معرفي ميراگر جديد بيضوي شكل به منظور استهلاك انرژي در سازه ها

Introduction of a new elliptical damper for seismic energy dissipation of civil structures

در پژوهش حاضر، يك ميراگر جديد بيضوي‌شكل به منظور استهلاك انرژي و كنترل خسارت در اعضاء اصلي سازه‌ها معرفي شده است، كه از يك قسمت اصلي حلقه‌ي بيضوي تشكيل شده است، كه از طريق تغييرشكل برشي انرژي را جذب مي‌كند. به منظور بررسي رفتار ميراگر پيشنهادي، نمونه‌يي از آن در آزمايشگاه آزمون شده است. آزمايش بارگذاري چرخه‌يي شبه‌استاتيكي به منظور ارزيابي ظرفيت جذب انرژي، عملكرد چرخه‌يي و رفتار ميراگر صورت گرفته است. براي اعمال نيرو در دو جهت متفاوت از دو جك هيدروليكي، براي اندازه‌گيري نيرو از دو بارسنج و براي اندازه‌گيري جابه‌جايي از جابه‌جايي‌سنج استفاده شده است. نتايج نشان مي‌دهند كه ميراگر پيشنهادي، حلقه‌هاي هيسترزيس پايدار و جذب انرژي مناسبي دارد. تأثير قطر بزرگ، نسبت قطر بزرگ به قطر كوچك، نسبت ضخامت و ارتفاع ناحيه‌ي اتصال به قطر بزرگ از طريق انجام تحليل پارامتريك مدل اجزاء محدود ميراگر و با در نظر گرفتن رفتار غيرخطي، جابه‌جايي بزرگ و خرابي مصالح انجام و مشاهده شده است.

In this paper, a new energy dissipative device named elliptical damper was introduced for passive control of structures. In the proposed damper, the energy dissipation capacity is provided by the shear deformation of the elliptical ring. To investigate the behavior of the proposed damper, a sample of this damper was tested experimentally. The results showed that the proposed damper had stable hysteresis loops and good energy absorption. Also, the finite element model was developed by considering nonlinear behavior, large deformation, and material damage. The results of the numerical model were verified through experimental results. The results showed that the numerical analysis could predict the cyclic response and damage location of the experimental sample. A parametric study was performed to investigate the changes in the cyclic behavior of the elliptical damper with its dimensions. Four independent parameters considered for this study are the greater diameter of the elliptical ring, the ratio of its diameters, the ratio of the thickness of the elliptical ring to its greater diameter, and the ratio of the height of the connection area to the greater diameter of the elliptical ring. Among the studied parameters, the thickness of the elliptical ring had the greatest effects, and the height of the connection area had the smallest effects on the cyclic response of the proposed damper. By increasing the thickness of the damper, the maximum strength and energy dissipation capacity increase, but its ductility decreases. The proposed damper has stable hysteresis loops, excellent ductility, and high energy dissipation capacity. The elliptical damper is simple in terms of construction technology and provides excellent energy dissipation capacity for the structure compared to the cost spent for its construction. According to the results, the proposed damper can be used as an appropriate energy dissipation device for passive control of structures.