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Vertical static loading tests were carried out on two kinds of continuous span concrete composite slabs with beam and slab connected by studs and open-hole folding plate connectors. Combined with the test results, on the basis of the analysis of load–deflection curves and load-reinforcement strain curves, the finite element software ABAQUS was used for the numerical study of the continuous span concrete composite slabs. The plate thickness, concrete strength, thickness of the shear key and slab span has carried on the finite element analysis. The results show that the strength of the concrete and the thickness of the shear bond have little effect on the flexural performance of the continuous span concrete composite slab, but the shear bond can strengthen the connection between the slab and the steel beam and reduce the sliding and lifting of the composite slab on the steel beam. The slab thickness and slab span have a great influence on the flexural performance of continuous span concrete composite slabs. The peak load of the specimen increases with the increase of slab thickness and decreases with the increase of slab span. This study will provide a theoretical basis for future design and engineering application of composite slabs.

Historical buildings are distinct structures in terms of seismic performance and extensive evaluations focusing on their seismic mechanisms and responses have yet to be clarified and presented. Thus, it was aimed to present a methodology consisting of various analysis approaches for historical buildings to increase the seismic strength. This study also covers rehabilitation applications for a historical masonry structure that was originally designed as the hospital building, however, later refunctioned to serve as the military prison, and presently in use as a university building. The pre-defined tasks in the study are implemented in three stages. Firstly, the material properties of building components were determined through field study and laboratory tests. Secondly, a series of simulations such as linear, non-linear, and kinematic analyses were performed using finite element software. As a result of the analysis, it was determined that the structure did not satisfy the targeted performance levels, as well as vertical and lateral bending mechanisms emerged. Therefore, a rehabilitation stage is presented due to the unsatisfactory seismic strength of the building. This work examines the seismic performance and proposes a rehabilitation approach for masonry buildings focusing on a particular and significant case, which includes the first structure built using solid bricks in Istanbul in the Ottoman era.

As an important connection method between drill pipes, the thread is prone to fatigue cracks and stress corrosion cracks due to long-term exposure to complex forces and corrosive environments. The thread crack detection system of drill pipe based on altering current field measurement (ACFM) is proposed. The crack detection model of the drill pipe thread using ACFM is developed by the finite element software COMSOL. The distribution of the induced magnetic field above the thread is extracted. The relationships between the characteristic signal and the depth and angle of the crack are analyzed. The drill pipe thread detection probes and the detection system are established, and different types of cracks on two different specifications of threads are detected. The experimental results show that the detection system can achieve full coverage detection of the thread crest and root, and cracks at different angle can be identified effectively on the thread.

In this paper, a new form of structural design of the combination column—Cellular U-shaped steel combination column, as vertical force components applied to steel structure buildings. By changing the diameter size of honeycomb holes, the thickness of U-shaped steel and embellished plates, and the steel strength, the seismic properties of this new combination steel column are studied by using ABAQUS finite element software. Results the setting of honeycomb hole is reduced by part, the delay of the test piece and its energy consumption capacity are improved to varying degrees, the stiffness degradation rate is improved, and the setting of honeycomb steel plays a certain role in the seismic performance of the steel column. The experiment is used as a reference, and the destruction form and carrying capacity are compared, so that the numerical model has some credibility. Results the strength and stiffness of the cell U-shaped steel grid composition column are analyzed to meet the standards, the seismic performance is good, and can be applied to engineering practice.

PurposeSigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible to local, distortional and lateral-torsional buckling, as possible failure modes when compared to common I-sections and hollow cross-sections. However, the instability phenomena associated to these members are not completely understood in fire situation. Therefore, the purpose of this study is to analyse the behaviour of beams composed of cold-formed sigma sections at elevated temperatures.Design/methodology/approachThis study presents a numerical analysis, using advanced methods by applying the finite element software SAFIR. A numerical analysis of the behaviour of simply supported cold-formed sigma beams in the case of fire is presented considering different cross-section slenderness values, elevated temperatures, steel grades and bending moment diagrams. Comparisons are made between the obtained numerically ultimate bending capacities and the design bending resistances from Eurocode 3 Part 1–2 rules and its respective French National Annex (FN Annex).FindingsThe current design expressions revealed to be over conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the general prescriptions, the first having a better agreement with the numerical results.Originality/valueFollowing the previous comparisons, new fire design formulae are analysed. This new methodology, which introduces minimum changes in the existing formulae, provides at the same time safety and accuracy when compared to the numerical results, considering the occurrence of local, distortional and lateral-torsional buckling phenomena in these members at elevated temperatures.

The accuracy of the prediction and reliability of the deflection basin area index method for rigid pavement heavily depend on the sensor layout scheme and the calculation theory. A total of 154 groups of deflection data were generated by the finite element software in different conditions, and the simulated results were in good agreement with the analytical solutions of thin plates on elastic foundation. The accuracy of several types of deflection basin area index methods was assessed with the database of pavement deflection results. It is found that, apart from densifying the distal sensor layouts locally, replacing the deflection value of a specific point with the average of all measured points in the deflection basin area index was also an effective measure to improve the back-calculation accuracy of pavement structural parameters up to 40%. Finally, a new deflection basin area index method was proposed based on the deflection database with the regression analysis. Comparisons between the theoretical calculations of several models and the practical deflection data of an airport in northern China revealed that the newly proposed method performs better on the back-calculation accuracy and efficiency, which can provide a valuable guideline for the practical engineering in the design.

This study reports on the forging simulation of P91 steel at a temperature range of 900–1200°C and a strain rate range of 1–15 s−1 using Deform 3D finite element software. The study investigated th...

