Concentrically braced frames, CBFs, are the common systems to provide lateral stiffness and strength in buildings that in Comparison with other systems such as moment resisting frames and eccentrically brace frames have less seismic energy dissipation and ductility. This defect caused many studies in the recent years to improve the ductility and seismic performance of them. In this paper, by making hole in the middle or end GUSSET PLATEs on diagonal and X-braces samples by doing nonlinear static analysis with ABAQUS software, it was tried to provide more ductility and to improve the seismic performance of the brace. This performance is based on the brace buckling prevention. Therefore, holes should be designed in such a way that have less axial capacity than brace critical buckling load to help earthquake energy dissipation. Hysteresis Curves show ductile behavior enhancing energy dissipation during cyclic loading of the final specimens and postponing the occurrence of buckling in the brace members until displacement about 2 cm while normal braces buckled in 1 cm displacement. The reduction of frame stiffness approximately 8-57% and 12-17% increment of equivalent damping prove more ductility and better seismic behavior of the proposed system.

1. Introduction: In this research, the hysteretic behavior of 14 inverted-V braces and their GUSSET PLATE connections subjected toinelastic cyclic loading is examined through analytical simulations. It was modeled in ABAQUS software and theanalysis type was static nonlinear analysis. GUSSET PLATEs with a constant thickness but with different sizes andshapes were used…..

The aim of this research work is to study the flexural behaviour of steel beam-column connection with GUSSET PLATE under static loading condition. Connections are normally the focal points of receiving damage due to overload including earthquake. The main reason for the failure of connection is, their inability to deliver large rotation. GUSSET PLATEs are used for connecting two or more members together. While GUSSET PLATEs are used as the connecting element of bracing to the beam-column joint, the load carrying capacity and stiffness of beam-column joints are possible to increase. To know the increasing capacity of beam-column connection with GUSSET PLATE are determined by conducting the experimental and analytical program. An experimental research demonstrates the actual behaviour of steel beam-column connection with GUSSET PLATE. There are four number of specimens are tested under static loading condition. Each specimen is fabricated by changing the connection parameter like GUSSET PLATE thickness, angle leg length. Finite element analysis was done using ABAQUS. Using the finite element model, a parametric study was conducted to determine the changes in the connection and initiation of damages. The contact element which is used as a surface to surface instead of node to node. Accurate results can be obtained by validating the results of experimental work with FEM analysis. The comparison is made for the deflection and strain occurred on the experimental program with the analytical results.

Concentrically braced frames, CBFs, are among common lateral load carrying systems and their relative advantages, such as ease of implementation and lower cost compared to moment resisting frames, has led to their widespread usage. Experiences of past earthquakes indicate that the inherent defects and brittle behavior due to the buckling of compressive braces are the cause of the main damage in structures. In this paper, by making a hole in the GUSSET PLATEs of diagonal bracing samples, it was endeavored to provide more ductility and improve the seismic performance of CBF through nonlinear static and dynamic analyses using ABAQUS software. For this purpose, holes were designed to have less axial capacity than the brace critical buckling load to help earthquake energy dissipation. The effects of hole shape and dimension and, also, the effect of near and far field earthquakes, were studied. Concentration of inelastic response in the hole neighborhood, results in high energy dissipation and prevents nonlinear behavior in other elements. The hysteresis curves show ductile behavior, enhancing energy dissipation during cyclic loading of the final specimens and postponing the occurrence of buckling in the brace members until lateral displacement at about 2cm. Normal braces buckle in 1cm displacement, leading to brittle behavior. The increase of the frame final displacement between 13-43% and base shear reduction between 19-37% demonstrate the superior seismic behavior of the proposed system. Moreover, equivalent damping ratios in the proposed samples are significant by about 20% The proposed model is relatively easy to implement in a variety of braces, such as X-braces, chevron and diagonal con gurations, without too much cost. In this research, by a slight change in the common system and without using complicated devices, energy dissipation is provided. This is one of its distinctive features compared to other research projects.It should be noted that due to the appropriate results obtained in numerical analysis, specimen fabrication and experimental work should be on the agenda to verify the results in the next stage of research.

