Investigation of performance of steel plate shear walls with partial plate-column connection (SPSW-PC)

Mojtaba Gorji Azandariani,Majid Gholhaki,Mohammad Ali Kafi,Tadeh Zirakian,Afrasyab Khan,Hamid Abdolmaleki,Hamid Shojaeifar 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.1

This research endeavor intends to use the implicit finite element method to investigate the structural response of steel shear walls with partial plate-column connection. To this end, comprehensive verification studies are initially performed by comparing the numerical predictions with several reported experimental results in order to demonstrate the reliability and accuracy of the implicit analysis method. Comparison is made between the hysteresis curves, failure modes, and base shear capacities predicted numerically using ABAQUS software and obtained/observed experimentally. Following the validation of the finite element analysis approach, the effects of partial plate-column connection on the strength and stiffness performances of steel shear wall systems with different web-plate slenderness and aspect ratios under monotonic loading are investigated through a parametric study. While removal of the connection between the web-plate and columns can be beneficial by decreasing the overall system demand on the vertical boundary members, based on the results and findings of this study such detachment can lower the stiffness and strength capacities of steel shear walls by about 25%, on average.

Eringen's nonlocal theory for non-linear bending analysis of BGF Timoshenko nanobeams

Azandariani, Mojtaba Gorji,Gholami, Mohammad,Nikzad, Akbar Techno-Press 2022 Advances in nano research Vol.12 No.1

In this paper, the non-linear static analysis of Timoshenko nanobeams consisting of bi-directional functionally graded material (BFGM) with immovable ends is investigated. The scratching in the FG nanobeam mid-plane, is the source of nonlinearity of the bending problems. The nonlocal theory is used to investigate the non-linear static deflection of nanobeam. In order to simplify the formulation, the problem formulas is derived according to the physical middle surface. The Hamilton principle is employed to determine governing partial differential equations as well as boundary conditions. Moreover, the differential quadrature method (DQM) and direct iterative method are applied to solve governing equations. Present results for non-linear static deflection were compared with previously published results in order to validate the present formulation. The impacts of the nonlocal factors, beam length and material property gradient on the non-linear static deflection of BFG nanobeams are investigated. It is observed that these parameters are vital in the value of the non-linear static deflection of the BFG nanobeam.

Proposing a dynamic stiffness method for the free vibration of bi-directional functionally-graded Timoshenko nanobeams

Mohammad Gholami,Mojtaba Gorji Azandariani,Ahmed Najat Ahmed,Hamid Abdolmaleki Techno-Press 2023 Advances in nano research Vol.14 No.2

This paper studies the free vibration behavior of bi-dimensional functionally graded (BFG) nanobeams subjected to arbitrary boundary conditions. According to Eringen's nonlocal theory and Hamilton's principle, the underlying equations of motion have been obtained for BFG nanobeams. Moreover, the variable substitution method is utilized to establish the structure's state-space differential equations, followed by forming the dynamic stiffness matrix based on state-space differential equations. In order to compute the natural frequencies, the current study utilizes the Wittrick-Williams algorithm as a solution technique. Moreover, the nonlinear vibration frequencies calculated by employing the proposed method are compared to the frequencies obtained in previous studies to evaluate the proposed method's performance. Some illustrative numerical examples are also given in order to study the impacts of the nonlocal parameters, material property gradient indices, nanobeam length, and boundary conditions on the BFG nanobeam's frequency. It is found that reducing the nonlocal parameter will usually result in increased vibration frequencies.

Micro-finite element and analytical investigations of seismic dampers with steel ring plates

Ali Mohammad Rousta,Mojtaba Gorji Azandariani 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.5

This study investigated the yielding capacity and performance of seismic dampers constructed with steel ring plates using numerical and analytical approaches. This study aims to provide an analytical relationship for estimating the yielding capacity and initial stiffness of steel ring dampers. Using plastic analysis and considering the mechanism of plastic hinge formation, a relation has been obtained for estimating the yielding capacity of steel ring dampers. Extensive parametric studies have been carried out using a nonlinear finite element method to examine the accuracy of the obtained analytical relationships. The parametric studies include investigating the influence of the length, thickness, and diameter of the ring of steel ring dampers. To this end, comprehensive verification studies are performed by comparing the numerical predictions with several reported experimental results to demonstrate the numerical method's reliability and accuracy. Comparison is made between the hysteresis curves, and failure modes predicted numerically or obtained/observed experimentally. Good agreement is observed between the numerical simulations and the analytical predictions for the yielding force and initial stiffness. The difference between the numerical models' ultimate tensile and compressive capacities was observed that average of about 22%, which stems from the performance of the ring-dampers in the tensile and compression zones. The results show that the steel ring-dampers are exhibited high energy dissipation capacity and ductility. The ductility parameters for steel ring-damper between values were 7.5 to 4.1.

