شبیه‌سازی المان گسسته گسترش ترک در پوشش‌های ترد

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی مکانیک، دانشگاه گیلان، رشت، ایران

چکیده

پوشش دهی قطعات و اجزاء در صنایع مختلف برای بهبود خواص سطح  آنها انجام  می‌شود. در این بین ، پوشش‌های ترد در کاربردهایی نظیر افزایش مقاومت در برابر خوردگی و حرارت بسیار مورد توجه قرار  گرفته‌اند. مود آسیب غالب در این ساختارها، ایجاد و گسترش ترک است، از  اینرو بررسی رفتار شکست در این ساختارها از اهمیت  ویژهای برخوردار است. در این مقاله، از روش المان گسسته برای شبیه‌سازی فرآیند ایجاد آسیب اولیه و گسترش آن در ساختارهای شامل پوشش و بستر، به دلیل قابلیت بالای آن در  پیش‌بینی این فرآیند، استفاده شد. رفتار پوشش و بستر به صورت ترد الاستیک در نظر  گرفته شد و اثر پارامترهای اختلاف ضرایب الاستیک اجزای  تشکیل دهنده و ضخامت پوشش بر گسترش آسیب مورد بررسی قرار گرفت. نتایج نشان داد، در ساختارهایی که سفتی پوشش به مراتب  کمتر از سفتی بستر است، در  ضخامت‌های کم پوشش، مود غالب آسیب، ایجاد ترک و گسترش آن به داخل بستر است، در  حالی‌که با افزایش ضخامت پوشش، گسترش ترک به داخل و یا به موازات فصل مشترک بین پوشش و بستر اتفاق  می‌افتد. اما در ساختارهایی که در آن سفتی پوشش  بزرگتر از بستر است، بدون توجه به ضخامت پوشش، گسترش آسیب به داخل  بستر نفوذ می‌نماید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Discrete Element Method Simulation of Crack Propagation in Brittle Coatings

نویسندگان [English]

  • M. A. Ghasemi
  • Seyed Reza Falahatgar
Faculty of Mechanical Engineering, University of Guilan, Guilan, Rasht
چکیده [English]

Coatings are used in different industries in order to improve the surface properties in components and instruments. In some situations, such as improving the wear resistance of an instrument, brittle coatings have been considered. Dominant failure mode in these structures is crack initiation and propagation. So, investigating the fracture behavior of these structures is of great importance. In this paper, the discrete element method is used to simulate the crack initiation and propagation in coating/substrate structures. This method has a great ability to predict damage initiation and propagation in structures. For this purpose, a discrete element solver code is written by authors. Brittle elastic behavior is considered in coating and substrate and the effect of elastic mismatch in constituents of structure and the coating thickness in damage initiation and propagation were investigated. The results showed that in structures in which coating stiffness is less than substrate stiffness, in the case of the low thickness of the coating, damage appears as crack initiation and propagation into the substrate but, by increasing the coating thickness, the crack grows into or parallel to the interface. In structures in which the coating stiffness is greater than substrate stiffness, no matter to the coating thickness, the crack grows to the substrate.

کلیدواژه‌ها [English]

  • Coating/substrate structures
  • brittle coating
  • discrete element method
  • damage propagation
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