Many engineers are interested in the progressive collapse phenomenon, considering multi-user typical buildings, construction bias toward economization and thus, reduction of material consumption. The key factor in progressive collapse is the disproportion between the initial and final damage which sometimes can lead to the destruction of the whole building. So, the efforts are focused to prevent the expansion of initial damage through some strategies such as strengthening some load-bearing elements or choosing a proper plan. GSA and UFC regulations are two very reliable resources regarding the progressive collapse in which the alternative path method (APM) is one of the most common methods to evaluate building response to progressive collapse. In this study, the influence of typical concrete building plans (i.e. square and rectangular) on progressive collapse is investigated by 3D modeling of the buildings using LS-DYNA finite element software and removing a corner column using APM, considering GSA and UFC regulations. The results indicate that removing a corner column in the rectangular building has more intense effects including doubling the downward collapse rate, increasing the shear and axial loads in columns by 1.5 times, reciprocating motion of shear loads and higher energy absorption rate in comparison with those in the square building.

Objectives To analyze the biomechanical system of anterior retraction with clear aligner therapy (CAT) with and without an anterior mini-screw and elastics. Materials and Methods Models including a maxillary dentition (without first premolars), maxilla, periodontal ligaments (PDLs), attachments, and aligners were constructed and imported to finite element software. Three model groups were created: (1) control (CAT alone), (2) labial elastics (CAT with elastics between the anterior mini-screw and buttons on central incisors), and (3) linguoincisal elastics (CAT with elastics between the anterior mini-screw and precision cuts on the lingual sides of the aligner). Elastic forces (0–300 g, in 50 g increments) were applied. Results CAT alone caused lingual tipping and extrusion of the incisors. Labial elastics caused palatal root torquing and intrusion and mesial tipping of the central incisors, while linguoincisal elastics produced palatal root torquing and intrusion of both central and lateral incisors. Second premolars were intruded in all three groups, with less intrusion in the linguoincisal elastics group. For the control group, stress was concentrated on both labial and lingual root surfaces, alveolar ridge, and cervical and apical PDLs. Stress was more concentrated in the labial elastics group and less concentrated in the linguoincisal elastics group. Conclusions CAT produced lingual tipping and extrusion of incisors during anterior retraction. Anterior mini-screws and elastics can achieve incisor intrusion and palatal root torquing. Linguoincisal elastics are superior to labial elastics with a lower likelihood of buccal open bite. Root resorption and alveolar defects may occur in CAT, more likely for labial elastics and less likely for linguoincisal elastics.

To study the role of the effective pressure on the percolation rate of coal, the effect of gas pressure, gas adsorption, and temperature on coal is taken into consideration comprehensively. Starting from the research direction of effective pressure and porosity, the coal body percolation rate and effective pressure equations considering the influence of temperature and gas pressure are established. The experiments on the percolation characteristics of raw coal are implemented under different effective pressure by using the independently developed thermos-solid-gas linking triaxial servosystem. The theoretical equation of the effective pressure and percolation rate of coal is calculated with the finite element software COMSOL, and the results obtained from the theoretical equation agree well with the experimental results. The results show that the percolation rate of coal gradually decreases with the growth of the effective pressure when the gas pressure and temperature are kept unchanged. Therefore, the results of the research are of certain reference value for the effective prevention of gas disaster.

On April 25, 2015, a M8.1 earthquake happened near Pokhara, Nepal, and aftershocks occurred continuously which caused significant losses. In November 2015, the authors made an in-depth investigation on the earthquake damages of various engineering structures in Nepal. As the post-disaster reconstruction work has not been completed, up to this day, the current reconstruction work is still worthy of continuous attention. Firstly, the earthquake damage of typical frame and masonry buildings in Nepal was described and the causes of damage were analyzed. The reinforcement measures and suggestions were putted forward for post-earthquake reconstruction, which focused on the load transmission path of the structure, the enclosure structure, the beam-column joints, the integrity of the structure, house site selection and structural stiffness. With the help of the finite element software, the numerical modeling analysis of the wall reinforcement measures and a typical reconstruction house was carried out. The results show that the seismic performance of masonry wall can be greatly improved after being wrapped by reinforced concrete or seismic band, the use of seismic band in reconstruction of typical houses in Nepal can effectively improve the seismic performance of buildings. The surrounding areas of door and window openings are still the most vulnerable places to be damaged. Reinforcement should be strengthened in these locations.

The fiber reinforced polymer (FRP) bars are used in hollow concrete columns (HCCs) to alleviate the steel-reinforcement corrosion problem and to make an efficient and lightweight structure. The presented study has endeavored to numerically and theoretically explore the structural behavior of hollow concrete columns (HCCs) reinforced with glass fiber reinforced polymer (GFRP) bars and spirals. Six HCCs were simulated in a commercial finite element software ABAQUS 6.14. The control finite element model (FEM) was calibrated for various variables of HCCs using the previous experimental testing results. The complex nonlinear behavior of concrete was defined using the concrete damaged plastic model (CDPM) and the behavior of GFRP bars was considered as linear elastic. The proposed FEM portrayed a close correlation with the testing results of HCCs. Moreover, the different empirical models were proposed for predicting the two-peak loading behavior of FRP-reinforced HCCs based on a large database constructed from the previous research.

Dowels are connected to two masonry units in the vertical direction for the continuity and integrity of walls. According to the national and international literature, studies investigating the effectiveness of dowels on masonry walls are rare. This paper presents a preliminary experimental study performed on tuff stone masonry specimens with dowels to assess the effects of dowels on the shear capacity of masonry walls. For this aim, 54 masonry specimens, nine being controls without dowels and 45 with different dowel diameters and axial load levels, were tested under triplet test procedures, according to TS EN 1052-3 regulations. Numerical validations were performed using the LUSAS finite element software package. The experimental results were compared with numerical simulations. The present study reveals that dowels significantly improve the shear capacity of masonry walls. Furthermore, recommendations regarding suitable dowel ratios are made.

