بررسی رفتار پایداری و حساسیت به ناکاملی سازه‌های فضاکار فرم آزاد دو گنبدی

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه صنعتی سهند

چکیده

امروزه فرم­های آزاد توجه اکثریت طراحان را به خود جلب نموده است، به طوری که کاربرد فرم­های آزاد در طراحی سازه­ها افزایش یافته است. امروزه برای طراحان محدودیتی وجود ندارد که فقط از فرم­های هندسی متداول در طراحی­های خود استفاده کنند. فرم­شناسی، آزادی گسترده­ای به طراحان برای درک نسل جدیدی از فرم­ها می­دهد. این نسل جدید فرم­ها، امروزه فرم­های آزاد نامیده می­شوند. فرم­های آزاد به سطوح با انحنای مضاعف اطلاق می­شوند که مستقل از گروه فرم­های محدود شده از نظر هندسی و یا فرم­های محدود شده از نظر مکانیکی می­باشند. در این مقاله، رفتار سازه­های فضاکار فرم آزاد دو گنبدی با استفاده از نرم­افزار المان محدود مورد بررسی قرار می­گیرد. جهت صحت­سنجی مدل­سازی، نتایج مدل المان محدود با نتایج نمونه آزمایشگاهی مورد مقایسه قرار گرفته است. نتایج تحلیل­های پایداری غیر خطی هندسی و غیر خطی مصالح مدل­ها، نشان می­دهند که در ارتباط با تأثیر اعمال مد ناکاملی اولیه به مدل­ها، مدهای کمانشی را می­توان به دو گروه مدهای حساس و مدهای غیر حساس طبقه­بندی نمود. به طور کلی مدهای پایین تحلیل کمانشی، تأثیر کمی در کاهش بار حدی سازه­های فضاکار فرم آزاد دو گنبدی دارند. همچنین جهت اعمال ناکاملی اولیه هندسی در فرم­های آزاد دو گنبدی، می­توان از روش مد ناکاملی انطباق­پذیر تعمیم یافته، به عنوان یک روش مناسب استفاده نمود. در این مقاله، تأثیر برخی پارامترهای هندسی در رفتار پایداری فرم­های آزاد دو گنبدی نیز مورد بررسی قرار گرفته است.

کلیدواژه‌ها


عنوان مقاله [English]

Double Domes Free Form Space Structures: Stability Behavior and Imperfection Sensitivity Analysis

نویسندگان [English]

  • Seyed Mehdi Abbasi Mousavi
  • Karim Abedi
  • Mohamad-Reza Chenaghlou
Faculty of Civil Engineering, Sahand University of Technology
چکیده [English]

Free forms are usually used to refer double curve surfaces which are independent from groups of geometrically or mechanically constrained forms. Geometrically constrained forms are only conditioned by a geometrical definition, like it could be done on basis of simple surfaces. When there is a close relationship between forms and forces, the forms are mechanically constrained [1]. In the present study, behavior of double domes free form single layer space structures as a group of free form structures are investigated. Gaussian curvature of double domes can be positive and negative, unlike regular domes. In single layer reticulated space structures, local instability with nodal snap-through phenomenon could result in propagation in whole structure [2], so stability behavior of double domes free form single layer space structures should be investigated. The parametric study is performed in order to evaluate the effects of different variables on the stability behavior of double domes free form space structures.  

کلیدواژه‌ها [English]

  • Space structure
  • Free form
  • Double domes
  • Stability analysis
  • generalized conformable imperfection mode method
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