IntroductionOne of the biggest problems in growing legumes like peas is harvesting these types of crops. During the machine harvesting process the harvest loss is very high. Therefore, in most parts of Iran chickpea harvested by hand and this is very tedious. Based on the literature review there are different types of harvesting machines which designed, constructed and optimized by Miller et al., 1990; Golpira, 2015; Shahbazi, 2011; Jalali and Abdi, 2014; Mahamodi, 2016. But using different varieties of chickpea in mountainous areas has limited the use of harvesting mechanisms. The purpose of this study is mechanization of the harvesting process of chickpea with low losses and suitable performance. Moreover the optimization process of lowering the weight of the header was carried out by modeling of software.Materials and MethodsTo reduce the amount of chickpea losses from the reel, a PERFORATED PLATE with defined holes was installed in the header, where the separated chickpea pods fell behind the PLATE without returning to the farm. By using the PLATE in the header of the chickpea harvesting machine and by changing the harvesting height at the three levels of 10, 15 and 20 cm and the distance of the cutter at three levels of 3, 5 and 7 mm, the performance of the machine was evaluated. The experiments were carried out with Caboli variety cultivated in Kurdistan province, which is proper for mountainous areas without regular watering condition in three replications. The plants were placed in a fiber, wooden PLATE considering farm conditions. In addition, the header was modeled statically and dynamically under the influence of the external forces applied to the header using Ansys and Abaqus software. Based on the actual data, the validity of the applied model was determined and according to the verification results the optimization of the header was performed considering minimal weight (to reduce energy consumption).Results and DiscussionThe evaluation results of the performance of header showed that the effects of using PERFORATED PLATE and the height of the header for harvesting on the chickpea harvesting and losses are significant at the level of 1% and 5%, respectively, and the interaction between PERFORATED PLATE and the header height on the chickpea loss is significant at 5%. Using a PERFORATED PLATE in the harvesting machine increases the amounts of chickpea collected from the farm increases. In this condition the chickpea pods separated from the plant and passed through the PLATE. With the separation of the stems, due to the proper wear that exists between the PLATE and the reel, the pods are properly separated and pass through the PERFORATED PLATE. Moreover, the chickpea loss is higher for the system without PERFORATED PLATE. The effect of the distance between the reel and header PLATE is affects the remaining chickpea on the PLATE. By increasing the distance from 5 mm to 7 mm the amount of harvested had a considerable effect. The best method of harvesting chickpeas is at the kinematic index of 1.5 with PERFORATED PLATE, the harvesting height of 15 cm and the distance of 5 mm. According to modeling processes of the reel and the results of the static analysis, the minimum and maximum stress values were recorded about 3.31 MPa and 6.50 MPa (based on the von misses criteria), respectively, which is very small compared to the yield stress of the reel constructed with St-37. Also, the results of the dynamic analysis of the reel showed that the maximum von misses stress occurred with increasing the kinematic index. The maximum stress for kinematic index of 1, 1.5 and 2 was observed about 32.2, 40.1 and 52.72 MPa, respectively. The results of 3D model validation showed that the applied model with Abaqus software (R2>0.9264) was able to predict the amount of stress in different parts of the reel.ConclusionIn this study, the changes were made on the chickpea harvesting machine to get the proper performance and increasing machine efficiency. A PERFORATED PLATE was used to prevent pea’s losses. The best condition for the harvesting process is obtained with the harvesting height of 15 cm and the distance of 5 mm. By using 3D modeling of the reel weight was reduced about 10%.

