مطالعه ی آزمایشگاهی و عددی عرشه های هیبریدی فولاد-FRP تحت بارهای خمشی

نوع مقاله : پژوهشی اصیل (کامل)

نویسندگان
دانشکده مهندسی عمران و محیط زیست، دانشگاه تربیت مدرس
چکیده
در طی چند دهه­ی گذشته استفاده از مصالح نوین افزایش قابل توجهی در ساخت و ساز بسیاری از سازه­ها داشته­اند. در این پژوهش یک عرشه نوین ساختمانی ارائه شده و بصورت آزمایشگاهی و عددی مورد بررسی قرار گرفته است. در تمامی عرشه­ها از چسب وینیل استر برای اتصال پروفیلهای GFRP به یکدیگر استفاده شده است. در عرشه­های هیبریدی مقاطع سرد نورد توسط چسب به مقاطع GFRP و توسط تسمه­های فولادی به یکدیگر متصل شده­اند. برای تعیین مشخصات مکانیکی مصالح از آزمایش­های خمش سه نقطه­ایی، فشاری و کششی برای مصالح GFRP، آزمایش کشش برای ورق فولاد، و آزمایش کشش و برش برای چسب اپوکسی استفاده شده است. پس از انجام آزمایش­های تعیین مقاومت مصالح، ظرفیت خمشی چهار نمونه عرشه مورد بررسی قرار گرفته است. متغیرهای اصلی آزمایش­ عرشه ­ها شامل طول عرشه، اثر مقطع سرد نورد و تعداد مقطع­های GFRP بوده است. با بررسی نتایج آزمایشگاهی مشخص گردید که شکست ترد بین مقطع­های GFRP در ناحیه چسب (برای عرشه­ های فاقد مقطع فولادی) رخ داده است، خرابی­های موضعی قابل توجه بوده و جدایش بین لایه­ایی نیز در مقطع­های GFRP در بار نهایی مشاهده شده است. افزودن مقطع سرد نورد شده اثرات چشمگیری در بهبود ظرفیت خمشی و سختی عرشه­های کامپوزیت داشته­اند و باعث جلوگیری از جدایش در لایه­های چسب شده که در نتیجه باعث یکپارچگی عملکرد عرشه شده است. علاوه بر این افزایش شکل پذیری باعث بهبود قابلیت اعتماد عرشه­های هیبرید در مقایسه با عرشه های ساخته شده از FRP شده است. همانگونه که اشاره شد ظرفیت باربری عرشه ­ها نیز به میزان مناسبی افزایش یافته است. پس از انجام آزمایش­های ذکر شده، عرشه ­های آزمایش شده با استفاده از شبیه سازی اجزاءمحدود در نرم افزار آباکوس مدلسازی شده ­اند و نتایج بدست آمده از مدلسازی و آزمایش­های انجام شده با یکدیگر مطابقت مناسبی دارند. همچنین خرابی­های مشاهده شده در آزمایش­های انجام شده مشابه با خرابی­های پیشبینی شده در مدلسازی بوده است. پس از صحت سنجی نتایج آزمایشگاهی و عددی مطالعه پارامتریک در جهت پیش بینی تاثیر پارامترهای مختلف بر روی رفتار عرشه­ ها صورت پذیرفته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله English

Experimental and Numerical Evaluation of Hybrid Steel-FRP Floor Panels Under Bending Loading

نویسندگان English

S. Jami
H. Khezrzadeh
Faculty of Civil and Environmental Engineering, Tarbiat Modares University
چکیده English

In recent decades, new materials have had widespread applications in the construction industry. In the present research, a steel-FRP flooring system is proposed and tested. The implanted experiments are performed in two sections: at first, tests of constituent materials used in composite decks are done, and then full-scale tests of hybrid composite decks are performed. Mechanical tests, including three-point bending, compression, and tensile tests of GFRP profiles, tensile tests of steel plate, shear, and tensile tests of epoxy adhesives, are done with the aim of reaching mechanical properties. Next, flexural tests on four decks are performed. The main variables considered are the length of composite decks, the cold-formed steel channel effect, and the number of GFRP profiles. In examining the composite decks, the fracture between cohesive layers was observed, and damage localization and fracture in profiles occurred. It found that the use of the steel plate increases the stiffness and load-bearing capacity of the decks. The primary failure mode in the experimental work was deboning between profiles and adhesive fracturing in the decks without steel plates. In the decks which are used steel channels, the complete composite action of the structure was observed, resulting in suppressing the debonding phenomenon. The decks with cold-formed steel channels exhibit higher reliability as a result of their ductile behavior. After the tests of composite decks, the composite decks were modeled in the Abaqus software, and the results of the experiments and simulations were compared together. The results of numerical analysis have good agreement with experimental data.

کلیدواژه‌ها English

Hybrid Composite Decks
FRP composites
Composite Structures
Experimental Evaluation
Finite element analysis
Nonlinear Analysis
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