Connections play a crucial role in structures, including steel structures, and have a significant impact on the seismic behavior of the structure. One particular type of connection commonly used in steel structures is the Reduced Beam Section (RBS). This connection reduces the moment strength of the beam near the column, which in turn results in less moment being transferred to the column at the final moment. The study involved 30 numerical analyses conducted using ABAQUS to examine two cases. The first case involved investigating a connection with a beam that had a hole in the flange area. The variables examined included the area of the flange holes and the axial force of the column. In the second case, a yield Ring was utilized in the flange area of the beam. The radius of the yield Ring was considered as a variable insix different cases. Equations for calculating the maximum strength moment and analyzing the linear region of a beam were presented in the study. The yielding damper must yield earlier than other members, and an equation was provided to ensure that it does. Finally, the cyclic behavior of the two models was also compared. Numerical analysis revealed that if the area of the flange holes is half that of the beam flanges, the beam's strength does not significantly decrease withincreasing axial force. The elastic stiffness and ductility of the SRD-equipped connection were higher than the RBS model, with the SRD model achieving 1.8 and 2.6 times greater ductility and elastic stiffness, respectively, in the most optimal state.

Using fixed point methods, we prove the stability of orthogonally Ring homomorphism and orthogonally Ring derivation in Banach algebras.

In this study, to improve the efficiency of TLD, a Variably Baffled Tuned Liquid damper (VBTLD) was used. The baffles are so that they divide the tank into three equal parts when they are fully closed. Furthermore, when they are open or partially closed, they can serve as some obstacles and improve the energy dissipation parameters. When this damper meets an excitation with a specific frequency, the baffles can be tuned to make the frequency of sloshing equal to that frequency. VBTLD used in this paper could be set for frequency range from 1. 73 to 3 times of a specific frequency. Compared to a simple TLD, VBTLD can be tuned to a range of frequencies and improve the performance of structure against external excitation. At first, the benchmark building was modeled in OpenSees, then the performance of the device was verified by previous test results. To examine performance of VBTLD, Tuned Mass damper (TMD) with optimal parameters was used in this study. Results show that when the baffles are at the best angle, VBTLD with water depths of 42 mm has maximum response reduction for the numerical model subjected to the Kobe earthquake at intensities of 2, 4, 6 and 8% of the Initial maximum acceleration of the earthquake (PGA=0. 87g). The improvement of structural behavior compared to the optimal mass damper at maximum acceleration are respectively 23. 1, 22, 14. 6 and 10. 5% while for damper with water depths of 63 mm, they are respectively 8. 2, 9. 5, 6. 7 and 6. 8%.

Many existing buildings are irregular in plan or elevation because of asymmetric placement of masonry infills. The stiffness of masonry infill is a considerable value relating to that of the structure. Produced torsion from eccentricity because of infill stiffness leads to extra forces and deformations in structural members and diaphragms. An appropriate alternative to solve this problem especially in existing buildings is using dampers. dampers can enhance structural performance by reducing seismically induced lateral displacements and by reducing inelastic behavior of beams and columns. In this paper some simple models are used to show structural modeling and a conceptual discussion is presented on the numerical results. An accurate model for masonry infill has been used in structural model. Numerical results show the efficiency and high performance of added dampers to reduce the torsion effects in the structural elements.

In some aerospace vehicles, the tracking sensors which act in a tracking loop as stabilizer are mounted on a two degree of freedom gyro. The gyro must align its rotor axis with the line of sight in order to remove tracking errors. The tracking precision and sensitivity are functions of the gyros performance. One of the main factors in reducing the precision and producing instabilities is nutation vibration. This fluctuating motion, which is a dynamical inherent property of the system, is related to the gyro lateral moment of inertia, the length of gyro and its rotating speed. In order to investigate the capabilities of nutation damper and removing the wobble motion of a freely processing body, this paper analyzes a Ring damper partially filled with viscous liquid with taking into account the behavior of the damper and its subsystems. The equations of motion for the dynamical motion of gyro, are obtained using Lagrangian approach, taking into account the friction of dampers and interaction of the liquid with the system equations of motion.

Due to several reasons as the low resistance of constructed concrete and also change in codes or application of structures, some concrete frames need to be retrofitted. By adding the steel prop and curb to the reinforced concrete, many parameters are changed such as ductility, resistance, and stiffness. This study investigates numerically the impact of adding the prop and curb, slit damper, gusset plate and also prop with a ductile Ring on stiffness, resistance, energy dissipation and ductility of RC frames. For this purpose, the effect of the aforementioned methods on the linear and nonlinear moment frame behavior of reinforced concrete under monotonic loads have been numerically investigated using the ABAQUS software. In the present study 12 samples of reinforced frames with one story and one span retrofitted by different methods. The novelty of the paper was using such props and slit damper in RC frames. The results obtained from the modeling showed the retrofitted frame with a Ring, slit damper and gusset plate also showed a better behavior in terms of resistance and stiffness compared to the RC frame and the sample with slit damper and prop with a ductile Ring as well as compared to the sample with the prop and curb showed more ductility and energy dissipation.

One of the most common defects in rotary equipments is cracks. Creation and growth ofcracks can cause irreparable damages as well as occurrence of unwanted vibration in rotatingequipments. On the other hand, increasing the damping of the system is one of the mostpractical solutions to control vibrations in rotating equipment. One of the most importantmethods to increase the damping is the use of squeeze film dampers. Despite the highefficiency of these elements in controlling the amplitude and damping of system vibrations, their nonlinear behavior has created many limitations in the use of this equipment. In this paper, the bifurcation analysis of a flexible rotor with a floating-Ring squeeze filmdamper with centralizing spRing and consideRing the occurrence of cavitation in the damper oilfilm and transverse cracks in the shaft is been investigated.