كليدواژه :
مهاربند كمانش‌تاب , عضو لوله در لوله , بارگذاري چرخه‌يي , تحليل اجزاء محدود
چكيده فارسي :
در نوشتار حاضر، مطالعات پيشين در زمينه‌ي سيستم مهاربندي كمانش‌تاب تمام فولادي معرفي شده توسط نويسندگان از طريق روش‌هاي نظري و آزمايشگاهي
گسترش يافته است. سيستم پيشنهادي شامل دو عضو لوله‌يي به صورت تودرتو بوده است، كه در آن لوله‌ي داخلي به عنوان عضو تسليم‌شونده تحت بار محوري و لوله‌ي خارجي با جزئيات و ملحقات لازم به عنوان مكانيسم مقيدكننده در برابر كمانش عمل مي‌كند. در پژوهش حاضر، ضمن معرفي جزئيات سيستم مهاري پيشنهادي، رفتار آن تحت اثر بارگذاري چرخه‌يي به صورت تفصيلي مطالعه شده است. علاوه بر گزارش مطالعات آزمايشگاهي انجام شده به منظور اثبات مفاهيم مطروحه، مدل سازي‌هاي عددي مشتمل بر مدل‌سازي تفصيلي و تحليل غيرخطي با در نظر گرفتن آثار رفتار غيرخطي هندسي و مصالح و همچنين تماس انجام پذيرفته است. نتايج حاصل از مطالعات حاضر نشان از عملكرد مناسب عضو پيشنهادي به عنوان مهاربند كمانش‌تاب با رفتار متقارن و پايدار تحت بارگذاري چرخه‌يي دارد. از جمله مزاياي سيستم پيشنهادي، مي‌توان به سهولت ساخت و نصب، كاهش وزن و ميزان مصالح مصرفي، تسريع عمليات اجرايي و آثار زيست‌محيطي مطلوب اشاره كرد.
چكيده لاتين :
In this article, a new type of all-steel buckling brace is introduced. The proposed bracing member consists of two tubular members. The inner tube is intended to act as the structural core such that energy can be suitably dissipated by its yielding under cyclic loading. The outer tube is supposed to act as a lateral restraint for the inner one without interfering in the axial load-carrying inner tube, that is, using a gap separating the two tubes, the inner tube should be free to slide inside the outer one under the application of cyclic loading. Hence, axial loads are resisted by the inner core tube and the outer tube may only interfere in axial force resistance through friction at contact points after the core deforms laterally. In this study, while accurately introducing the proposed system, its behavior under cyclic loading has been studied using both experimental tests and numerical modeling. The test specimen was designed based on the parametric study previously done by the authors. In order to investigate the cyclic performance of the proposed BRB member, the displacement loading protocol proposed by the AISC was applied. Numerical modeling was performed using ABAQUS software, taking into account all nonlinear effects, including nonlinear behavior of materials, geometric nonlinearity, and contact. Based on the experimental and numerical results, it was demonstrated that the proposed BRB - if well designed - would be quite competent in accomplishing the intended tasks as a buckling restrained bracing member. Properly designed TiTBRBs can exhibit stable cyclic behavior and satisfactory cumulative plastic ductility capacity so that they can serve as effective hysteretic dampers. At the same time, such all-steel TiTBRBs concreting was eliminated; hence, much lighter members were obtained. This is also associated with ease and speed of fabrication, erection, inspection, replacement, and a more economical and environmentally friendly design.
