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1
Li, Zhi Miao, Ju Bao Liu, Min Luo, and Qiang Zhang. "Dynamic Finite Element Analysis and Experimental Study of Rotating Column in Cylinder." Applied Mechanics and Materials 229-231 (November 2012): 453–56. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.453.
Повний текст джерелаАнотація:
Rotary slender column in cylinder is a special structure in oil engineering. It contacts with outer cylinder and interacts with its inner pipe fluid and outer annular fluid. A partitioned coupling model was founded by dispersing slender column into beam element, dividing fluid domain into some sections, dispersing fluid section into hexahedron unit and transfer method of the information of coupling interface was described. Dynamics experimental device of column-liquid interaction was built to do column rotating test with considering the displacement and force boundary conditions of rotating column and testing axial excitation force of bottom column, axial acceleration of head column, transverse displacement of columns and collision and contact forces between inner columns and outer pipeline. The maximum absolute error between experimental results and numerical results is 0.31mm and this research provides the methods of numerical simulation and experimental study.
2
Wang, Bin, Peng Ju Sun, Xin Wang, and Ya Feng Xu. "Finite Element Analyze on the CFRP Steel Reinforced Concrete Filled with Steel Tube Column under Biaxial Load." Advanced Materials Research 680 (April 2013): 172–76. http://dx.doi.org/10.4028/www.scientific.net/amr.680.172.
Повний текст джерелаАнотація:
The paper focuses on the research of mechanical behavior of the CFRP steel reinforced concrete filled with steel tube column under biaxial load. The authors make a simulated analysis mode with the general finite element analyze software, ABAQUS. By the way of unit selecting, meshing, contact setting, the mode is calculated by the ABAQUS/Standard which is used to analyze the mechanical behavior of the specimens. Based on comparing the load-displacement curves under different axial compression ratios, it can conclude that with the increasing of compression, the ultimate load reduces obviously. At the same time, the ductility coefficient also descended slowly. All the ductility coefficients of different specimens are all larger than 2, which meet the code very well. So the mechanical behavior of the column is very well.
3
Savin, Sergey. "NUMERICAL ANALYSIS OF REINFORCED CONCRETE BEAM-COLUMN JOINT UNDER ACCIDENTAL IMPACT." Journal of the Serbian Society for Computational Mechanics 15, no. 1 (November 1, 2021): 149–66. http://dx.doi.org/10.24874/jsscm.2021.15.01.10.
Повний текст джерелаАнотація:
The purpose of this study is to create a universal computational model of a plane-stressed joint element, which could be implemented as a special finite element of the beam-column subassembly integrated into the FEA procedure to improve its accuracy. The combination both of the finite element method and the finite difference method has been accepted to simulate the structural behavior of monolithic reinforced concrete joints of building frames. The finite difference method is used directly for analysis the stress-strain state of a 2D stressed member of a monolithic joint, and the FEM is used for preliminary obtaining the conditions on the contour of this plane stressed member. The proposed model allows considering the discrete reinforcement, as well as the disruption of the adhesion of the reinforcing bars to concrete matrix along the contact surface. For the purposes of implementing the model, an algorithm for the stress-strain state analysis of the beam-column joint is proposed. An example of calculating an experimental frame unit based on the proposed approach is considered.
4
BĄK, KRZYSZTOF, JOANNA KOWALCZYK, ANNA WOLSKA, MARTA BĄK, and LUCYNA NATKANIEC-NOWAK. "Iron and silica enrichments in the middle Albian neptunian dykes from the High-Tatric Unit, Central Western Carpathians: an indication of hydrothermal activity for an extensional tectonic regime." Geological Magazine 155, no. 1 (March 3, 2016): 1–19. http://dx.doi.org/10.1017/s0016756815001132.
