers. The task of identifying the material model is considered as the problem of minimizing the discrepancy between the calculated natural frequencies and the experimental ones. To solve it, the quasi-random search method is used. The developed method can be recommended for determination of parameters of material models for calculating modal characteristics of polymer composite products.