طراحی بهینه مقاطع فولادی کششی از طریق بهبود روابط آیین‌نامه در خصوص اصلاح ضریب تأخیر برشی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری دانشکده عمران، دانشگاه آزاد اسلامی واحد نور

2 استادیار دانشکده عمران، دانشگاه آزاد اسلامی واحد نور، ایران

3 گروه مهندسی عمران، دانشکده فنی و مهندسی، د انشگاه آزاد اسلامی واحد نور، نور.

4 استادیار، دانشکده ریاضی، دانشگاه آزاد اسلامی واحد نور.

چکیده

پدیده تأخیر برشی هنگامی رخ می‌دهد که تمام اجزای مقطع کششی در انتقال نیروی کششی سهیم نباشند، در نتیجه در نزدیکی اتصال عضو به ورق گاست تمرکز تنش رخ‌داده است و این پدیده موجب شکست مقطع می‌شود. این پدیده مدت‌هاست که در آیین‌نامه‌ها موردتوجه قرار دارد، لیکن ضوابط آیین‌نامه‌ای مورداستفاده تا حد زیادی محافظه‌کارانه بوده و به نظر می‌رسد که اصلاحاتی در مورد آنها باید صورت پذیرد. در این تحقیق تعدادی مقاطع قوطی با اتصال اصطلاحاً چاقویی بدون جوش برگشتی و اتصال از طریق دو بال و مقطع تسمه کششی به روش اجزای محدود با استفاده از نرم‌افزار ABAQUS بررسی و مدل‌سازی شده و ظرفیت عضو با استفاده از سطح مقطع خالص آنها به‌دست‌آمده است، دیده می‌شود که در این خصوص، رابطه آیین‌نامه تا حدودی محافظه‌کارانه است و برای این منظور، روابط بهبود یافتهای ارائه شده است. پارامترهای مورداستفاده شامل طول اتصال، برون محوری نیروی محوری و اندازه جوش هستند. نتایج نشان می‌دهند طول اتصال، ضخامت گاست و همچنین برون محوری تأثیر محسوسی بر ضریب تأخیر برشی داشته و در ادامه نتایج به‌دست‌آمده با پیش‌بینی‌های آیین‌نامه مقایسه شده و روابط جایگزینی ارائه گردید.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Optimal Design of Tensile Steel Members by Improving the Regulations of Codes Regarding the Correction of Shear Lag

نویسندگان [English]

  • Lida Shahbazi 1
  • Sepideh Rahimi 2
  • Mohammad Hossein Zadeh 3
  • Ramzan Rezaeyan 4
1 Department of Civil Engineering, Nour branch, Islamic Azad University, Nour, Iran
2 Department of Civil Engineering, School of Engineering, Islamic Azad University Nour Branch, Nour, Iran
3 Department of Civil Engineering, Nour branch, Islamic Azad University, Nour, Iran.
4 Department of Math science, Islamic Azad University Nour, Branch, Nour, Iran
چکیده [English]

The non-uniform stress distribution that occurs in a tension member adjacent to a connection, in which all elements of the cross section are not directly connected, is commonly referred to as the shear lag effect. This effect reduces the design strength of the member because the entire cross section is not fully effective at the critical section location. This phenomenon has long been taken into account in various structural codes, however the rules of the codes used are somewhat conservative and it seems that they need to be reviewed. In this research, a series of steel box section connected through two wings and plate sections were studied through finite element method using ABAQUS software, and the ultimate member capacity was obtained. It can be seen that in this regard the relationship between the rules is somewhat conservative and optimized relationships have been proposed to address this issue. Parameters used include connection length, axial force eccentricity, and weld size. The results show that the length of the connection, the gusset plate thickness and also the eccentricity have a significant influence on the shear latency coefficient.

کلیدواژه‌ها [English]

  • Shear Lag
  • Tensile members
  • Net cross section failure
  • Box section
  • Welded connection

مراجع

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