Повний текст джерелаАнотація:
AbstractStudies dealing with the response of subaqueous volcanic and hydrothermal activities to carbonate sedimentation in hemipelagic environments affected by tectonic processes are comparatively rare. Here, a microfacies record with combined chemical data from the neptunian dykes found at an intrabasinal ridge (Tatric Ridge; Carpathian domain of the Western Tethys), close to a source of alkaline volcanism with possible hydrothermal vents (Zliechov Basin), is presented. The characteristic features of the neptunian dykes, up to 20 cm thick, in the middle Albian echinoderm-foraminiferal limestones (Tatra Mountains, Inner Carpathians) are their red fillings. Microprobe and x-ray diffraction analyses show that this reddish material, partly mixed with sparitic clasts coming from the host limestone, consists mainly of hematite crystals which are associated with low crystalline silica and quartz. The microfacies data suggest that the reddish infillings of the dykes is partly related to dissolution processes inside the fissures that could have taken place during the transport of FeCl3 fluids together with silica gel. The fluids could have been derived from hydrothermal vents occurring along the extensional faults in the neighbouring Zliechov Basin. Rare Earth element (REE) signatures of the reddish infill (i.e. low values of total REE content, chondrite- and Post-Archean Australian Shale-normalized REE + Y patterns with negative Ce anomaly) and a high Y/Ho ratio suggest authigenic removal of REEs from the water column. This suggests that the fissures were open to the sea bottom and were in contact with sea water during their filling.
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Borushchak, L. O., and B. B. Vynnychuk. "IMPROVEMENT OF THE CONSTRUCTION AND COMPUTER DEVICE INVESTIGATION FOR THE PROCESSING OF BLOWOUT-PREVENTION HARDWARE EQUIPMENT." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 1(46) (June 26, 2019): 16–24. http://dx.doi.org/10.31471/1993-9965-2019-1(46)-16-24.
Повний текст джерелаАнотація:
The research deals with the problem of blowout equipment test for tightness before implementation. The indicated equipment includes a stem, a system of pipelines with valves and a control system. The classic test procedure requires a mobile pumping installation that provides a pressure of 35 MPa.The cost of such tests is rather high. For testing without a pump unit, a design of a device for increased tightness has been developed, including a sealing unit of the mouth from the main column and a piston unit for creating high pressure in the test volume. Generation of a high pressure occurs by lifting the piston with a winch, mounted on the well. Disadvantages of the previously proposed design of the device are as follows. There is a considerable friction between the steel moving parts of the sealing unit. Mostly these are the pairs of a plug and a cup, and a chuck and a cone. Tightness is provided by rubber ring sleeves. Exceedence of axial load on cones causes destruction of sealing rings. The authors of the article improved the design of the sealing unit in the following way: a ball thrust bearing was seated between the ends of the pressure plug and the bottom cup and as a result the sliding friction was replaced with sliding friction. On the outer surfaces of the opening cones in contact with clamping blades, it is proposed to paste a tissue antifriction material of type Nafthlene or equivalent. The friction coefficient in such pairs is next lower order than in steel to steel pairs. The computer model of the device has been created in the Solid Works environment. The computer researches of the loading process of components of the sealing unit in the simulation program based on the finite element method were performed. As a result of the research, recommended values of the axial force, required to create a screw pair of a stem and a plug for sufficient radial axial deformation of elastic cuffs with the simultaneous non-admission of their destruction were identified. Also, the design dimensions of the pressure cups of the device were optimized, namely, the mutual axial placement of the end face, which presses on the cone, and the tapered belt, compressing the sealing ring. The determination of these parameters by an experiment is a long and expensive process.
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Bonhomme, M., F. Rogalla, G. Boisseau, and J. Sibony. "Enhancing Nitrogen Removal in Activated Sludge with Fixed Biomass." Water Science and Technology 22, no. 1-2 (January 1, 1990): 127–35. http://dx.doi.org/10.2166/wst.1990.0142.
