نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجو کارشناسی ارشد، مهندسی مکانیک، دانشگاه تهران، تهرا ن.

2 دانشیار، مهندسی مکانیک، دانشگاه تهرا ن.

10.22068/jstc.2021.539345.1749

چکیده

در این مقاله تاثیر افزودن نانوذرات به ماده زمینه در بهبود استحکام کمانشی صفحات نانوکامپوزیتی پایه پلیمری از طریق مدل‌سازی اجزا محدود بررسی شد. نانوذرات از دو جنس نانولوله‌های کربنی و نانو‌رس با درصد‌های حجمی مختلف با توزیع تصادفی به ماده زمینه افزوده شد و خواص مکانیکی ماتریس تقویت شده از طریق شبیه‌سازی اجزا محدود به کمک المان نماینده حجم در نرم‌افزار آباکوس محاسبه گردید. در ادامه با کدنویسی پایتون، نانولوله‌های کربنی به‌صورت جهت‌دهی شده درون ماده زمینه توزیع گردید و مدول یانگ موثر برای جهت‌های افقی و عمودی به صورت جداگانه به‌دست آمد. با داشتن خواص مکانیکی ماتریس تقویت شده، بررسی بار بحرانی کمانش برای صفحات ساخته شده از نانوکامپوزیت‌های پایه پلیمری از جنس اپوکسی و الیاف تک جهته شیشه از طریق روش تحلیل مقادیر ویژه انجام شد. مقایسه نتایج حاصل از این پژوهش با نتایج پژوهش‌های پیشین تطابق خوبی نشان داد. با افزودن نانوذرات افزایش بار بحرانی کمانشی صفحه با افزایش درصد حجمی مشاهده گردید. در حالتی که الیاف وجود دارند، هنگامی که نانوذرات در راستای الیاف که همان راستای بارگذاری هست توزیع شدند، بار بحرانی کمانش افزایش بیشتری نشان داد. در حالت بدون وجود الیاف و تقویت صفحه پلیمری خالص، در حالت جهت‌دهی طولی نانوذرات بار بحرانی کمانشی در راستای محوری 55.3% افزایش یافت، اما برای توزیع تصادفی افزایش به میزان 14.2% بود. درنهایت مطالعه پارامتری بر اثر جهت‌گیری نانوذرات، نسبت منظری صفحه، بارگذاری در جهت عرضی صفحه، جنس و درصد حجمی نانوذرات بر بار بحرانی کمانش صفحات پلیمری صورت پذیرفت.

کلیدواژه‌ها

عنوان مقاله [English]

Investigating effect of Nano-additives orientations on buckling strength of polymeric Nanocomposite plates reinforced by CNT and Nanoclay

نویسندگان [English]

  • Mahdi Neghabi 1
  • Majid Safarabadi 2

1 School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.

2 School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.

چکیده [English]

In this article, the effect of adding nanoparticles into the matrix on improving the buckling strength of polymeric nanocomposite plates was investigated through finite element analysis. Two types of nanoparticles, including Carbon nanotubes (CNTs) and Nanoclays with different volume fractions (VF), were added randomly into the Epoxy matrix and mechanical properties of the reinforced matrix were estimated using simulation of a representative volume element (RVE). Moreover, a python script was generated to distribute CNT nanoparticles in aligned orientations and calculate the equivalent Young's modulus in horizontal and vertical directions. Afterwards, the critical buckling load of nanocomposite plates made of unidirectional glass fibers and nanoparticle reinforced Epoxy matrix were studied, using Eigenvalue analysis. Results were validated by previous studies and a very good agreement was obtained. In general, adding nanoparticles into the matrix led to increasing the critical buckling load with an increase of nano-additive’s VFs. When nanoparticles were dispersed aligned with fiber directions, which is the same as loading direction, a higher increase of critical buckling load was observed. For the case of reinforcing pure polymeric plates without fibers, when nanoparticles were aligned in the longitudinal direction, axial critical buckling load rose to 55.3%, whereas for the random distribution, it was increased by 14.2%. Finally, a parametric study was conducted to evaluate the effect of nanoparticle orientations, the aspect ratio of plates, transverse loading, type, and volume fraction of nano-additives on the critical buckling load of polymeric plates.

کلیدواژه‌ها [English]

  • Nanocomposites
  • Finite Element analysis
  • Nanoparticles distribution
  • Representative volume element
  • Linear buckling
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