Jelen cikk a modern mérnöki gyakorlatban egyre többet alkalmazott optimalizálási technikák, azon belül is részletesebben a topológiai optimalizálási problémák kereskedelmi végeselemes szoftverekkel való megoldásával foglalkozik. Bemutatásra kerülnek az Abaqus általános célú VEM szoftveren belül az optimalizálási eljárás főbb jellemzői. Áttekintjük a modern mérnöki anyagok, mint például a kompozitok, avagy a funkcionálisan gradiens anyagok vizsgálatának lehetőségeit is egyszerű mintapéldákon keresztül.

The performance of deep excavations is governed by the ground conditions such as soil stiffness and in situ stress conditions. Cantilever secant pile wall (CPW) is one of the retaining systems which are used to support deep excavation. Its lateral deflection has great importance as it shows the behavior of CPW in the soil. Two dimensional analysis (2D) and three dimensional analysis (3D) may be used to get the lateral deflection in numerical solution. This study is focused on 2D and 3D analysis for CPW in soft clay. The finite element software "Abaqus/CAE-v6.9" has been used in the analysis. The 2D study analysis takes into account the different CPW depths and its diameter effect. The construction stages effect on the lateral deflection have been studied also. The 3D study analysis takes into account the different excavation geometry “the length and width of the excavation” effect, also different depths for CPW in 3D analysis have been studied also. The results showed that longer CPW has larger lateral deflection while CPW diameters have no effect on lateral deflection. Later deflection in one construction stage may be double that of previous stage. Also it was found that later deflection in three dimensional (3D) analysis is higher than the 2D analysis by three times. This confirms that 3D analysis of CPW in soft clay leads to more accurate results than 2D analysis.

The cold-formed steel members often require web openings to save interior space and allow for building services such as mechanical piping, electrical wiring, and air conditioning systems. Stress distribution in members with openings is different from members without holes, and therefore, their characteristics, shape, and modes of buckling are dissimilar which results in distinct behavior that could increase or decrease elastic buckling capacity and ultimate strength. In this study, analytical solutions for the local buckling of cold-formed steel webs with rectangular holes subjected to compression, bending and their combination are developed and summarized. The effects of flanges and other forces such as shear and torsion are not considered. The main variables are height of openings to height of web, aspect ratio of openings, and stress distribution gradient above or under the hole. These solutions can be used for a wide range of rectangular web openings for any sections. Analyses were conducted using energy-based methods, and the results were compared with numerical data obtained from the commercial finite element software (ABAQUS). The numerical results demonstrate that the three of the six proposed formulas can be used to predict the critical buckling stress of cold-formed steel webs with rectangular holes with regard to the aspect ratio of the web opening.

Only a seismic analysis of tunnels at a single-phase site can be performed using the commonly used finite element software owing to the lack of a dynamic two-phase element. The seismic analysis of ...

Historical masonry arch bridges are one of most important structures which transfer to cultural heritage of ancient civilizations to the present. These bridges have been one of the most important elements of transportation, trade and architecture in the past. However, nowadays, with the development of new construction materials and methods, masonry arch bridges are no longer constructed. These structures can be damaged by external factors such as earthquakes, floods, fires and wars. There are various studies that are carried out in order to determine the earthquake behaviour of the historical masonry arch bridges. The main objective of this study is to investigate the behaviour of the single span masonry arch bridge under earthquake effects by performing linear dynamic analyses. For this purpose, a single-span masonry arch bridge is considered as a numerical example. Three dimensional finite element model of the bridge has been created by using ANSYS finite element software into account with the macro modelling approach. Because of the location of the bridge, the acceleration records of the 2011 Simav and 2002 Sultandagi earthquakes were used as a seismic effect in the linear dynamic analyses. The displacements and maximum-minimum principal stresses of the bridge were obtained from the analyses and the seismic responses of the bridge were evaluated.

A computational fatigue study of the propagation of delamination in a composite wing rib has been conducted. A typical Boeing 747 rib having a circular hole with a semi-elliptical delamination was taken as the rib of interest; gust loads experienced during the cruise phase of flight were identified as the source of fatigue. A square section surrounding the circular hole comprising of laminated carbon–epoxy prepreg was isolated from the rib for computational analysis. The lack of analytical solutions for such a problem encouraged the use of the general-purpose finite element software ABAQUS. The delamination mechanism was simulated using the energy-based virtual crack closure technique in tandem with the Paris–Erdogan equation. The delamination propagation with respect to aircraft flight hours was obtained for the aircraft rib, with Mode III tearing dominating the delamination process. A parametric analysis was further conducted for various ply orientations where delamination modes were compared via a frame-based analysis. Significant differences in delamination propagation were observed, and better performing orientations for the given conditions were identified.

This article is part of a longer research-analytical work because it outlines the results and conclusions of the study according to the main topic of the research and the applied method. The central theme of the research is the dynamic stiffness of machine tools and the various methods for their determination. Following analytical analysis the machine tool natural frequencies were determined using a finite element software (ANSYS Workbench R19.1), which we now approach from a practical point of view, that is determined in the workshop by measurements. The results obtained are compared for each of the three methods.

Purpose The purpose of this study is to put forward a high-strength bolt end-plate connection of prefabricated concrete beam-column joint and carry out the pseudo-static test. Design/methodology/approach ABAQUS finite element software is used to study the fire resistance performance of high-strength bolt end-plate prefabricated joint. This mainly considers the influence of axial compression ratio, screw preload, end-plate thickness and steel hoop thickness. Findings The results show that the thickness of end-plate and steel hoop has a certain effect on the fire resistance. The change of screw preload has little effect on the fire resistance limit. Compared with the cast-in-place concrete beam-column joint, the deformation trend of column-beam end of the fabricated joint is basically the same as that of cast-in-place joint. Originality/value To study the mechanical performance of this kind of joint more comprehensively, the finite element software is used to study the prefabricated concrete beam-column joint with end-plates, and the effects of axial compression ratio, screw preload, end-plate thickness and steel hoop thickness on the fire resistance of joints are mainly considered.

