ارتعاشات آزاد پوسته های استوانه ای از جنس مواد هدفمند بر روی بستر الاستیک تحت نیروی محوری، فشار جانبی و شرایط مرزی مختلف

نوع مقاله : مقاله پژوهشی

نویسندگان

1 مهندسی هوافضا، پژوهشگاه هوافضا، وزارت علوم، تحقیقات و فناوری، تهران، ایران

2 پژوهشکده سامان ههای حمل و نقل فضایی، پژوهشگاه فضایی ایران، تهران، ایران

3 دانشکده مهندسی هوافضا، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

در این مقاله ارتعاشات آزاد پوسته‌های استوانه‌ای از جنس مواد هدفمند تحت نیروی محوری و فشار جانبی، احاطه شده با بستر الاستیک به ازای شرایط مرزی مختلف با استفاده از روش حل گسترش موج بررسی شده است. خواص مواد هدفمند مطابق قانون توانی در جهت ضخامت تغییر می‌کند. بستر الاستیک از نوع بستر دو پارامتری پسترناک می‌باشد. معادلات حاکم بر پوسته استوانه‌ای بر روی بستر الاستیک تحت نیروهای مکانیکی مبتنی بر نظریه مرتبه اول برشی سندرز-کویتر با استفاده از اصل همیلتون استخراج شده‌اند. با فرض میدان تغییر مکان به صورت گسترش موج معادلات حاکم حل شده‌اند. بسامدهای طبیعی پوسته استوانه‌ای تحت شرایط مرزی مختلف، به دست آمده و با نتایج مراجع مقایسه شده‌اند. مشخص می‌شود که استفاده از میدان تغییر مکان به فرم گسترش موج به صورت یک روش مؤثر و قابل اطمینان عمل نموده و به ازای شرایط مرزی مختلف نتایج قابل قبولی ارائه می‌دهد. البته نشان داده می‌شود که به ازای شرایط مرزی مختلف و ابعاد هندسی پوسته، دقت روش گسترش موج نیز متفاوت است. همچنین با تکیه بر نظریه توسعه داده شده، اثرات شرایط مرزی مختلف، نیروی محوری، فشار جانبی و پارامترهای بستر الاستیک بر رفتار ارتعاشی پوسته استوانه‌ای از جنس مواد هدفمند مورد بررسی قرار گرفت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Free Vibration of, Functionally Graded Materials Cylindrical Shells on Elastic Foundation under Axial force, Lateral Pressure and Different Boundary Conditions

نویسندگان [English]

  • A. Hadi 1
  • S. Shakhesi 2
  • H. Ovesy 3
  • J. Fazilati 1
1 Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran
2 Space Transportation Research Institute, Iranian Space Research Center, Tehran, Iran
3 Aerospace Engineering Department, Amirkabir University of Technology, Tehran, Iran
چکیده [English]

Free vibration characteristics of functionally graded materials cylindrical shells surrounded by elastic medium under axial force, lateral pressure and different boundary conditions using wave propagation method are investigated in this paper. The material properties of functionally graded materials are assumed to be graded in the thickness direction according to the power law. The elastic medium is assumed as two-parameter Pasternak elastic foundation. Governing equations based on the first order shear deformation theory of Sanders-Koiter for the cylindrical shell resting on elastic foundation under mechanical loads are derived by using Hamilton’s principle. By assuming displacement field in wave propagation form, governing equations are solved. Natural frequencies of cylindrical shell under various boundary conditions are obtained and compared with the results in the literature. It is seen that using displacement field in wave propagation form, acts as an effective and reliable method and gives the acceptable results for various boundary conditions. Although it is shown that for different boundary conditions and geometry dimensions, accuracy of the wave propagation approach is different. In addition, based on the developed theory the effects of different boundary conditions, axial force, lateral pressure and elastic foundation parameters on vibration behavior of functionally graded cylindrical shell are investigated.

کلیدواژه‌ها [English]

  • free vibration
  • Functionally graded materials
  • Cylin‌drical shells
  • axial force and lateral pressure
  • Elastic foundation
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