Повний текст джерелаАнотація:
To upgrade existing activated sludge treatment plants, different techniques that would remove an important flux of nitrogen rapidly on a great number of units were investigated. Nitrification with conventional activated sludge systems requires considerable multiplication of tankage volume. The necessary investment and space is not always available, especially since many older plants are now in urbanized areas. To lower the nitrogen load in receiving water, the first priority should be to obtain partial nitrogen removal with existing plants, using methods that are simple to adapt.Three techniques were tested on large scale: submerged elements in aeration basin to add fixed biomass, contact stabilisation that allows a higher sludge age in the same tankage volume, and adding submerged biotower packings as a tertiary aeration stage. In a full scale unit (4000 m3/d), one complete section of the plant fitted with biofilter packing was operated in parallel with a similar unmodified section as reference. The volume occupied by the fixed beds was varied between 20 and 40 % of the tank. The submerged elements improved removal efficiency, to maintain effluent quality at higher loadings or obtain lower residual pollution values in existing plants. The biofilm evolution and the hydraulic behaviour of the packing was followed. No significant change in sludge settleability was observed, but fixed biomass addition reduced sludge production because of a lower overall mass loading. The resulting higher sludge age allowed the ammonia oxidizers to remain in the mixed population beyond usual F/M limits, but no installation of nitrifiers on the support media could be observed. To verify the limits of immersed plastic surfaces for nitrification, an aerated column was fed with effluent of a highly loaded activated sludge plant. In opposition to carriers submerged in mixed liquor, nitrifier attachment was obtained, and COD and SS removal for effluent polishing was achieved. With a carbon loading exceeding 1,5 kg COD/m3 d, a maximum oxidation rate of 0,4 kg N-NH4/m3 d could be obtained. A pilot unit was tested to assess the potential volume reduction for nitrogen elimination by contact stabilisation. This configuration stores the highly concentrated return sludge in a reaeration basin, and keeping only the minimum detention time in the contact basin to obtain nitrification. Also, an increased carbon load in the contact basin enhances denitrification. For urban wastewaters with a COD/N ratio of about 10, complete oxidation and partial removal of nitrogen were obtained with a volume loading of 1,5 kg COD/m3 d. Nitrogen removal rates of 0,15 kg N/m3 d were measured both in the anoxic and the aerobic part of the contact basin. The contact stabilisation mode was then tested on full scale combined with submerged biomass carriers. A consistant nitrogen elimination of 50 % was obtained with aeration detention times of about 4 hours.
7
Brinkman, F. P., T. V. Kane, R. R. McCullough, and J. W. Miertschin. "Use of Full-Field Simulation to Design a Miscible CO2 Flood." SPE Reservoir Evaluation & Engineering 2, no. 03 (June 1, 1999): 230–37. http://dx.doi.org/10.2118/56882-pa.
Повний текст джерелаАнотація:
Summary A study using full-field reservoir modeling optimized the design of a miscible CO2 flood project for the Sharon Ridge Canyon Unit. The study began with extensive data gathering in the field and building a full-field three-dimensional geologic model. A full-field simulation model with relatively coarse gridding was subsequently built and used to history match the waterflood. This waterflood model highlighted areas in the field with current high oil saturations as priority targets for CO2 flooding and generated a forecast of reserves from continued waterflooding. Predictions for the CO2 flood used an in-house four-component simulator (stock tank oil, solution gas, water, CO2. A full-field CO2 model with more finely gridded patterns was built using oil saturations and pressures at the end of history in the waterflood model. The CO2 model identified the best patterns for CO2 flooding and was instrumental in selecting a strategy for sizing the initial flood area and in determining the size, location, and timing of future expansions of the CO2 flood. Introduction The Sharon Ridge Canyon Unit (SRCU) is located in West Texas, about 70 miles northeast of the city of Midland. The Unit covers 13,712 acres. Fig. 1 shows the Horseshoe Atoll, a trend of more than 40 oil fields covering several West Texas counties. SRCU is geologically continuous with the Diamond M Unit and the giant Kelly-Snyder Field (SACROC Unit) to the northeast. Production is from the Canyon Reef formation, a thick carbonate buildup of late Pennsylvanian Canyon and Cisco age, and occurs at an average depth of 6600 feet. There are active CO2 floods in this formation at SACROC, Reinecke, and the Salt Creek field. Sharon Ridge was discovered in 1949 and developed on 40 acre spacing by 1953 with about 340 wells. The reservoir initially contained undersaturated oil at 3135 psi. Production was by expansion drive until 1952 when pressure fell below the bubble point of 1850 psi over most of the field. In 1955, the field was unitized and a peripheral waterflood was started to stabilize reservoir pressure. The waterflood is now at a mature stage with oil recovery approaching 50% of the original oil-in-place (OOIP). There has been limited infill drilling with 22 wells drilled at 20-acre spacing. Screening studies identified SRCU as a good candidate for a miscible CO2 flood project. These studies included core flood displacements, pattern