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Behavior of stiffened and unstiffened steel plate shear walls considering joint properties Hong-Chao Guo a,b,n , Ji-Ping Hao c , Yun-He Liu a,b a State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi′an University of Technology, No.5 Jinhua Road, Xi′an 710048, PR China b Department of Civil Engineering and Architecture, Xi′an University of Technology, No.5 Jinhua Road, Xi′an 710048, PR China c Department of Civil Engineering, Xi′an University of Architecture and Technology, No.13 Yanta Road, Xi′an 710055, PR China article info Article history: Received 23 April 2015 Received in revised form 24 August 2015 Accepted 7 September 2015 Keywords: Shear wall Stiffener Semi-rigid Energy dissipation Spring element abstract Steel plate shear wall (SPSW) systems have dual characteristics, the frame and infill wall action. The connection flexibility of frame joint not only changes the force and moment distribution, but also increases the lateral displacement and weakens the overall stability in SPSW structure. This paper presents the influence of hinged, rigid and semi-rigid connection joints on the behavior of SPSW structures. The bearing capacity, energy dissipation mechanism, failure mode, stress and deformation development process of the semi-rigid composite frame with steel plate shear walls under different stiffener forms were studied using experimental tests and finite element analysis. It was observed that with stiffeners the specimen yield load increased about 20% on the elastic stage, the ultimate bearing capacity of the diagonal stiffener was about 5% larger than the cross stiffener on the plastic stage, but the overall failure modes were basically the same. Additionally, the quantitative indications of the effect of joint stiffness on load carrying capacity were presented Thin-Walled Structures Volume 97, December 2015, Pages 53-62 guo2015.pdf

PREDICTING THE BUCKLING CAPACITY OF STEEL CYLINDRICAL SHELLS WITH RECTANGULAR STRINGERS UNDER AXIAL LOADING BY USING ARTIFICIAL NEURAL NETWORKS Z. Kalantari and M. S. Razzaghi Abstract A parametric study was carried out in order to investigate the buckling capacity of the vertically stiffened cylindrical shells. To this end ANSYS software was used. Cylindrical steel shells with different yield stresses, diameter-to-thickness ratios (D/t) and number of stiffeners were modeled and their buckling capacities were calculated by displacement control nonlinear static analysis. Radial basis function (RBF) neural networks were used to predict the buckling capacity of shells. Herein 70 percent of the results of numerical analyses were used to train the neural network and the remainders were used to test and validate the results of neural networks. Results of this study showed that RBF neural networks are useful tools to predict the buckling capacity of vertically stiffened cylindrical shells. It was also shown that buckling capacities of stiffened shells exponentially vary by distance of adjacent stiffeners (unstiffened length). Keywords Buckling, cylindrical shells, stiffener, Artificial Neural Networks چکیده به منظور بررسی ظرفیت کمانش پوسته های مطالعات پارامتریک پوسته های استوانه ای با سخت کننده های قائم، مطالعات پارامتریک به انجام رسید. برای این منظور از نرم افزار ANSYS استفاده شد. پوسته ای استوانه ای فولادی با تنش جاری شدن، نسبت ارتفاع به قطر و تعداد سخت کننده های گوناگون مدلسازی شدند و ظرفیت کمانش آنها با استفاده از تحلیل استاتیکی غیر ارتجاعی با کنترل تغییر مکان محاسبه شد. به منظور پیش بینی ظرفیت محوری کمانش از شبکه عصبی RBF استفاده شد. برای این منظور هفتاد درصد از نتایج خروجی تحلیل های عددی برای آموزش شبکه استفاده شدند و مابقی برای تست و صحت سنجی نتایج کنار گذاشته شدند. نتایج این پژوهش نشان می دهد، شبکه های عصبی RBF ابزاری مناسب برای پیش بینی ظرفیت کمانش پوسته های استوانه ای با سخت کننده قائم هستند. علاوه بر این نشان داده شد که تغییرات ظرفیت کمانش پوسته ها با فاصله سخت کننده های مجاور (طول مهار نشده) به صورت نمایی تغییر می کند. منبع دانلود 28-8-7.pdf

Numerical Analysis of Cyclic Behavior of Beam-To-Column Bolted Connections in Steel Frames Morteza Rastian; Asghar Vatani Oskouieb; Hassan Aghabaratic This article considers the seismic behavior of beam-to-column joints in steel frames for different bolt arrangements by using of finite element modeling. As the most important beam-to-column joint type, the beam-to-column joints with end-plate is chosen for the analysis. Four different specimens have been analyzed. These models had some differences such as bolt arrangement and the presence or absence of end-plate stiffeners. Design of bolts arrangement and stiffeners have been done based on the AISC standards. Two vertical bolt arrangements, with or without stiffener and two other models with horizontal bolt arrangement, with or without stiffeners have been considered. Different aspects such as energy absorption, ductility, initial stiffness and effective stiffness for all specimens have been compared. Finally effect of pre-stressing of all specimens has been assessed. As a result, comparison between vertical bolt arrangement and horizontal bolt arrangement has shown that the vertical bolt arrangement is more advantageous, especially in energy absorption منبع دانلود JSEG351427657400.pdf

Buckling of Stiffened Thin-Walled Cylindrical Shells under Axial Compression with Symmetrical Imperfections Armin A.NobakhtNamin This study aimed to investigate the effects of stiffeners on buckling of thin cylindrical shells under uniform axial compression. To this end, more than 300 finite element models of stiffened cylindrical shells were prepared. The variables considered are shell thickness, number, dimension and the location of the vertical and horizontal stiffeners as well as circular symmetrical imperfections. Results show that the stiffeners can increase buckling of the stiffened cylindrical shells under axial compression. It is also shown that buckling of the cylindrical shells is susceptible to some circular imperfection patterns. In this context, buckling graph of the models are compared with each other; obviously, the stiffened shells with more stiffeners have upper buckling graph in force - displacement curves. منبع دانلود JSEG281354307400.pdf