اثر شکل‌شناسی سلول بر جذب انرژی اسفنج لاستیک نیتریل

نوع مقاله: پژوهشی

نویسندگان

تهران، دانشگاه صنعتی مالک اشتر، مجتمع دانشگاهی مواد و فناوری‌های ساخت، صندوق پستی 1774-15875

10.22063/jipst.2021.1777

چکیده

فرضیه: ظرفیت جذب انرژی زیاد اسفنج لاستیکی متغیر مهمی است که به‌دلیل تغییرشکل‌های فشاری بزرگ ساختار سلول، به‌عنوان ملاک طراحی مورد توجه طراحان قرار می‌گیرد. در این پژوهش، رفتار جذب انرژی اسفنج لاستیک آکریلونیتریل بوتادی‌ان (NBR) با چگالی‌های متفاوت بر اساس متغیرهای کارایی و آرمانی مطالعه شده است.
روش‌ها: اسفنج‌های سلول‌بسته NBR  با چگالی‌های 0.51، 0.63، 0.72 و 0.79g/cm3  و تغییر مقدار آمیزه در حجم ثابت قالب تهیه شدند. شکل‌شناسی و خواص فشاری اسفنج‌ها به‌ترتیب با میکروسکوپی الکترون پویشی (SEM) و آزمون فشاری بررسی شدند.
یافته‌ها: بررسی شکل‌شناسی سلول نشان داد، با کاهش چگالی اسفنج، قطر متوسط سلول بزرگ‌تر، تعداد سلول‌ها در واحد حجم کمتر و توزیع اندازه سلول ناهمگن‌ می‌شود. در آزمون فشاری با کاهش چگالی از 0.79g/cm3 به 0.51g/cm3  تنش مسطح از 750kPa  به 246kPa  و تنش متناظر با بیشینه کارایی از  1.13MPa به 0.27MPa  کاهش می‌یابد. در محدوده تنش‌های کم 0.3MPa ، جذب انرژی اسفنج با کاهش چگالی از 0.79g/cm3  به 0.51g/cm3 به‌ترتیب 0.03  و 0.009MJ/m3 تغییر می‌کند. در نتیجه در محدوده تنش‌های کم، اسفنج‌های با چگالی کمتر جذب انرژی بیشتری را نشان می‌دهند. در حالی که در محدوده تنش‌های زیادتر اسفنج با چگالی بیشتر جذب انرژی بیشتری دارد. به‌عنوان مثال، در محدوده تنش  1.3MPa، جذب انرژی اسفنج با چگالی‌های 0.51 و 0.79g/cm3  و به‌ترتیب 0.88 و 0.1MJ/m3  است. بنابراین، ظرفیت جذب انرژی اسفنج به چگالی و محدوده تنش وابسته است که حداکثر تنش مجاز اسفنج بر اساس چگالی آن تعیین می‌شود.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of Cell Morphology on Energy Absorption of Nitrile Rubber Foam

نویسندگان [English]

  • Javad Toulabi
  • Mohammad Khabiri
  • Mohammad Reza Pourhossainy
  • Mohamoud Razavizadeh
  • Milad Saadat Tagharoodi
Faculty of Materials and Manufacturing Technologies, Malek Ashtar University of Technology, P.O.Box 15875-1774,Tehran, Iran
چکیده [English]

Hypothesis: High energy absorption capacity of rubber foam, during the large compression deformations of cell structure, is an important variable that is considered by engineers as a design criterion. In this respect, the energy absorption behavior of acrylonitrile butadiene rubber (NBR) foam with different densities was studied by efficiency and acutest parameters.
Methods: The closed cell NBR foams with densities of 0.51, 0.63, 0.72 and 0.79 g/cm3 were prepared by changing the amount of compound in the equal volume of the mold. The cell morphology and compressive properties of the foams were analyzed by scanning electron microscopy (SEM) and compression tests, respectively.
Findings: The cell morphology analysis has indicated that by decreasing the foam density, the average cell diameter becomes larger, the number of cells per unit volume decreases and the cell size distribution becomes heterogeneous. In the compression test, by decreasing density from 0.79 to 0.51 g/cm3, the plateau stress decreases from 750 to 246 kPa and the corresponding stress with the maximum efficiency decreases from 1.13 to 0.27 MPa. In the low stress range, 0.3 MPa, by decreasing density from 0.79 to 0.51 g/cm3, the energy absorption of foam changes from 0.39 to 0.009 MJ/m3. As a result, in the low stress range, lower density foams show more energy absorption. While in the high stress range, higher density foams absorb more energy. For example, in the 1.3 MPa stress, the energy absorption of foams with the density 0.51 g/cm3 and 0.79 g/cm3 is about 0.88 MJ/m3 and 0.1 MJ/m3, respectively. Therefore, the energy absorption capacity of the foam depends on the density and stress range, which determines the maximum allowable stress of the foam based on its density.

کلیدواژه‌ها [English]

  • rubber foam
  • nitrile rubber
  • energy absorption
  • efficiency parameter
  • ideality parameter
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