تحلیل ارتعاشات آزاد پوسته ‏های مخروطی تقویت شده با نانولوله‏ های کربنی در محیط با دمای بالا

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده فنی و مهندسی، دانشگاه صنعتی قم، قم، ایران

چکیده

در این تحقیق، ارتعاشات آزاد پوسته‌های مخروطی کامپوزیتی تقویت شده با نانو لوله‌های کربنی در محیط با دمای بالا مورد مطالعه قرار گرفته است. توزیع نانو لوله‏‌های ‏کربنی در راستای ضخامت پوسته به دو صورت یکنواخت و مدرج تابعی درنظر گرفته شده است. اثر بارگذاری حرارتی به صورت تنش‌های اولیه در نظرگرفته، معادلات حاکم با استفاد از اصل همیلتون،‏ براساس تئوری کلاسیک و‏ روابط کرنش-جابه­ جایی غیرخطی فون کارمن بدست آمده است. معادلات مستخرج، با استفاده از رو‏ش گلرکین گسسته سازی شده است. در این تحقیق با استفاده از توابع تیر، فرکانس پوسته مخروطی به ازای شرایط مرزی مختلف بدست آمده است. درابتدا نتایج حاضر با نتایج موجود اعتبار سنجی شده است. سپس تاثیر پارامترهای مختلف ازجمله بارگذاری حرارتی، مقدار کسر حجمی، نوع توزیع نانولوله‏ های کربنی، شرایط مرزی مختلف و شرایط هندسی متفاوت بر روی فرکانس طبیعی سازه مورد بررسی قرار گرفته است. نتایج نشان از آن دارد که وجود بارگذاری حرارتی اولیه تاثیر قابل توجهی بر فرکانس طبیعی دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Free vibration analysis of nanotube-reinforced composite conical shell in high temperature environment

نویسندگان [English]

  • naghi aghaei
  • Mostafa Talebi Tooti
Mechanic,Engineering,Qom University of Technology,iran
چکیده [English]

In this research, free vibration analysis of functionally graded carbon nanotube reinforced composite (FG-CNTRC) conical shells subjected to high temperature environment is investigated. The material properties of FG-CNTRC are assumed to be graded through the thickness direction. Two kinds of carbon nanotube reinforced composites including uniformly distributed (UD), CNTs are distributed uniformly through the shell thickness, and functionally graded (FG), CNTs are graded with three different distribution, are considered. The effect of thermal loading is considered as an initial stress. Applying the Hamilton’s principle based on classic theory and considering Von Karman strain-displacement relation, the governing equations are obtained. The analytical Galerkin method together with beam mode shapes as weighting functions is employed to solve the equations of motion. The results are compared with those presented in literature. In addition, the effect of various parameters such as thermal loading, boundary conditions, and different geometrical conditions are studied. It is shown that the initial thermal stresses have significant effects on the natural frequencies and cannot be neglected. Moreover, the critical buckling temperature rise of the shells can be extracted from the presented diagrams of the fundamental frequency parameters verses the temperature rise.

کلیدواژه‌ها [English]

  • free vibration
  • Conical shells
  • Functionally graded carbon nanotube
  • Functions of the beam
  • Temperature
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