element simulation models, and detailed evaluations of similar fields with CO2 floods. Laboratory core displacements showed a remaining oil to waterflood of over 40% with subsequent injection of CO2 reducing oil saturation to less than 10%. Simulations with small element models have also shown significant incremental oil recovery from injection of CO2 at SRCU. SRCU has reservoir properties similar to SACROC which has reported significant additional oil recovery from miscible CO2 flooding (Ref. 1). The goal of full-field modeling was to design a miscible CO2 flood with maximum economic potential. Key issues for project design include the amount and location of remaining oil, reservoir sweep efficiency, flood rate, gas injection volume, strategy for handling increased produced gas, and projection of continued secondary operations. To address these issues, we built three different full-field three-dimensional (3D) models: geologic model, coarse-grid waterflood model, and fine-grid CO2 flood model. Recent advances in computer technology made this approach possible as opposed to the prior approach of running type-element models and scaling up those results to field rates. The approach of using field-scale simulation models to study optimizations for another CO2 flood in West Texas has been reported in Ref. 2. Thus, advancing technology and prior experience led us to embark on this ambitious approach to use full-field modeling to design our CO2 flood. Geologic Modeling Geology. The reservoir is a thick carbonate buildup that is predominately limestone. Fig. 2 shows the structure on the top of the reservoir. Geographic areas of the field have been named: North End, South End, and Southeast Pinnacle. The topography is extremely variable, with the hydrocarbon column averaging 115 feet and ranging to a maximum of 450 feet in the South End area of the field. A large portion of the North End has over 90 feet of gross reservoir thickness above the original oil-water contact. Table 1 is a summary of reservoir rock and fluid properties. The reservoir has been subdivided into five depositional sequences or zones, four of which are shown in Fig. 3. The lower zones (4, 5) are found over almost the entire field while upper zones (1, 2, 3) are more areally restricted. Zones are usually separated by intervals of low porosity limestone with few shales in the reservoir. Most wells drilled during initial field development did not penetrate the entire reservoir, thus limiting description of the lower zones. A more detailed discussion of the geologic setting and depositional facies is available in Ref. 3. Model Design. Building a full-field 3D geologic model of SRCU presented several unique challenges, including having modern porosity logs on only a few wells and only 90 full penetrations of the reservoir. To address this problem of limited data, an extensive data acquisition program was implemented. This program included deepening 19 wells, coring 11 wells, and obtaining 49 miles of new two-dimensional (2D) seismic lines. After gathering these data, all new and old core, well log, and seismic data were integrated to develop a sequence stratigraphic reservoir framework.
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Sorokin, V. V. "Calculation of Start-Up Time of Passive Catalytic Hydrogen Recombiner of Localization Safety System of a Nuclear Power Plant Equipped with VVER." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 65, no. 1 (February 2, 2022): 67–75. http://dx.doi.org/10.21122/1029-7448-2022-65-1-67-75.
Повний текст джерелаАнотація:
The hydrogen removal system ensures hydrogen safety. At a VVER nuclear power plant, it consists of passive catalytic hydrogen recombiners. The calculation of devices is of great importance for safety justification, since the complex conditions of an accident at a power unit are not reproducible in experiments. The recombiner consists of a casing and a cassette with catalytic elements, the design of which ensures the passage of a gaseous medium through the device. Upon contact with the catalyst, a chemical reaction of hydrogen and oxygen compounds occurs, accompanied by the release of heat; as a result, the concentration of hydrogen under the shell decreases. The problem is starting from a cold state since the activity of the cold catalyst is low, and the thrust is not observed until the catalyst is heated and a column of warm gas is formed inside the device. The transition from the cold state to the working state takes a certain time, during which the recombiner performance is below nominal. The start-up time is a parameter that is important in terms of safety. The article calculates the start-up time of a hydrogen recombiner with a catalytic block in the form of equidistant parallel catalytic plates. Local cross-sectional averages and transmission coefficients are used, the latter taking into account the influence of free convection and chemical reaction. The gas velocity is determined by the balance of buoyant and resistance forces. The calculated data and the data known from the scientific and technical literature coincide satisfactorily. As a conservative estimate of the start-up time of the recombiner, it is recommended to use the value of 300 s. An increase in temperature practically does not affect the start of the recombiner with an active catalyst, an increase in the concentration of hydrogen accelerates the start, and a decrease in pressure slows it down. The results obtained in the study can be used in the justification of the safety of VVER nuclear power plants and the examination of reports on the justification of the safety of power units.
