نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا، مهندسی مکانیک، دانشگاه تربیت مدرس، تهرا ن

2 استاد، مهندسی مکانیک، دانشگاه تربیت مدرس ، تهران

3 مهندسی مکانیک، دانشگاه آزاد اسلامی، تاکستان

10.22068/jstc.2020.120400.1629

چکیده

در این تحقیق، یک مدل تحلیلی به منظور بررسی ارتعاشات آزاد پانل-های ساندویچی مخروطی با هسته مشبک ارائه می شود. از یک روش تحلیلی- تقریبی معادل‌سازی جدید برای محاسبه پارامترهای سفتی معادل تقویت‌کننده‌ها استفاده می-گردد. در این روش، هسته مشبک با یک پوسته مخروطی کامپوزیتی معادل‌سازی می‌شود. تقویت‌کننده‌ها (هسته) به صورت تیر در نظر گرفته می‌شوند که قابلیت تحمل ممان‌های خمشی علاوه بر بار محوری را دارا می‌باشند. برای این منظور، در ابتدا با استفاده از آنالیز نیرو و ممان بر روی یک سلول واحد، پارامترهای سفتی معادل تقویت‌کننده‌ها تعیین می‌شوند و سپس به منظور دستیابی به سفتی کل سازه، با سفتی‌های پوسته‌ها جمع می‌شوند. با استفاده از روش گالرکین و تئوری کلاسیک دانل، معادلات حاکم بر پوسته ساندویچی استخراج و فرکانس‌های طبیعی ارتعاش به دست می‌آیند. به منظور اعتبار سنجی نتایج، یک مدل اجزای محدود سه بعدی نیز در نرم افزار آباکوس ساخته می‌شود. مقایسه نتایج توافق خوبی را نشان داد و اثبات کرد که مدل تحلیلی، از دقت کافی برای بررسی ارتعاشات سازه‌های ساندویچی مخروطی با هسته مشبک را داراست. نتایج حاضر جدید بوده و می‌تواند به عنوان مبنایی برای مطالعات آتی مورد استفاده قرار گیرد.

کلیدواژه‌ها

عنوان مقاله [English]

A novel smeared method for investigating the free vibrations of sandwich conical shells with lattice cores

نویسندگان [English]

  • Mehdi Zarei 1
  • Gholamhossein Rahimi 2
  • Milad Hemmatnezhad 3

1 Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

2 Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.

3 Faculty of Mechanical Engineering, Takestan Branch, Islamic Azad University, Takestan, Iran

چکیده [English]

In this study, an analytical model was presented for investigating the free vibrations of sandwich conical shells with lattice cores. A novel smeared method was employed to determine the stiffness contribution of the stiffeners. In this approach, the lattice core was approximated with an equivalent composite conical shell. The stiffeners were considered as a beam which support the shear loads and bending moments in addition to the axial loads. For this purpose, the stiffness contribution due to the stiffeners was firstly determined through the forces and moments analysis of a unit cell and then superimposed with those of the inner and outer skins in order to obtain the stiffness parameters of the whole structure. The governing equations were deduced using the classical shell theory of Donnell type and Galerkin method. In order to validate the analytical results, a 3-D finite element model was also created using ABAQUS software. Comparison of the results, revealed good agreements between the two approaches and demonstrated that the proposed analytical model is qualified enough to investigate the free vibrational behavior of sandwich conical shells with lattice cores. Results given are novel and can be used as a benchmark for future studies.

کلیدواژه‌ها [English]

  • Free Vibrations
  • Sandwich conical shell
  • smeared method
  • Galerkin method
  • FEM
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