A systematic parametric study has been conducted to investigate the behaviour of lean duplex stainless steel semi-elliptical hollow section members subjected to torsion, using finite element software, Abaqus. The finite element models were initially validated with reliable experimental results; upon which parametric study was conducted. Effects of various key parameters such as aspect ratio, curve length, size and thickness of cross-section were studied. Based on the finite element study, sections of higher aspect ratio, curve length, larger size, and higher thickness were found to have more torque carrying capacity. Available design equations for plates under shear loading were checked for their applicability to the design of semi-elliptical hollow sections subjected to torsion. An attempt has also been made to develop design equations for lean duplex stainless steel semi-elliptical hollow section under torsion, based on EN 1993-1-4: 2006 + A1. Additionally, design equations based on deformation based method (in line with continuous strength method) were also proposed. The proposed equations were found to give reliable results for design of lean duplex stainless steel semi-elliptical hollow section members under torsion.

A járműipar rohamos fejlődésével ugrásszerűen megnőtt az igény az új, illetve különböző módosításokkal továbbfejlesztett alapanyagokra. Ezen alapanyagokkal szemben számos elvárást támasztott az ipar, melyek közül az egyik legjelentősebb a felhasznált anyagok tömegének csökkentése. Ez mind gazdasági, mind pedig környezetvédelmi szempontból kiemelt fontossággal bír, mert az össztömeg csökkenésével a károsanyag kibocsátás is mérsékelhető. Mindemellett fontos, hogy az anyag eredeti szilárdsági tulajdonságait megtartsák, lehetőség szerint javítsanak rajta. A cikkben meghatározásra kerül egy nagyszilárdságú anyag (DP 600) alakítási határdiagramja, valamint annak felhasználása egy végeselemes (AutoForm R7) szoftverkörnyezetben. A tanulmány keretében bemutatásra kerül, hogy a végeselemes szoftverben kapott eredmények hogyan finomíthatók a modellezéshez felhasznált anyag anyagkártyájának meghatározása segítségével.

The article presents the results of computational modeling of a rigid pavement with load applied to the edge of the slab, for which a multipurpose software (ABAQUS / CAE) based on the finite element method is used. First, it is explained in detail how computational modeling is performed, taking as reference two types of rigid pavements (pavement with and without concrete shoulder). In the process, the main characteristics and hypotheses taken to model the load, the edge conditions and the characteristics of the materials are presented. The mesh density and the finite element type to be used are also analyzed, based on an experimental design. In order to reduce computation times, studies were conducted to make geometric simplifications to the domain. The final solution is contrasted with the Westergaard´s theory and the results of a finite element software already experimentally validated according to the bibliography (EverFE v2.24). Studies of some of the most important factors for pavement designing were conducted. Finally, graphs are shown in specific conditions of geometry and materials, which will serve as practical tools for use in design methods.

The comprehensive experimental study examining the general load-displacement behavior, stress distributions and shear stress-shear-displacement behaviors in the connection area when wood structural elements are combined with adhesive or adhesive with mechanical anchorages have been found in very limited number of studies in the literature. Therefore, an experimental study was planned. In this study, the general load-displacement behavior of the timber connection regions which are connected by adhesive and mechanical anchorages together with adhesive, with varying lengths of 180, 240 and 350 mm are investigated experimentally. Besides, the effect of changing the number and location of mechanical anchorages used in the connection area on the general load-displacement behavior and shear stress-shear-displacement behavior was also investigated. Using the load-displacement graphs obtained as a result of the experimental study, a generalized material model is proposed for the shear stress-shear-displacement interfacial adhesion surface for wood-wood junction points. This material model, which is proposed for wood-wood connection points with mechanical anchors, is a model that can be useful and can be used in the analysis of structural systems containing such connections using finite element software. It is thought that the overall capacity and load-displacement behavior of structural systems containing such connection points can be calculated more realistically using the proposed interfacial material model.

Instrumentation and monitoring are common methods to control the stability of large underground spaces. During monitoring underground excavations, it is usually impossible for the instrument to fully record the displacements taking place ahead of the tunnel. This occurs due to the fact that there is always a distance between the instrument and the excavation face, so some displacement are lost before the installation of the instruments. In this research, efforts have been made to estimate the loss displacement of the Azad Pumped Storage Powerhouse cavern in Iran, using combination of numerical method and instrumentation results. For this purpose, according to the excavated sequence (pilot tunnel, downstream slashing, and upstream slashing) the roof of the powerhouse cavern was modeled, using two-dimensional finite element software, verified by the results obtained from extensometer installed in the cavern's roof. The comparison of modeling and monitoring results indicates that the displacement occurrence recorded via the instrument is less than the modeling values. The most obvious reason is the displacement loss and impossibility in recording all displacements via the instrumentation. Then, employing the results of the adjacent instruments and displacements recorded by the cavern roof's instrument and utilizing a combination of modeling results, the amount of loss displacements in the cavern's roof was evaluated to be 40% of the total displacements. Afterward, employing analytical methods and fitting the curve on instrument's results, the outcomes indicate that the longitudinal deformation profiles obtained by Hoek equation has the best fit, confirming the 40% of the displacements that occurred before the installation of the instrument.

