نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا، دانشکده مهندسی مکانیک، دانشگاه بوعلی سینا، همدان، ایران

2 استاد، دانشکده مهندسی مکانیک ، دانشگاه بوعلی سینا همدان، همدان، ایران

3 استاد، دانشکده مهندسی مواد دانشگاه صنعتی شریف، تهران، ایران

چکیده

در مقاله حاضر، اثر درصد نانو‌ذرات خاک رس و کربنات کلسیم بر میکروسختی نانوکامپوزیت‌های پلی‌پروپیلن با انجام آزمون ویکرز مورد بررسی قرار گرفته است. برای مقایسه با نتایج تجربی، یک مدل سه بعدی اجزای محدود آزمون ویکرز نیز در کد آباکوس شبیه‌سازی شده است. به‌منظور پیش‌بینی تغییر شکل پلاستیک کامپوزیت پلیمری، از معیار تسلیم دراگر-پراگر استفاده شده است. ضرایب دراگر-پراگر با انجام آزمون‌های کشش و فشار به‌صورت مجزا تعیین شده و در مدل عددی وارد شده است. دو فرض جریان پتانسیل وابسته و غیر وابسته در شبیه‌سازی در نظر گرفته شده است و زاویه اتساع مناسب با حداقل کردن خطای تجربی و عددی محاسبه شده است. در ادامه مدل‌های تحلیلی ماکرومکانیکی و میکرومکانیکی به‌منظور پیش‌بینی تاثیر نانوذرات بر سختی پلی‌پروپیلن بررسی شده است. هرچند نتایج نشان می‌دهند که مدل‌های تحلیلی قانون مخلوط‌ها و مارش دقت مناسبی دارند (حدود 10 درصد خطا)، اما می‌توان با انتخاب زاویه اتساع مناسب در روش عددی، به جواب‌های بسیار خوبی رسید (کمتر از 2 درصد). علاوه بر آن مشاهدات تجربی نشان می‌دهند، افزودن خاک رس و کربنات کلسیم باعث افزایش مدول الاستیسیته، تنش تسلیم کششی و فشاری و همچنین میکروسختی پلی‌پروپیلن می‌شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental, analytical and numerical investigation of polypropylene nanocomposites microhardness

نویسندگان [English]

  • javad payandehpeyman 1
  • Gholamhossein majzoobi 2
  • Reza Bagheri 3

1 Department of Mechanical Engineering, Bu-Ali Sina University, Hamedan, Iran

2 Department of Mechanical Engineering, Bu-Ali Sina University, Hamedan, Iran

3 Department of Material Engineering, Sharif University of Technology, Tehran, Iran

چکیده [English]

In the present paper, the effects of nanoclay and nano calcium carbonate on polypropylene nanocomposites microhardness are assessed using Vickers test. Also, a 3D finite element model of Vickers test has been simulated by Abaqus code to compare to the experimental results. The Drucker-Prager yield criterion has been used to predict the polymeric composite plastic deformation. The Drucker-Prager parameters implemented in the numerical model are determined by a tension and a compression test separately. Two associative and non-associative plastic flow assumptions are considered and an appropriate dilation angle is derived by minimizing the error difference of experimental and the numerical results. Furthermore, micromechanical and macromechanical models are investigated to predict nanoparticles effect on the polypropylene microhardness.  Although the results show that analytical models including Marsh and rule of mixture models have suitable accuracy (about 10% error), excellent results (less than 2% error) can be obtained by selecting appropriate dilation angle value in the numerical method. Moreover, experimental evidences show that adding nanoclay and nano calcium carbonate increases elastic modulus, tensile and compressive yield stress as well as microhardness of the polypropylene

کلیدواژه‌ها [English]

  • Vickers microhardness
  • Drucker-Prager Criterion
  • Micromechanic Model
  • Macromechnic Model
  • Polypropylene Nanocomposites

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