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Bouboulas, Athanasios, and Nikolaos Anifantis. "Three-dimensional finite element modeling for post-buckling analysis of cracked columns." International Journal of Structural Integrity 7, no. 3 (June 13, 2016): 397–411. http://dx.doi.org/10.1108/ijsi-01-2015-0003.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper is to investigate the effect of crack surfaces contact on the post-buckling behavior of a slender column with a non-propagating crack. Design/methodology/approach – In this paper a 3D finite element model has been implemented to study the post-buckling behavior of a slender column with a non-propagating crack. According to this model, the column is discretized into three-dimensional solid elements. Contact conditions are considered between the crack surfaces. The non-linear equations for this model are solved using an incremental-iterative procedure, and the equilibrium path of the cracked column is extracted. Findings – Load-displacement curves are presented for a cantilever column with a transverse surface crack of either uniform or non-uniform depth across the column cross-section. For both crack shapes, the load-displacement curves are presented for various values of crack depth and position. The results of this study are in good agreement with the results available in the literature. Comparisons with the results of the always-open crack were performed. The post-buckling behavior of a column with a uniform depth crack is more sensitive to variations in crack depth and position than the post-buckling behavior of a column with a non-uniform depth crack. Originality/value – A 3D finite element approach for the post-buckling behavior of a transversely cracked column including contact between crack surfaces.
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Wan, Jia, Qing Fang Niu, Guan Feng Qiao, and Tie Ying Li. "Finite Element Analysis of Chinese Traditional Hall-Style Timber Structure." Advanced Materials Research 1008-1009 (August 2014): 1201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.1201.
Повний текст джерелаАнотація:
This paper uses general finite element software Abaqus to simulate three Chinese traditional hall-style structures recorded in the book <<Yingzao Fashi>>. With Abaqus having an advantage in dealing with contact problems, three hall-style timber structure finite element analysis models have been established within the 3D solid element which is used to model beams, columns, brackets and other structural members in the modeling. Contact pairs also have been used to simulate the interaction between the structure members like beam-column contact pair, column-foot foundation contact pair and dougong-bracket beam contact pair and so on. In the modeling process, some simplifying assumptions have been used for many complex structural members and interactions between them being used in Chinese hall-style structure. The model was finally tested by gravity load and vertical load.
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Wang, Xian Zhi. "Study on Efficiency Factor of Bearing Capacity of Multi-Element Composite Foundation of Concrete Column and Lime Column." Advanced Materials Research 255-260 (May 2011): 178–82. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.178.
Повний текст джерелаАнотація:
Based on the model tests and the results of theoretical research, considered elasto-plasticity of the soil and highly nonlinear behavior of contact with columns and soil, more reasonable numerical model on multi-element composite foundation of concrete column and lime column was built. By changing the design parameters (the diameter of concrete column, the diameter of lime column, the length of lime column, cushion thickness), efficiency factors of bearing capacity of multi-element composite foundation on concrete column and lime column were to play a more systematic study. Some conclusions were drawn in favor of engineering design and theoretical study of multi-element composite foundation of concrete column and lime column.
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Yue, Qing Xia, and Xin Zhang. "Finite Element Analysis on Mechanical Behavior of Column Underpinning Joints for Building Moving." Advanced Materials Research 255-260 (May 2011): 1974–78. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1974.
Повний текст джерелаАнотація:
The building moving has more than 100 years’ history. In the building moving, the design of the underpinning joints is one of the key problems. As to the frame structure, the most widely used method is the double beam underpinning system. Our research group has conduct 16 underpinning joints tests considering the different influential factors to study the mechanical performance of it. This paper first introduces the experiment briefly. And then make finite element analysis on the mechanical behavior of the column underpinning joints using the software ABAQUS as the platform. In the finite element analysis, the solid element is adopted and the master-slave contact surface is used to simulate the interaction between the column and the underpinning beams. The results show that the failure of the moving-beam is ahead of the coupling-beam and the bending-shear failure occurred in the moving-beam. As to the interface between the column and the beam, the lower part of the contact failed and the gaps can be seen. From the analysis results, the contact stress on the column is not uniformly distributed and larger in the upper part of the contact surface which is accord to the test results.
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Cui, Zhao Xia, Yu Peng Guo, Zhi Jun Zhang, Yong Zhi Gong, and Shao Hua Qian. "Optimization Design of Bolted Connections Based on Contact Stress." Advanced Materials Research 694-697 (May 2013): 211–15. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.211.
Повний текст джерелаАнотація:
In a sling and hoisting structure consists of seamless steel tubes as hoisting column, bolts and connectors, all the weights are supported by bolted joints. For the bolt joint is located near the end of the hollow column, the position of the holes in sling column have important influence on the loading ability of the structure. In order to study the reliability of the sling structure, the contact stresses between bolts and its connectors are calculated theoretically and by using FEM (finite element method), and the optimum position of the holes are determined further.