The concept of outriggers as a lateral load resisting system in high-rise structures has been used since decades. The relevance of outriggers gains prominence due to its efficiency in restraining the rotations in core wall which in turn reduces its bending moment and lateral deflection of the structure. Studies related to the behaviour of outriggers on tall buildings have been undertaken by various researchers, and condensing the concept, mechanism and its behaviour is vital in providing a proper guidance to researchers. Even though researchers have worked on buildings with outriggers, literatures mentioning the analysis of both conventional and virtual outriggers in the same building which acts like a hybrid outrigger system were underexplored. Therefore, this article discusses a review on the background of outriggers, classification of outriggers, parameters influencing the outrigger behaviour and introduces the concept of hybrid outrigger system in high-rise RCC structures. The efficacy of conventional, virtual and hybrid outrigger system is compared by modelling a 30-storey RCC building in a finite element software, ETABS, for both static and dynamic loads. The results from the comparative study showed that hybrid outrigger system may be used as an efficient lateral load resisting system.

Irritable bowel syndrome afflicts 10–20% of the global population, causing visceral pain with increased sensitivity to colorectal distension and normal bowel movements. Understanding and predicting these biomechanics will further advance our understanding of visceral pain and complement the existing literature on visceral neurophysiology. We recently performed a series of experiments at three longitudinal segments (colonic, intermediate, and rectal) of the distal 30 mm of colorectums of mice. We also established and fitted constitutive models addressing mechanical heterogeneity in both the through-thickness and longitudinal directions of the colorectum. Afferent nerve endings, strategically located within the submucosa, are likely nociceptors that detect concentrations of mechanical stresses to evoke the perception of pain from the viscera. In this study, we aim to: (1) establish and validate a method for incorporating residual stresses into models of colorectums, (2) predict the effects of residual stresses on the intratissue mechanics within the colorectum, and (3) establish intratissue distributions of stretches and stresses within the colorectum in vivo. To these ends we developed two-layered, composite finite element models of the colorectum based on our experimental evidence and validated our approaches against independent experimental data. We included layer- and segment-specific residual stretches/stresses in our simulations via the prestrain algorithm built into the finite element software febio. Our models and modeling approaches allow researchers to predict both organ and intratissue biomechanics of the colorectum and may facilitate better understanding of the underlying mechanical mechanisms of visceral pain.

International audience; Structural and nonstructural members are always encountered with extreme loading conditions. In case of nonstructural members, the failure happens much sooner due to lack of load capacity. The nonstructural elements are not designed for structural loading conditions. However, they might be impacted to other loading types such as fire. In recent years, the use of 3D panel is one of the most common partitions in the world. In this research, the effect of fire on 3D panel partitions is presented. To achieve this goal, ABAQUS finite element software is employed to simulate the 3D panel. The 3D panel is embedded inside steel frame. In order to have an accurate result, two validations are performed including steel frame and the steel frame with 3D panel. In the study, 5 different fire loadings 200, 400, 600, 800 and 1000°C are applied into the model. Results include load-displacement diagram and stiffness and ductility factors. The results indicated that as fire load increases, the stiffness and ductility factor are reduced.

The present paper focuses on the study of deformation behavior of steel concrete composite (SCC) girders with partial shear interaction. The main objective of this work is to bring out the relative significance of the partial shear interaction with respect to full interaction, which has been addressed with the help of parametric study considering various influencing parameters such as, degree of shear connection, span length, type of loading, distribution of shear stud connectors, geometry of steel girder, yield strength of structural steel and concrete grade. The parametric study has been carried out using a simplified numerical modelling technique with the help of commercially available finite element software SAP2000. The numerical modelling involves simulation of composite action between the concrete deck and the steel girder in the SCC girder, which has been carried out by using various elements such as, beam elements, rigid link elements and spring elements. Further, a comparative study has been carried out to study the accuracy of numerical model with the available analytical models. The results of the numerical model are also compared with the results of the equations given in several national codes to calculate deflections, to study the efficacy of the codal provisions. It is seen that the various aforementioned parameters have considerable influence on the deformations of SCC girders. It is also seen that the change in distribution type of shear stud connectors considerably reduce their number without significantly affecting the deformations of SCC girder.

This paper studies the influence of different longitudinal top reinforcement detailing on the behaviour and punching capacity of flat slabs. Experimental and numerical studies were carried out. The experimental campaign consisted in testing three reinforced concrete slabs 2.20 m wide with a thickness equal to 0.15 m. The numerical study was conducted using the non-linear finite element software ATENA 3D. Using numerical models, which were calibrated using the experimental tests, a parametric study was carried out to include other design solutions beyond the tested ones. The parameters that were changed in this parametric study were the steel reinforcement ratio, the concrete strength and the detailing of the top steel reinforcement, namely using a solution with uniform distribution and other with a higher concentration of reinforcement near the column. Finally, the results were compared with predictions obtained using some of the existing codes (Eurocode 2 and Model Code 2010). From this study it can be concluded that concentrating the top flexural reinforcement, keeping the same total amount of top longitudinal reinforcement, results in a stiffer response, an increment in the punching resistance, and a decrease in the maximum vertical displacement.

This paper presents a numerical, experimental, and theoretical study on the behavior of concrete-filled square double-skin steel tubular (CFDST) stub columns under axial compressive loading. Firstly, three-dimensional solid model of CFDST stub columns was established by ABAQUS finite element software and verified through the existing experimental results. Then a full-scale model was established to investigate the influence of various parameters on ultimate bearing capacity and internal and external compressive stress of concrete. By considering the confinement coefficient, the practical calculation formula for the bearing capacity of CFDST stub columns was proposed. Finally, the experimental research on the mechanical properties of two large hollow ratio CFDST stub columns under axial compression was carried out. And the experimental research further verified the applicability of the FE model and calculation formula of the CFDST stub column with large hollow ratio under axial compression.

