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Yayın Identification of the material properties of microisotropic materials(Springer Heidelberg, 2015-07) Kiriş, Ahmet; İnan, EsinThe vibration problem of a rectangular plate is considered in the present work. The main purpose here is to identify the upper bounds of the unknown material moduli of the microisotropic plate material. The frequency spectrum is obtained by extending Ritz Method to the present case. Three dimensional (3-D) vibration analysis is performed and some additional frequencies are observed among the classical frequencies as characterizing the microisotropic effects. These additional frequencies disappear by increasing values of microisotropic constants beyond some certain limits while the classical frequencies remain in the spectrum. The inverse problem is established for the identification of the upper bounds of the microisotropic constants as an optimization problem where an error function is minimized.Yayın Estimation of microstretch elastic moduli by the use of vibrational data(Springer, 2007) Kırış, Ahmet; İnan, EsinIn the present work, a nonlinear wave theory is used for the estimation of the material properties of a "microstretch" medium. For this purpose a thin plate is considered and triplicate Chebyshev polynomial series are used as admissible functions to ensure the satisfaction of geometric boundary conditions of the plate. The Ritz technique is applied to derive the frequency equation of the microstretch plate and an optimization procedure is performed by minimising the least square "distance" between computed natural frequencies from the energy method and measured natural frequencies. To realize the optimization procedure, a genetic algorithm is used to estimate the elastic moduli of microstretch medium.