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Zheng,, Y., Y. Rong, and, and Z. Hou. "A Finite Element Analysis For Stiffness of Fixture Units." Journal of Manufacturing Science and Engineering 127, no. 2 (April 25, 2005): 429–32. http://dx.doi.org/10.1115/1.1871183.
Повний текст джерелаАнотація:
This paper presents a systematic finite element model to predict the fixture unit stiffness by introducing nonlinear contact elements on the contact surface between fixture components. The contact element includes three independent springs: two in tangential directions and one in the normal direction of the contact surface. Strong nonlinearity is caused by possible separation and sliding between two fixture components. The problem is formulated by the penalty function method and is solved by the Newton-Raphson procedure. The model was validated by two cases of analysis of a linear cantilever beam and a simple fixture unit with two components. The results are in agreement with the corresponding analytical solution of beams and the previous experimental results for fixture in the literature.
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Chen, Lan Xiang, De Shen Zhao, and Lei Liu. "Finite Element Analysis’s Discussion of Steel-Concrete." Advanced Materials Research 1089 (January 2015): 299–302. http://dx.doi.org/10.4028/www.scientific.net/amr.1089.299.
Повний текст джерелаАнотація:
To analyze the mechanical properties of steel tube filled with steel-reinforced concrete(STSRC), the mechanical models and some related problems of STSRC under different loading ways are proposed for the analysis on the base of finite element software: the concrete plastic damage constitutive model, the contact between steel and the treatment of boundary condition, etc. There are three types of specimen for analysis: short column, long column and pure bending beam. The results indicate that the mechanical models and the relevant technical analysis of STSRC are reasonable, and are beneficial to convergence. The discussed methods can provide a reference for the scholars to study on other composite steel-concrete structures.
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Kostikov, Andrii O., and Serhii A. Palkov. "Contact Deformation of the Pipeline Sealing Unit." Journal of Mechanical Engineering 23, no. 4 (December 30, 2020): 52–62. http://dx.doi.org/10.15407/pmach2020.04.052.
Повний текст джерелаАнотація:
The features of the turbine steam line sealing unit stress-strain state are examined on the basis of the usage of a three-dimensional design model of the construction and contacting surfaces. The considered unit consists of the pipeline, a crimp casing consisting of two halves with an outlet in one of them, and a gasket. A mathematical model that takes into account the mechanical loads caused both by the internal steam pressure on the steam line wall and by the casing fasteners tightening has been formed. This model also includes contact interaction in the sealing unit on the contact surface of the pipeline, the upper and lower halves of the casing. This contact problem solving method, based on the application of the finite element method, is proposed. The finite element model is based on twenty-unit three-dimensional finite elements with three degrees of freedom at each unit. Eight-unit contact finite elements were used to describe contact and sliding between surfaces. Contact conditions are taken into account with the penalty method usage. The verification of the model and the software that implements the proposed method is carried out by comparing the calculation results and experimental data obtained on the physical model of the pipeline. The physical model was made from a low-modulus material with full geometric similarity and the same ratio of the elastic moduli of materials as in a real object. The stress-strain state of the sealing unit of a real pipeline in a three-dimensional setting was determined and the most stressed zones in the unit, which require increased attention during the design and operation of pipelines and their connections, were identified. The developed approach and software make it possible to determine the contact pressure for the horizontal joint flanges of highly stressed cylinder bodies of powerful steam turbines, which helps to avoid a large number of expensive experimental studies.
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Voinov, Nikolai A., Anastasiya V. Bogatkova, and Denis A. Zemtsov. "Intensification of Heat and Mass Transfer in a Diabatic Column with Vortex Trays." ChemEngineering 6, no. 2 (April 12, 2022): 29. http://dx.doi.org/10.3390/chemengineering6020029.
Повний текст джерелаАнотація:
We used vortex contact devices that we developed and investigated to make a new design of an alcohol diabatic distillation column with heat exchange pipes (as the reflux condenser) passing through concentrating section trays. In the column, ascending vapors partially condensed on the surface of vertically installed heat exchange tubes, forming a reflux. The reflux was then mixed with the draining liquid flow in the vortex contact devices placed on the trays. Heat was removed from the column through the boiling of the draining water film along the inner surface of the heat exchange pipes. We compared both diabatic and adiabatic columns fitted with the developed vortex contact devices on the trays. The proposed innovative contact system allows increasing productivity, reducing column dimensions and steam- and heat-transfer medium consumption, and increasing separation efficiency. Dependences for calculating the gas content, hydraulic resistance, and interphase surface required for designing the vortex contact devices of the proposed unit trays are presented.