PurposeAnchorage with concrete bearing pad is commonly used in Iran for stabilization of excavations because of the ease of construction, less costs and less time consumption than the soldier pile method. In this method, a wall facing which includes the concrete bearing pads at the location of the anchors and a shotcrete layer between the bearing pads is constructed parallel to the excavation operation similar to the nailing method.Design/methodology/approachIn this paper, using the finite element software Abaqus, a three-dimensional model of the above-mentioned type of wall is constructed, and the effect of spacing and size of bearing pads on the wall behavior is discussed.FindingsAccording to the obtained results, the size of the concrete bearing pads has little effect on wall deformations, but the internal forces and bending moments developed in the shotcrete layer between the bearing pads are greatly influenced by the bearing pads dimensions and spacing.Originality/valueOwing to the discrete elements of the wall facing, the behavior of this system is completely three-dimensional.

Purpose The purpose of this paper is to determine how the shape of the container affects the efficiency of a traveling magnetic field (TMF) stirring. Design/methodology/approach The modeling approach is based on finite element software Comsol which includes harmonic electromagnetic (EM), transient CFD and particle tracing modules. For evaluating efficiency of stirring the particle, homogenization parameter is used. Findings It has been determined that the use of an elliptical cylinder-shaped vessel allows better heat removal from the side surface and, at the same time, the stirring efficiency does not drop significantly. Practical implications The results of the work can be used in the design of EM stirring installations in which exothermic reactions occur. Originality/value The transient simulation of particle transport in a TMF-driven melt flow gives the opportunity to estimate the efficiency of stirring process in different vessel shapes.

In this study, an analytical model for calculation of the maximum socket depth of bolts having shaft diameter smaller than socket diameter was introduced. A representative bolt was chosen and maximum socket depth satisfying the minimum ultimate tensile strength was calculated by the developed analytical model. The analytical findings were also compared with numerical simulations for validation. Numerical studies were carried out by using Simufact.forming finite element software. The maximum socket depth estimated by using the developed analytical model was in good agreement with the numerical results. The obtained critical socket depth through the analytical model was 1.4% safer compared to numerical simulation results. Therefore, it was concluded that the developed analytical model could be used to estimate the critical socket depths of bolts having shaft diameter smaller than socket diameter. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo

The purpose of this work is to develop a computational method for adhesively bonded composite structures lifetime assessment. A cohesive zone model – based formulation including fatigue damage is selected. The model is implemented in the finite element software Abaqus through user subroutine. Numerical simulations are subsequently performed for the mode I crack propagation case. Validation of available experimental data for both quasi-static and high-cycle fatigue tests is successfully achieved.

Graphene emerges as an important class of material for Nanoelectromechanical System (NEMS) because of their exceptional mechanical properties. We have systematically investigated static and dynamic characteristics of an electrostatically actuated graphene bridge resonator. The graphene bridge resonator has been modelled in finite element software as a 3D device. We have analysed the effect of internal stress and electrostatic actuation force on static and dynamic characteristics of the graphene bridge resonator. Internal stress can be built-up in the graphene sheet due to variation in operating temperature of a NEMS device. We have also investigated the effect of variation of size and nature of end boundary conditions on the static and dynamic characteristics of the electrostatically actuated graphene bridge resonators. It has been found that the natural frequencies of bridge resonator can be considerably tuned by variation of electrostatic actuation force and internal stress. We have also observed that the choice of boundary conditions has a significant role in characterization of graphene bridge resonators.

Purpose The purpose of this paper is to describe the structure of nonlinear dampers and the dynamic equations, and nonlinear realization principles and optimize the parameters of nonlinear dampers. Using the finite element method to analyze the seismic performance of the frame structure with shock absorber. Design/methodology/approach The nonlinear shock absorber was installed in a six-storey reinforced concrete frame structure to study its seismic performance. The main structure was designed according to the eight degree seismic fortification intensity, and the time history dynamic analysis was carried out by Abaqus finite element software. EL-Centro, Taft and Wenchuan seismic record were selected to analyze the seismic response of the structure under different magnitudes and different acceleration peaks. Findings Through the principle study and parameter analysis of the nonlinear shock absorber, combined with the finite element simulation results, the shock absorption performance and shock absorption effect of the nonlinear energy sink (NES) nonlinear shock absorber are given as follows: first, the damping of the NES shock absorber is satisfied, and the linear spring stiffness and nonlinear stiffness of the shock absorber are based on the relationship k1=kn×kl2, so that the spring design length is fixed, and the linear stiffness of the shock absorber can be obtained. The nonlinear shock absorber has the characteristics of high rigidity and frequency bandwidth, so that the frequency is infinitely close to the frequency of the main structure, and when the mass of the shock absorber satisfies between 0.056 and 1, a good shock absorption effect can be obtained, and the reinforced concrete with the shock absorber is obtained. The frame structure can effectively reduce the seismic response, increase the natural vibration period of the structure and reduce the damage loss of the structure. Second, the spacer and each additional shock absorber have a small difference in shock absorption effect. After the shock absorber parameters are accurately calculated, the number of installations does not affect the shock absorption effect of the structure. Therefore, the shock absorber is properly constructed and accurately calculated. Parameters can reduce costs. Originality/value New shock absorbers reduce earthquake-induced damage to buildings.