Convergent braces are usually used for stability of frames against lateral forces in seismic design. According to the seismic design philosophy, it's expected that convergent bracing systems could show a non-elastic and steady response under intense earthquakes. In such frames, braces are connected to beams and columns by a PLATE and non-elastic deformation occurs at the time of yield of the member by tensile and non-elastic buckling. The new experimental tests show that the seismic performance of convergent braces improves by connection PLATE design and permitting connection PLATE to yielding.In this research, the connection PLATE effects and its changes and also the inelastic finite element model and analysis methods are investigated and compared with experimental results. Important details in frames connection are including the effect of brace PLATE in rigidity of the column-beam connection, shape and thickness of connection PLATE and analysis of non-elastic deformations. The proposed results will lead to improve the shape and details of this type of connections.

In this paper, topology optimization (TO) is applied to determine the form, size and location of holes for the special form of PERFORATED steel PLATE shear wall (PSPSW). The proposed model is based on the recently presented particular form of PSPSW that is called the ringshaped steel PLATE shear wall. The strain energy is selected as the objective function in the optimization. Simple Isotropic Material with Penalization (SIMP) method and the solution algorithms, including sensitivity and condition-based methods are utilized in the TO. Four initial PLATE forms are presented in the TO with regards to the length of the connection between the PLATE and column. Based on the solution methods and initial forms of the PLATE, eight scenarios are proposed and seven different PERFORATED PLATEs obtained using TO. The nonlinear responses of the optimized PERFORATED PLATEs are compared together, and with the ring-shaped model as a benchmark. The nonlinear analysis is conducted under cyclic and monotonic loadings. Key issues include cyclic and monotonic behavior, pinching behavior, stiffness, load-carrying capacity, energy dissipation, fracture tendency and out-of-plane deformation are investigated and discussed. The results demonstrate the optimized models have better behavior than the ring-shaped model without changing the volume of the PLATE.

Thin PERFORATED Steel PLATE Shear (SPS) Walls are among the most common types of energy dissipating systems. The applied holes reduce the shear strength of the PLATE and allow to decrease the profile size of the members at the boundary of the panel when these systems are used in the typical design of structures. On the other hand, the different fracture locations of these panels are visible when considering the different perforation patterns. This paper reports on the results obtained from the experimental study under cyclic loading of the effect of different hole patterns on the seismic response of the systems and the location of the fracture. According to this, two PERFORATED specimens by different patterns were considered. In addition, a PLATE without holes for a better comparison of the fracture location was chosen. The results showed that changing the pattern of the holes causes a change in the fracture location. Moreover, in PERFORATED specimens, the amount of shear strength did not reduce suddenly after the fracture phenomenon. In the specimen which was PERFORATED around the web PLATE, the pinching force was more than any other in the low cycle of the drifts. For this reason, the energy dissipation and initial stiffness were more than up to 3% drift. The experimental specimens were then simulated with a Finite Element (FE) method using the ABAQUS. Finally, a parametric FE analysis on different series of PERFORATED panels, by changing the diameter of the holes and the PLATE thickness, has been carried out.

Concrete-filled steel tubular (CFST) GUSSET PLATE connection is a commonly used method in which the PLATEs are welded directly to the columns. Due to the importance of stress distribution and energy absorption capacity on the behavior of the mentioned connections, in the present study, numerical analysis of the behavior of these connections under different loadings has been investigated. The studied variables include the thickness of the GUSSET PLATE, the compressive strength of the concrete, the D/t (diameter to thickness) ratio of CFST, and the type of loading. The results show that although filling hollow tubular sections with concrete prevents the local buckling of the steel wall, the use of concrete with higher compressive strength does not always lead to increased load capacity and energy absorption, so in many of the studied models, the energy absorption capacity decreases by 18% to 30%. On the other hand, the results showed that the diameter-to-thickness ratio has a significant effect on the energy absorption capacity of the simulated connections so by increasing this ratio, the energy absorption capacity has decreased in the range of 76% to 91%. Also, the loading condition is effective in the load-bearing capacity and the energy absorption of the structure. So that in the case of eccentric tension and in-plane bending, the energy absorption capacity is reduced by 53% and 86%, respectively, compared to axial tension loading.