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Shahu, J. T., and Y. R. Reddy. "Estimating long-term settlement of floating stone column groups." Canadian Geotechnical Journal 51, no. 7 (July 2014): 770–81. http://dx.doi.org/10.1139/cgj-2012-0477.
Повний текст джерелаАнотація:
Design charts for estimating long-term drained settlement of floating stone column group foundations are presented based on three-dimensional, elastoplastic, finite element analyses. In the analyses, the soft soil behavior is represented by the modified Cam-clay model while the stone column and mat are represented by the Mohr–Coulomb model. The finite element predictions are calibrated against model test results. A detailed parametric study of prototype stone column group foundations of various configurations is carried out to evaluate the relative importance of various foundation parameters on the group response. Next, finite element analyses of corresponding unit cells and single columns are performed. Reasonable correlations of load responses are found between single column and group behavior. Group and single column responses are then used to investigate Sg/S1 relationship with different foundation parameters, where Sg and S1 represent the settlement of the group and single column, respectively.
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Yang and Li. "Development of a Refined Analysis Method for Earthquake-Induced Pounding between Adjacent RC Frame Structures." Sustainability 11, no. 18 (September 9, 2019): 4928. http://dx.doi.org/10.3390/su11184928.
Повний текст джерелаАнотація:
Pounding of two adjacent structures is one of the factors that cause damage and hinder sustainable use of reinforced concrete (RC) frame structures under strong ground motion excitations. This study developed a pounding analysis method with a refined beam-column element in order to solve the pounding problem between two RC frame structures. The analysis method combines the fiber beam-column element model with the element sections discretized into concrete and longitudinal rebar fibers, the Hertz-damp contact element model to describe the pounding between beam-column elements, and the method to integrate the pounding force into the system dynamic equilibrium equation. The pounding can be considered either at the level between the story slab to slab or at the level between story slab to mid-column. The application of the proposed method in pounding analyses to provide a rational seismic separation gap between two adjacent RC frame structures is finally conducted to increase their safety and sustainability under strong earthquakes.
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Li, Hai Ning, Dan Li, and Xin Xin. "The Finite Element Analysis of Lei-Ring Applied to Upright Column for Hydraulic Support." Applied Mechanics and Materials 635-637 (September 2014): 541–44. http://dx.doi.org/10.4028/www.scientific.net/amm.635-637.541.
Повний текст джерелаАнотація:
Abstract:In this paper ,the finite element model of the lei-ring was established in ANSYS software,the sealing performance of hydraulic support column piston was analyzed.Also,the numerical simulation analysis was made of the impact of column working pressure on the sealing performance,and a series of the integrated equivalent stress and contact pressure images of sealing ring when working were got. From those images,the location most prone to failure can be concluded.All of work can provide a theoretical reference for the design and use of drum sealing ring used on hydraulic support upright column.
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Kapustina, Natalia, Vladimir Malygin, Vladimir Melekhov, and Vladimir Slutskov. "Modeling of Discrete Contacts for the Thermodynamic Element System of a Modular Wood-Milling Cutter." Lesnoy Zhurnal (Forestry Journal), no. 4 (July 21, 2021): 162–72. http://dx.doi.org/10.37482/0536-1036-2021-4-162-172.