Betonarme yapı ve yapı elemanları, kullanım süreleri boyunca çevresel faktörler, uygun olmayankullanım, deprem etkisi gibi çeşitli yük etkilerine maruz kalırlar. Düşük malzeme dayanımı ve kalitesiyapının taşıma gücünü azaltan en önemli faktördür ve diğer etkenlerle birlikte değerlendirildiğinde yapıve yapı elemanlarında hasar oluşumunun en önemli nedenidir. Bu nedenle yapıların performansının hasardüzeylerine göre belirlenmesi ve uygulanacak onarım/güçlendirme yöntemine karar verilebilmesi içinmevcut malzemelerin kalitesinin belirlenmesi ile birlikte bir ön tasarım çalışması yapılmasıgerekmektedir.Çalışmanın en önemli adımlarından birisi, yapının tamamının ya da belirli bir bölümünün sayısalmodelinin hazırlanması işlemidir. Hassas bir sayısal model oluşturmak için malzemelere ait bünyeselbağıntılar ile elemanların bireysel davranışının gerçekçi bir şekilde tanımlanması gerekmektedir. Buçalışmada sonlu elemanlar modelinin deneysel sonuçlara olan uygunluğu araştırılmıştır. Bu amaçlayazarların daha önce deneysel çalışmalarını gerçekleştirdikleri yalın ve güçlendirilmiş betonarme kirişlerile literatürde betonarme kirişler için yapılan deneysel çalışmaların modellemesi sonlu elemanlar yöntemiile yapılarak elde edilen sonuçlar deneylerden elde edilen sonuçlarla karşılaştırılmıştır. Araştırmacılar,daha önce yığma duvarların sayısal modellenmesinde kullandıkları elasto-plastik hasar teorisi yaklaşımınıbetonarme kirişler için geliştirerek uyarlamışlardır. Çalışmada LUSAS sonlu elemanlar yazılımıkullanılarak iki adet yalın ve üç adet Lifli Polimer (LP) sargılı kirişlerin eğilme altındaki davranışlarıbaşarı ile modellenmiştir., Reinforced concrete structures and structural elements are subjected to various load effectsduring their lifetime, such as environmental factors, improper handling, earthquake effects. Low materialstrength and low quality are the most important factors that reduce the load carrying capacity and whenevaluated together with other factors, it is the most important cause of damage to the structures andstructural elements. Therefore, in order to determine the performance of the structures according to thedamage levels and decide on the repair / strengthening method to be applied, a preliminary design studyhas to be done with determining the quality of the existing materials. One of the most important steps ofthis work is to prepare the numerical model of a complete structure or a specific part of the structure. Inorder to develop a precise numerical model, it is necessary to define the behavior of the elements with theconstitutive relations of the materials realistically. In this study, the numerical models of the reinforcedconcrete beams which authors had already performed the experiments and reinforced concrete beamssubjected to experimental loads in the literature are modelled and the results are presented. Researchersadopted the approach of elasto-plastic damage theory for reinforced concrete beams previously used inthe numerical modeling of masonry walls. In this study, the flexural behavior of two unreinforced andthree Fiber-reinforced polymer (FRP) strengthened beams with using LUSAS finite element softwaresuccessfully modeled.

Heinz Isler as the most famous contemporary shell designer has widely employed physical pre-modelling techniques for construction of many concrete shell structures. Through the physical approach to optimal form finding, Isler accomplished shell structures with robust performance. It would be interesting and beneficial to re-assess Isler’s shells, hence, this article attempts to study the structural performance of eight notable shells of Isler. Through reverse engineering and by the assistance of Rhino, MATLAB and Grasshopper, the precise geometry of Isler’s selected shells were modelled for the finite element analysis under their self-weight. The structural analysis was performed, with the parallel use of finite element software SAP2000 and Abaqus. The identical results of the two packages, further confirmed the accuracy of the analysis. The essential properties of various forms of the shells and their differences in behaviour were pinpointed and discussed within the calculations and the results were compared with the data of the genuine published references on Isler’s works. The internal forces, the amount of von Mises stresses, support reactions and the buckling loads of the shells are explored. The analyses revealed that, despite of their major membrane action, all the shells had negligible amount of bending moments, especially near the supports. However, in general, all the shells exhibited an appropriate performance under the applied actions. But, at the same time, they exhibited different buckling behaviour as a probable source of instability in them.

Given the importance of geometry in structural analysis of masonry arches, and taking into account the relationship between stress and deformation, this article presents the influence of the elastic modulus in the collapse mechanism and load for the more common geometries within the masonry arches, considering the effect of the rigidity in the numerical convergence, and the computational cost, within the ABAQUS finite element software. For this, four geometries subjected to ten different elastic modulus are analyzed. The results obtained by the ABAQUS Finite Element Software are compared with the software based on the rigid blocks theory, LimitState Ring.

In this research, response of steel beam-to-column bolted connections to blast loading is investigated. Nonlinear analyses of the connections are performed using the finite element software ABAQUS. In order to demonstrate the accuracy of the finite element modelling, an experimental test of a steel beam-to-column bolted connection is modelled. Comparison of the obtained result from the modelling with that of the corresponding experimental test verifies the modelling. Then, a 5-storey steel building is designed using ETABS software from which a beam-to-column connection of the ground floor is selected for the nonlinear analysis in ABAQUS. Thereafter, the components of the selected connection are designed. Finally, the connection is nonlinearly analysed considering parameters as the distance from the blast centre (2.5 m, 5 m, and 10 m) and blast power (500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive). Effects of these parameters on the response of the connection are evaluated. Failure modes of the connections are assessed, too.

