مدل سازی عددی عملکرد اتصال دهنده پیچ زیر بار برشی در LVL

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دکتری دانشگاه تهران

2 استاد گروه علوم و صنایع چوب و کاغذ، دانشکده منابع طبیعی دانشگاه تهران

3 استاد دانشگاه تهران

چکیده

اتصال‌ها یکی از مهم‌ترین قسمت‌ها در طراحی مهندسی سازه هستند، چون مبنای شکست‌های سازه‌ای می-باشند. بنابراین تولیدکنندگان علاقه دارند که از کفایت استحکام اتصال‌های موعود در سازه اطمینان حاصل کنند. تحلیل عددی روشی برای یقین حاصل کردن از برآورد استحکام اتصال است. در این پژوهش مدل‌سازی عناصر محدود برای ارزیابی عملکرد اتصال‌های ساخته شده با پیچ و اعضا از ال وی ال زیر بار برش موازی و عمود بر لبه عضو اصلی به‌کار گرفته شد. اتصال آزمونی با پیچ دارای قطر 2/4، 5 و 6 میلی‌متر ساخته شدند. از نرم افزار ANSYS برای شبیه سازی اتصال‌ها جهت ارزیابی مقادیر تنش ناشی از اعمال بار، استفاده شده است. نتایج نشان داده‌اند که بیش‌ترین تنش در سوراخ پیش ساخته عضو اصلی اتصال و در میانه محور پیچ اتفاق افتاده است. این مقدار تنش بالاترین نرخ اتفاق را وقتی داشته‌ است که بار به موازات لبه عضو اصلی اتصال وارد شده بود. مد شکست در اتصال‌های آزمونی در نقاط حداکثر تنش‌ به شکل لهیدگی تکیه‌گاهی و زنگی شکل مشاهده شد. مشاهدات به دست آمده نشان داده‌اند که اتصال‌ها زیر بار عمود بر لبه به نسبت عملکرد بهتری داشتند. ظرفیت تحمل تنش اتصال زیر بار موازی با لبه عضو اصلی با افزایش قطر پیچ کاهش می‌یابد، در حالی‌که در بارگذاری عمود بر لبه این ظرفیت با افزایش قطر پیچ فزونی دارد. چون توافق خوبی بین مشاهدات تجربی و نتایج حل عددی مشاهده می‌‌شود، این روش برای تحلیل و پیش بینی شکست اتصال‌ها در سازه مبلمان، توصیه می‌شود.

کلیدواژه‌ها

عنوان مقاله [English]

Numerical modeling of screw connector performance in LVL under shear loading

نویسندگان [English]

  • Mosayeb Dalvand 1
  • Kambiz Pourtahmasi 2
  • Ghanbar Ebrahimi 3
1 Writer
2 Professor, Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran
3 Professor, Department of Wood & Paper Science and Technology Faculty of Natural Resources University of Tehran
چکیده [English]

Joints are one of the most important parts in engineering design of structure, since they are basis of structural failures. Therefore manufacturers are interested in to make sure that strength of proposed joints in structure is sufficient. Numerical analysis is an assuring method for joints strength assessment. In this study, finite element method modeling was applied to evaluate performance of screw connected joints with Laminated Veneer Lumber (LVL) members, under shear load, applied parallel and perpendicular to edge of side member. Test joints were made with screw, having diameter range of 4.2, 5 and 6 mm. ANSYS software was used to simulate joints for evaluating value of stress history resulting from applied load. Results have shown that the highest strength has occurred in pilot holes in main member and middle of screw’s shank. These values of stresses had higher rate when joint was loaded parallel to the edge of side member. Modes of failure were observed in test joints, bearing and bell shape, at points where the highest stresses were generated. Collected data have indicated that joints under perpendicular load to the had rather better performance. Stress carrying capacity of joint under parallel load to the edge of side member decreases with increase in diameter of screw, while in perpendicular loading, it increases with increasment of screw diameter. Since good agreement is seen between experimental data and numerical results, this method is recommended for analysing and predicting failure of joints in furniture structures.

کلیدواژه‌ها [English]

  • LVL
  • Numrical modeling
  • Shear load
  • Screw
  • finite element method
  • Stress

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نشریه جنگل و فرآورده های چوب
دوره 74، شماره 3
آذر 1400
صفحه 357-369

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