Buckling analysis of smart beams based on higher order shear deformation theory and numerical method

Pouyan Talebizadehsari,Arameh Eyvazian,Mojtaba Gorji Azandariani,Trong Nhan Tran,Dipen Kumar Rajak,Roohollah Babaei Mahani 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.5

The buckling analysis of the embedded sinusoidal piezoelectric beam is evaluated using numerical method. The smart beam is subjected to external voltage in the thickness direction. Elastic medium is simulated with two parameters of spring and shear. The structure is modelled by sinusoidal shear deformation theory (SSDT) and utilizing energy method, the final governing equations are derived on the basis of piezo-elasticity theory. In order to obtaining the buckling load, the differential quadrature method (DQM) is used. The obtained results are validated with other published works. The effects of beam length and thickness, elastic medium, boundary condition and external voltage are shown on the buckling load of the structure. Numerical results show that with enhancing the beam length, the buckling load is decreased. In addition, applying negative voltage, improves the buckling load of the smart beam.

The Wall–Frame Interaction Effect in Corrugated Steel Plate Shear Walls Systems

Ehsan Vaziri,Mohammad Gholami,Mojtaba Gorji Azandariani 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5

The corrugated steel plate shear wall (CSPSW) system is a lateral force-resisting system, about which many studies have been carried out in recent years. In the present study, the behavior of this system is investigated by pushover analysis. For this purpose, twenty CSPSWs structures are designed with width-to-height ratio (L/H) of 2.5, 2, 1.4, and 0.85, and the number of fl oors 1, 2, 4, 6, and 10 were designed and analyzed using the ABAQUS fi nite element software package. The results of this study show that the initial stiff ness of CSPSWs is high and reaches its ultimate capacity at a thrust ratio of 0.1%; on the other hand, after the buckling in the infi ll plate, the stiff ness and base shear of the plate shear wall (PSW) signifi cantly decreases. Also, the results show that the infi ll plate tolerates a higher percentage of shear force before the buckling of the plate, but after buckling, the frame tolerates a higher percentage of the shear force. In multi-story structures, the boundary frame with shear performance in the lower fl oors has a more eff ective role in bearing shear force. Moreover, in the present study, an equation is presented for calculating the tension fi eld inclination angle. According to the equation, the tension fi eld inclination angle depends only on the PSW aspect ratio. Finally, a method is presented for estimating the uniform force–displacement curve of the single- and multi-story CSPSW systems. This method is obtained based on the corrugated plate-frame interaction (PFI) and was confi rmed with the force–displacement curve of experimental specimens and numerical models.

Steel dual-ring dampers: Micro-finite element modelling and validation of cyclic behavior

Mahdi Usefvand,Ali Mohammad Rousta,Mojtaba Gorji Azandariani,Hamid Abdolmaleki 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.4

Extensive studies have been performed by researchers to increase the ductility and energy-absorption of concentrically braced frames. One of the most widely used strategies for increasing ductility and energy-absorbing is the utilization of energy-dissipation systems. In this regard, the energy-dissipation system consisting of a steel dual-ring damper (SDRD) with different construction details is presented, to improve hysteresis behavior and performance of steel ring dampers (SRD). The most important cause of energy-dissipation in SRDs are the development of bending plastic hinges in the rings. Therefore, by adding an inner ring to the SDR system, it increases the number of moment plastic hinges and in turn increases energy dissipation. Parametric studies havse been performed applying the nonlinear micro-finite element (MFE) procedure to investigate the improved models. The parametric studies comprise examining the efficacy of thickness parameters and the inner ring diameters of the improved models. The SRD models was selected as the base model for comparing and evaluating the effects of improved dampers. MFE models were then analyzed under cyclic loading and nonlinear static methods. Confirmation of the results of the MFE models were performed against the test results. The results indicated that the diameter to the thickness ratio of inner ring of SDRDs has a considerable influence on determining the hysteresis behavior, ductility, ultimate capacity and performance, as well as energy dissipation. Also, the results show that the details of the construction of the internal and external ring connections were a considerable effect on the performance and hysteresis behavior of SDRDs.

Cyclic behavior of an energy dissipation semi-rigid moment steel frames (SMRF) system with LYP steel curved dampers

Ali Mohammad Rousta,Hamid Shojaeifar,Mojtaba Gorji Azandariani,Sajad Saberiun,Hamid Abdolmaleki 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.2

The use of displacement-dependent steel curved dampers as fuse or interchangeable element in the beam-to-column connection region is one of the newest methods for improving the seismic performance of semi-rigid moment steel frames (SRMF). In the present study, performance of low-yield strength curved dampers in MRSF has been investigated. These dampers are inactive and install in the beam-to-column connection region. Variable parameters of this study involve the damper width (75, 100 and 125 mm), damper thickness (10, 15, 20, 25 and 30 mm) and the damper steel type (SN400YB and LY160). Evaluation of MRSF models were performed using finite element method by ABAQUS. For validation, a MRSF with curve dampers was modeled that had been experimentally tested and reported in previous experimental research and a good agreement was observed. The results show that the use of low-yield strength steel in curved steel dampers, depending on the damper thickness, can lead to an increase in the hysteresis equivalent damping ratio, ductility parameter and total energy dissipated compared to the steel with higher yield stress.