The bolted spherical nodes are widely used as member joints of lattice shell structures. With long-term service in a corrosive environment, the bearing performance degradation of these nodes due to corrosion especially pitting corrosion is threatening the safety of the entire structure. The paper presents a pilot study on the bearing performance of the bolt-sphere joint portion in the bolted spherical node with stochastic pitting corrosion damage. Aided by the finite element software ABAQUS, the bolt-sphere joints are modeled in 3D incorporating the helical thread contact and progressive damage of material. The pitting corrosion is induced by explicitly adding uniform distributed pits on the intact (pit-free/uncorroded) model while the pit depth is depending on the corrosion rate and service time. With the experimental data from the uniaxial tensile bearing capacity tests on uncorroded joints and the subsequent failure mode characterization, the load-displacement responses and simulated fracture surfaces by the corresponding virtual tests on the intact model are validated. Then the virtual tests are extended to the corroded joints with different corrosion time, by which the corresponding load-displacement curves and simulated failure process are obtained. It is found that the elastic axial stiffness is degenerated by 2.6% and 4.1% and the ultimate bearing capacity is degraded by 3.1% and 5.6%, after 50 years and 100 years of corrosion, respectively. The simulated fracture surfaces indicate that the domination of shear damage is gradually weakened by the increase of pits, leading to a more ductile fracture and a flatter cup-cone fracture surface.

The cracks caused by fracture of concrete lining have adverse impacts on the tunnel structure, considering the influences of serviceability and durability. In this paper, a particular case study of a newly built tunnel structure is presented for a certain amount of longitudinal cracks, focusing on the inducement of cracking and effect of concrete fracture. An integrated field investigation is implemented to characterize the spatial distribution of longitudinal cracks and detailed site situations, and the temperature difference of concrete within the lining is as inducement according to a series of reliable experiments. To further understanding of the lining structure performance influenced by fracture behaviors, two groups of numerical models based on finite element software are simulated for reinforced concrete and concrete cross sections, respectively. Among the numerical models, a simplified crack model is applied for damaged lining structure, considering the realistic width and depth of cracks. Ultimately, different safety factors are adopted not only for verifying the stability of cracks but also for getting the differences of structural safety under maintenance work. Situations of crack are in accordance with the real conditions in situ, besides the maintenance work is proved as essential and effective methods in this damaged tunnel.

This paper focuses on the hysteretic assessment of steel-concrete composite shear walls with reinforced concrete on one side of the steel plate. Finite element software ABAQUS is utilised to conduct this research. An experimental test on a composite shear wall is simulated to do the verification of the modelling. Then, modelling result is compared with the experimental test result which shows an insignificant difference between them and therefore uncovers the accuracy of the modelling. Thereafter, different parameters are considered to investigate their effects on the response of the walls. Thickness of reinforced concrete, steel plate thickness, and number of shear studs are studied as parameters. It is concluded that changing reinforced concrete thickness and number of shear studs do not considerably affect the ultimate load capacity, ductility, and energy dissipation of the walls. However, increasing the steel plate thickness enhances the ultimate load capacity, ductility, and energy dissipation. In addition, out-of-plane displacement of the walls is evaluated.

This paper presents simple method to estimate the strength design of reinforced concrete beam sections based on structural safety and reliability. Irregular beam shaped sections are commonly used nowadays in the construction industry. This study reveals the simplified method to analyze and design the different irregular shaped beam sections. In this study, the selected irregular beam shaped sections are divided mainly into three groups, beams with straight edges, beams with sloped edges and circular beams. Each group contains the most commonly used beam shaped sections in that category. Six beams sections (B-1 to B-6) are selected for group-1 whereas five beam sections (B-7 to B-11) and a circular beam section (B-12) are chosen for group 2 and 3 respectively. Flexural beam formulas for three groups of reinforced concrete beams are derived based on section geometry and ACI building code of design. This study also analyzed numerical examples for some of the sections in each group category using the proposed simplified method to determine the strength design of the irregular beams. The results obtained using simplified method for all of the three groups are compared with the finite element software (SAP v2000). The percentage difference of simplified method with the finite element software ranges within 5% to 10%. This makes the simplified method for irregular shaped beam sections quite promising.

The current study presented a method to estimate seismic response of inter-story drift in tall buildings. Inter-story drift is obtained using combined mode-acceleration equations via modeling tall buildings through flexural and shear cantilever beams’ equations, and estimating dynamic components of tall buildings. In the provided equation to calculate seismic response of inter-story drift, it is necessary to know details of the building, which makes it easy and expedites the analysis. Inter-story drift of 10-, 15-, and 50-story buildings for three earthquake accelerograms was estimated using the provided equation, and via finite element software OPENSEES, the equation was verified. Results comparison showed that the equation provided a good approximation, which can be used instead of modeling, to calculate inter-story drift. In addition, the comparison between the calculated inter-story drift with those of the approximate method and finite element method showed that the mode-acceleration method was close to the accurate solution even using few modes.

As part of the ongoing China Fusion Engineering Test Reactor (CFETR) studies, this work focused on the study of the electromagnetic (EM) loads distribution on inboard (IB) and outboard (OB) blanket vertical segments. In this paper, a major central disruption scenario with a 36-ms linear current quench was performed in the ANSYS finite element software. EM forces and moments, both on the single module and the complete blanket segment, were calculated for the updated helium-cooled ceramic breeder (HCCB) blanket. Furthermore, the effect of EM loads with respect to poloidal segmentations on the back plate (BP) was studied. Results show that the EM forces and moments in the IB blanket barely changed, but in the OB blanket, great changes occurred. With poloidal segmentations increasing, EM forces loads on the BP will be reduced. This paper may provide important data to support subsequent optimization of the BP of CFETR and could also be a technical reference for other fusion organizations.

A traversal algorithm considering both of the mesa interval and the entire area of the mesas was applied to find a vertical cavity surface emitting laser (VCSEL) array with minimal heat coupling factor. An optimized array was obtained and modeled in finite element software to simulate the thermal distribution. A conventional circular and an optimized array were fabricated. The maximum output power of optimized array is 14.3% higher than the conventional array and reaches 1.6 W operating in continuous wave (CW) mode. The wavelength shift of optimized VCSEL array is slightly slower than the reference device although its higher power.