نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار، مجتمع دانشگاهی مواد و فناوری‌های ساخت، دانشگاه صنعتی مالک اشتر، تهران.

2 استاد، دانشکده مهندسی مکانیک، دانشگاه گیلان، رشت.

10.22068/jstc.2022.549100.1772

چکیده

‌به رغم ویژگی‌های منحصر به فرد برتر بالسا نظیر قیمت مناسب و خواص مکانیکی عالی، آب‌دوستی و حساسیت فراوان این ماده به جذب رطوبت، استفاده روزافزون از آن را در ساخت سازه‌های پیشرفته دریایی با چالش جدی مواجه نموده است. در صورت نفوذ رطوبت به پوسته‌های کامپوزیتی، ساختارهای ساندویچی مبتنی بر هسته بالسا دچار جذب آب شدید شده و انسجام ساختاری آن به مخاطره می‌افتد. در این مطالعه، به منظور ارتقاء خواص مکانیکی و همچنین مقاومت محیطی ساختارهای ساندویچی مبتنی بر هسته بالسا در مواجهه با شرایط محیطی مرطوب، ایده استفاده از چندلایه‌های الیافی فلزی به جای پوسته‌های کامپوزیتی پلیمری پیشنهاد شده است. بدین منظور، ساختارهای ساندویچی با هسته بالسا و دو نوع پوسته کامپوزیتی ساخته‌شده از الیاف شیشه/اپوکسی و چندلایه الیافی فلزی تحت آزمون‌های شرایط محیطی و مکانیکی قرار گرفتند. اهم نتایج به دست آمده از آزمون پیرسازی 100روزه در آب نشان می‌دهد که حداکثر میزان جذب آب در نمونه‌های ساندویچی با پوسته کامپوزیت الیاف شیشه/اپوکسی و چندلایه الیافی فلزی با لبه‌های آب‌بندی‌شده و دارای آسیب مصنوعی به ترتیب 106.71% و 83.32% است. همچنین با بررسی رفتار خمشی و کمانشی دو نوع ساختار ساندویچی مذکور، پیش و پس از فرایند پیرسازی رطوبتی مشخص شد که کاهش بار خمشی، سفتی خمشی و بار کمانشی بیشینه ناشی از پیرسازی رطوبتی در نمونه‌های ساندویچی با پوسته کامپوزیت الیاف شیشه/اپوکسی با لبه‌های آب‌بند به ترتیب 23.43%، 23.15% و 36.14% و برای نمونه‌های با پوسته چندلایه الیافی فلزی به مراتب کمتر و به ترتیب 13.57% و 11.06% و 16.14% بوده است.

کلیدواژه‌ها

عنوان مقاله [English]

Comparison of moisture aging effect on flexural and buckling behavior of two types of balsa core sandwich structures

نویسندگان [English]

  • Moslem Najafi 1
  • Reza Ansari 2

1 Faculty of Materials and Manufacturing Technologies, Malek Ashtar University of Technology, Iran.

2 Department of Mechanical Engineering, University of Guilan, Rasht, Iran.

چکیده [English]

Despite the unique superior properties of balsa such as reasonable price and excellent mechanical properties, the hydrophilicity and high sensitivity of this material to moisture absorption have posed a serious challenge to its increasing use in the construction of advanced marine structures. If moisture can penetrate into the composite skins, the balsa core sandwich structures will absorb a lot of water and compromise its structural integrity. In this study, to improve the mechanical properties and the environmental resistance of sandwich structures with balsa core against the moist environmental conditions, the idea of using fiber metal laminates instead of polymer composite skins has been proposed. For this purpose, sandwich structures with balsa core and two types of composite skins made of glass fiber/epoxy and fiber metal laminate were subjected to environmental and mechanical tests. The most important results obtained from the 100-day aging test in water show that the maximum water absorption in sandwich specimens with glass fiber/epoxy composite and fiber metal laminate skins having sealed edges and artificial damage is 106.71% and 83.32%, respectively. In addition, by evaluating the flexural and buckling behavior of two types of sandwich structures, before and after the moisture aging process, it was found that the reduction of flexural load, flexural stiffness and maximum buckling load due to moisture aging in sandwich specimens with glass fiber/epoxy composite skin with sealed edges were 23.43%, 23.15% and 36.14%, respectively, and for specimens with fiber metal laminate skin were much less, and 13.57%, 11.06% and 16.14%, respectively.

کلیدواژه‌ها [English]

  • Sandwich structures
  • Balsa core
  • Fiber metal laminates
  • Flexural behavior
  • Buckling behavior
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