نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، مهندسی هوافضا، دانشگاه علم و صنعت ایران، تهران، ایران

2 استادیار،دانشکده مهندسی مکانیک، دانشگاه علم و صنعت ایران ، تهران، ایران

چکیده

روش المان محدود توسعه یافته (XFEM) یکی از قوی‌ترین روش‌های عددی در مدل‌سازی ناپیوستگی بوده و بر پایه المان محدود می‌باشد. در این روش با غنی‌سازی گره‌ها و افزایش درجات آزادی آن‌ها از 2 به 4 و حتی در شرایط خاص به 10 به‌طور مجازی و بدون نیاز به تطبیق مش با هندسه ناپیوستگی، امکان مدل‌سازی فراهم می‌شود. در المان محدود لزوم تطابق کامل لبه المان‌ها با لبه ترک، تغییر المان‌بندی در هر مرحله از رشد ترک را نیازمند است که روند تحلیل رشد ترک را با صرف وقت و محاسبات زیادی روبرو می‌کند. یکی از اهداف اصلی در این تحقیق بیان روشی نوین برای مدل‌سازی ساده‌تر رشد ترک خستگی و دستیابی به عمر سازه از طریق محاسبه ضرایب تمرکز تنش می‌باشد. با روش المان محدود توسعه یافته برای هر نوع ترک تنها با یک المان‌بندی ساده می‌توان نتایج مورد نظر را با دقت بالایی محاسبه نمود. در این تحقیق با قابلیت المان محدود توسعه یافته در محیط نرم‌افزار آباکوس، مدل‌سازی مود ترکیبی سه بعدی رشد واقعی ترک در ترمیم نامتقارن پنل، انجام شده است. در این روش تغییرات پارامترهای شکست در راستای ضخامت در لایه چینی‌های متفاوت بررسی شده است. نمونه‌ها در این تحقیق شامل رشد ترک در مود ترکیبی است. با بررسی نتایج XFEM حاصل از این تحقیق و نتایج FEM و تجربی تحقیقات گذشته، مشخص شد که نتایج روش XFEM خطای کمتری نسبت به نتایج تجربی دارند.

کلیدواژه‌ها

عنوان مقاله [English]

Mixed mode fatigue crack growth analysis of cracked aluminium panel repaired with composite patches using extended finite element method

نویسندگان [English]

  • sara ghiasvand 1
  • Bijan Mohammadi 2

1 Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran

2 Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran

چکیده [English]

Extended finite element method (XFEM) is one of the strongest numerical methods that its basis is finite element method. In this method, using of enriching the nodes and increasing of their degrees of freedom (from 2 to 4 or even upto 10) virtually and without verifying the mesh and geometry of discountinuty, can model the system. In FEM crack geometry must be align with mesh edges which needs changing meshes in every steps of crack propagation and take so much time and too many analysis. One of the main objectives in this study is the expression of a novel method for modeling fatigue crack growth more easily and achieve the life of the structure by calculating the stress concentration factors.  In this paper by using XFEM in ABAQUS, real 3D crack trajectory in single side repair has been simulated. Variation of fracture parameterin thickness direction of cracked panel with different patch lay-ups has been studied. In this paper, tests include mixed mode crack propagation. By examining the XFEM results of this research, FEM and experimental results of previous studies, it was found that the results of XFEM in comparison to experimental results have less error.

کلیدواژه‌ها [English]

  • fatigue
  • Composite patch
  • Extended Finite Element Method
  • stress intensity factor

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