TY - JOUR T1 - A novel vibration-based optimization technique for identifying elastic constant distribution and volume fraction index in functionally graded rectangular plates TT - تکنیک بهینه سازی نوین بر مبنای ارتعاشات برای شناسایی توزیع ثوابت الاستیک و توان کسر حجمی ورق‌های مستطیلی مدرج تابعی JF - mdrsjrns JO - mdrsjrns VL - 16 IS - 6 UR - http://mme.modares.ac.ir/article-15-244-en.html Y1 - 2016 SP - 245 EP - 254 KW - Functionally Graded Materials KW - Vibration analysis KW - Inverse method KW - Elastic constants KW - Drops Contact Optimization algorithm N2 - In this paper, a new inverse method has been presented for identifying the distribution of material properties and volume fraction index of rectangular functionally graded (FG) material plates. This method benefits from vibration analysis of FG plates accompanied by a novel and efficient meta-heuristic optimization algorithm called Drops Contact Optimization (DCO) algorithm, being proposed for the first time in this article. The presented algorithm relies on the initial population and mimics the behavior of water drops in different level of contacting successively with a fluid surface. Through using the second shear deformation theory and applying the Hamilton principle, the motion equations are derived and, subsequently, the natural frequencies of the considered FG plates are obtained. The outcomes relevant to considered different material phases and various length to thickness ratios are achieved and compared with those available in the literature. Making a comparative study of the obtained results with five well-known optimization algorithms confirms that the proposed DCO algorithm produces better performance in convergent speed and accurate characterization of FG materials. M3 ER -