اعتبارسنجی الگوی شکست نمونه آزمایش شده با دستگاه مبدل بار فشاری به کششی توسط نرم افزار FRANC2D و روش ناپیوستگی جابجایی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 مشاور مدیر عامل شرکت راهسازی و عمران ایران ،تهران، ایران

2 دانشکده مهندسی معدن، دانشگاه صنعتی همدان

3 مدیر عامل شرکت راهسازی و عمران ایران، تهران، ایران

4 کارشناس ارشد فنی،شرکت راهسازی و عمران ایران، تهران، ایران

چکیده

در این مقاله، دستگاه مبدل بار فشاری به کششی (CTT) معرفی می شود که با استفاده از آن می توان شکست کششی در نمونه ایجاد نمود. دستگاه تبدیل بار فشاری به بار کششی از 6 قسمت مختلف ساخته شده است. جزء شماره 1 و 2، ∪ شکل و ∏ شکل می باشند که از فولاد ضد زنگ ساخته شده اند. جزء شماره 3 و 4، دو فولاد ضد زنگ نیمه استوانه ای با ابعاد mm 60×mm75×mm10 هستند. جزء شماره 5 و 6، دو تیغه فولادی با ابعاد mm 20× mm 10× mm 190 می باشند. نمونه های بتنی مورد استفاده در این تست دارای مقطع مستطیلی و حفره مرکزی است. نمونه مورد آزمایش، دارای ابعاد mm190× mm60 ×mm 150 و حفره مرکزی دارای قطر mm 75 و ارتفاع mm 60 می باشد. نسبت قطر حفره به عرض نمونه برابر 5/0 است. این هندسه با استفاده از مجموعه ای از شبیه سازی ها توسط نرم افزار FRANC2D ، انتخاب شده است. نمونه های بتنی از ترکیب آب، ماسه ریز دانه و سیمان با نسبتهای %40، %30 و %30 آماده شده اند. دستگاه و نمونه بتنی در ماشین تک محوره قرار می گیرد. با تبدیل بار فشاری به بار کششی توسط دستگاه CTT، آزمایش کشش انجام شد. الگوی شکست رخ داده در نمونه آزمایشگاهی گویای شکست کششی است. به منظور اعتبارسنجی الگوی شکست نمونه آزمایشگاهی، آزمایش کشش توسط نرم افزار FRANC2D و روش ناپیوستگی جابجایی مرتبه بالاتر شبیه سازی شد. تطابق الگوی شکست نمونه آزمایشگاهی، مدل عددی FRANC2D و مدل عددی ناپیوستگی جابجایی مرتبه بالاتر بیانگر اعتبار دستگاه معرفی شده در ایجاد شکست کششی در نمونه می باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Validation of Failure Pattern in Sample Tested in Compression to Tensile Load Convertor Device Using FRANC2D and Displacement Discontinuity methods

نویسندگان [English]

  • Hadi Haeri 1
  • vahab sarfarazi 2
  • jalal bahrami 3
  • amir khosravi 4
1 Rahsazi & Omran Iran construction Company, Tehran, Iran
2 Department of Mining Engineering, Hamedan University of Technology, Hamedan,Iran
3 Rahsazi & Omran Iran construction Company, Tehran, Iran,
4 Rahsazi & Omran Iran construction Company, Tehran, Iran
چکیده [English]

In this paper, a compressive to tensile load convertor (CTC) device has been introduced which can be used for induction of tensile failure in specimen. This devise was consisted of 7 different parts. Parts number 1 and 2 which have U shape and П shape section have been made from stainless steel. Parts number 3 and 4 were made from two semi-cylindrical stainless steels with dimension of 10mm × 75mm × 60mm. Parts number 5 and 6 were made from two stainless steels with dimension of 190mm × 10mm × 20 mm. The concrete specimens used in this test have rectangle shape with internal pore. This geometry was gained from FRANC2D simulation outputs. The concrete samples has been prepared by mixing water, fine sand and cement by the ratio of 40%, 30% and 30%. The CTC device and sample were inserted in uniaxial test machine. The tensile test was performed by conversion of compression load to tensile load using CTC test. The tensile failure pattern occurred in the sample. For validation of experimental results, numerical simulations have been done using FRANC2D and high order displacement discontinuity method. The good accordance between failure pattern in numerical simulations and experimental test shows the validation of introduced device in induction of tensile failure in specimens.

کلیدواژه‌ها [English]

  • compressive to tensile converter device
  • tensile strength
  • Concrete
  • FRANC2D
  • displacement discontinuity method

 

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