بررسی مقایسه ای رفتار سیستم‌های سازه ای 3d پانل در حالت جعبه‌ای با و بدون بازشو

سیستم ساندویچی به دلیل سبک بودن، مقاومت بالا و عملکرد سازه‌ای و تاسیساتی مناسب به عنوان دیوارهای باربر و غیر باربر ساختمانی استفاده می‌گردند. برای انجام این تحقیق و بررسی روی نمونه‌های پانلی از نرم افزار المان‌محدود استفاده گردید. این تحقیق بر اساس مقایسه بین رفتارهای اجزای سازه پیش ساخته ساندویچی و به طور خاص دیوار پانلی در حالت مستقل و غیرمستقل با بازشو صورت گرفت. در انجام تحقیق، مدل های مورد نظر که دارای ابعاد بزرگتر با مقیاس واقعی بودند مدل شدند که از آن جمله دیوار پانلی 320 در320 سانتیمتر با بازشو و مدل های جعبه ای با و بدون سقف بودند. در مجموع شش مدل ارائه شده است. مدل دیوار مجزا به منظور بررسی رفتارهای حالت مستقل اجزاء پانلی مورد آنالیز قرار گرفت و مدل های دیگر برای تعیین اثر سیستم بر رفتار دیوار تحلیل و بررسی شدند. مواردی که در این تحقیق مورد بررسی قرار گرفتند شامل منحنی ظرفیت، ظرفیت بارپذیری، تغییر مکان، شکل پذیری و میزان جذب انرژی دیوار در مدلهای مختلف بودند، همچنین ضریب رفتار در همه مدل ها محاسبه و با هم مقایسه شدند. نوع و مکان ترک‌ها و روند گسترش خرابی و مکانیزم شکست نمونه‌ها مورد بررسی قرار گرفت. برای لحاظ نمودن اثر سیستم پانل ساندویچی، باید تاثیر المان‌های دیگر متصل شونده بر آن نیز دیده شود تا رفتار واقعی و مطلوب‌تری از آن حاصل شود.

Comparative study of 3D panel structural systems’ behavior in the box mode with and without opening

Due to lightweight, high resistance, structural performance, and appropriate installation, sandwich system is used as structural loadbearing and nonloadbearing walls. To conduct this study and investigate on panel samples, finite element software was used. This research was conducted based a behavioral comparison between sandwich prefabricated structural components, particularly panel wall, in independent and dependent mode with opening. In doing this research, the considered models that had large sizes with real scale were modeled including 320 320 with opening and box models with and without roof.Totally, 6 models have been proposed.Separate wall model was analyzed to investigate the behavior of the independent mode of panel components and other models were analyzed and studies to determine the effect on system on wall behavior. Cases that were investigated included capacity of curve, chargeability capacity, displacement, plasticity and energy absorption of wall in various models, and behavior coefficient was calculated and compared in all models. Type and location fractures and the failure propagation procedure, and failure mechanism of samples were investigated. To consider the sandwich panel system, the impact of other elements connecting to it must be ignored so that actual and optimal behavior of it to be obtained. With regard to appropriate structural and installations performance of sandwich panel systems, these walls are used load bearing and nonload bearing walls. Due to the lack of engineering parameters at the time of introduction of this system, the need for accurate and complete understanding of the structural behavior of the system is essential. In Figure 1, the details of forming the sandwich panel is shown. These panels consist of wire in sizes of 2.5 to 3.5 made of various steels and coppers (this is located at the exteror surface as steel grid known as mesh), an insulated enriched expanded polystyrene layer, polystyrene foam with thickness of mesh plates, with wired vaults. The connection of these vaults is the same type of panel grid, so that these three layers are interconnected by lateral wires. In the panel pilot project in Shanghai, China in 1997 that was one of the key projects conducted in Shanghai, sandwich panels was investigated by Zhang and Shi. In this study, a sixfloor building was examined that tested basic accelerations were limited to 0.65g (Shi Weixing, and Zhang Lixin. 1997). Regarding shotcrete concrete used in great and leader sandwich panel, they conducted some studies (Kabir, M. Z., Rezaifar, O. and Rahbar, M. R. 2005). The final resistance of the system under axial load was studied by Benayoun in 2005 (Benayoune, A., Aziz, A., Samad, A., Trikha, D. N., Abang, Ali, A. A. and Ashrabov, A. A 2005). Gara et al (Fabrizio Gara, Laura Ragni, Davide Roia, Luigino Dezi 2012) studied the bending tests on the roof of the sandwich panel. In this experiment, the effect of polystyrene foam and ending beams in tolerating the bending loads was very important. Mashal et al studied the behavior coefficient and plasticity of structure made of sandwich panels of a class (M. Mashal, A. Filiatrault 2012). In a numerical study in 2004 conducted by Kabir and Rezaei Far, dynamic parameters of system were evaluated by analyzing finite elements in nonlinear area (Kabir, M. Z. and Rahbar, M. R. 2005), followed by general behavior of shear and bending of system proposed by the Great (Kabir, M. Z. 2005). Holmberg and Pelm also analyzed the bending behavior of the system (Holmberg, A. and Pelm, E. 1986). Report of committee of prefabricated concrete panels provides comprehensive view of the system along with design example (PCI Committee on Precast Concrete Sandwich Wall Panels 1997). According to what was said, this issue is essential in determining the correct behavior of this type of system that most of parametric studies are done in this regard. In this study, the parameters affecting the behavior of sandwich panels system and determining the behavior coefficient and plasticity will be discussed.