Abstract    The aim of present study is to investigate the effect of various parameters such as length, thickness, density, shear modulus of the core and Young modulus of skins for various boundary conditions: clamped-free and simply supported. By applying the model of Khalili et al for frees vibration analysis of sandwich beams by using finite element methods. Where, the core density is taken on consideration. The flexural vibrations of beams are analyzed by the finite element method, using the stiffness and mass matrix of beam element with three degrees of freedom per node. The three first natural frequencies are calculated by using Matlab commercial software. A comparison is established between three different lengths for each configuration. There is a good agreement between the results obtained by the present study with the results obtained by Khalili et al.

Keywords    Length; finite element method; free vibration; frequency; sandwich

چکیده    هدف از مطالعه حاضر، بررسی اثر پارامترهای مختلف از قبیل طول، ضخامت، چگالی، مدول برشی از هسته و مدول یانگ از پوست برای شرایط مختلف مرزی، کلمپ-رایگان و ساده، با استفاده از مدل خلیلی و همکاران برای تجزیه و تحلیل ارتعاشات آزاد پرتوهای ساندویچ از روش المان محدود است. چگالی هسته مورد بررسی قرار می‌گیرد. ارتعاشات خمشی تیرها توسط روش المان محدود با استفاده از ماتریس سختی و جرم عنصر پرتو با سه درجه آزادی در هر گره مورد تجزیه و تحلیل قرار می‌گیرد. سه فرکانس طبیعی برای اولین بار با استفاده از نرم افزار تجاری Matlab محاسبه می شود. برای هر پیکربندی، مقایسه‌ای بین سه طول مختلف انجام می‌شود. توافق خوبی بین نتایج به دست آمده از مطالعه حاضر با نتایج به دست آمده توسط خلیلی و همکاران وجود دارد.

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