Повний текст джерелаАнотація:
Operational capability of a modular wood-cutting tool depends, besides many factors, on the design features of cutting element fastening unit. There are no clear and precise methods that explain major factors influencing tool durability for selecting the design of the modular wood-cutting tool, which would meet production requirements. Thermodynamics modeling under contact interaction of elements enables to choose a design for effective application and increases the tool efficient life. The research purpose is modeling of thermodynamic processes in the cutter element fastening unit in the wood-cutting tool body in order to optimize the design, technological parameters and operating modes of the tool. The research subject is the contact interaction conditions and heat transfer processes between the device elements. The cutting element fastening unit is designed and the model of interaction between the parts of the mechanism of the modular wood-milling tool is developed. Further tasks, namely, development of a model of thermodynamic processes in the cutting element fastening unit, discussion of the results and identifying the recommendations for choosing the design of the modular wood-cutting tool at the design stage were realized in a work that continues the ongoing research. The finite-element model of rough wavy surfaces contact interaction of design elements was developed on the basis of standard design of a shell-type plain woodmilling cutter. The analysis concluded that further analytical modeling of contact conditions with existing parameters is possible. The contacting surfaces approach and the radii of single contact areas were determined taking into account the data of design and calculation of wood cutting forces. These results will be used next in modeling of thermodynamic processes. Methodology and research methods comprise theoretical study and mathematical modeling, including finite-element analysis. The models developed are possible to be used in the creation of a complex durability model of the wood-cutting tool with regard to other factors. The main result of this research stage is obtaining the model of contact conditions and initial data for further modeling of thermodynamic processes in the knife fastening unit in the milling body to predict its thermal condition.
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Masud, Mahadi, Hongbing Chen, Jiaji Wang, Jamshaid Sawab, Y. L. Mo, and Thomas T. C. Hsu. "High-fidelity finite element simulation of non-contact splices in column-drilled shaft connections." Engineering Structures 239 (July 2021): 112186. http://dx.doi.org/10.1016/j.engstruct.2021.112186.
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Wang, H. L., S. W. Liu, and Z. Zhang. "Seismic Performance and Effects of Different Joint Shapes for Unbonded Precast Segmental Bridge Columns." Journal of Mechanics 32, no. 4 (April 14, 2016): 427–33. http://dx.doi.org/10.1017/jmech.2016.22.
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AbstractTo study the seismic performance and the effects of different joint shapes for unbonded precast segmental bridge columns under low-reversed cyclic loading, two 3-D finite element (FE) models respectively using plane-contact joints and shear resistant joints were established. In the FE models, the mechanical behaviors of concrete and tendons were respectively described by the damage-plastic model and the bilinear model, and the contact criteria was based on Coulomb's Friction. The results of nonlinear time history analysis showed that the deformation of the columns was mainly composed of alternately open-closed joints, and the failure of the column was mainly caused by concrete crush on the bottom segment. Compared with two model's hysteresis loop, backbone curve, ductility and residual deformation, it was found that the column with shear resistant joints had longer stable period of strength, better ductility, and smaller residual displacement than the column with plane-contact joints, so it had better seismic performance.
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Sun, Chun Hua, and Guang Qing Shang. "Effect of Traffic Flow on Characteristics of Piezoelectric Harvesting Unit." Applied Mechanics and Materials 672-674 (October 2014): 902–5. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.902.
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To protect dwindling coal and oil resources and open up a new way of renewable green energy, the technology of piezoelectric harvesting from pavement is proposed. Effect of traffic flow, including contact pressure and speed of a vehicle, on characteristics of a piezoelectric harvesting unit is discussed with the finite element method. Results show that the harvested electric power is approximately linear with the contact pressure and a vehicle’s speed. The contact pressure takes more effect on the harvested electric power and stress on pavement than the vehicle’s speed. A PHU of 280*280*20mm can harvest about 10mJ electric power when the contact pressure is 0.85MPa. That shows that application of the piezoelectric harvesting unit has very nice optimistic prospects.
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Zhao, Jing, Edwin A. H. Vollebregt, and Cornelis W. Oosterlee. "EXTENDING THE BEM FOR ELASTIC CONTACT PROBLEMS BEYOND THE HALF-SPACE APPROACH." Mathematical Modelling and Analysis 21, no. 1 (January 26, 2016): 119–41. http://dx.doi.org/10.3846/13926292.2016.1138418.
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The boundary element method (BEM) is widely used in fast numerical solvers for concentrated elastic contact problems arising from the wheel-rail contact in the railway industry. In this paper we extend the range of applicability of BEM by computing the influence coefficients (ICs) numerically. These ICs represent the Green’s function of the problem, i.e. the surface deformation due to unit loads. They are not analytically available when the half-space is invalid, for instance in conformal contact. An elastic model is proposed to compute these ICs numerically, by the finite element method (FEM). We present a detailed investigation to find proper strategies of FEM meshing and element types, considering accuracy and computational cost. Moreover, the effects of computed ICs to contact solutions are examined for a Cattaneo shift contact problem. The work in this paper provides a guidance to study fast solvers for the conformal contact.
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Li, Guo Chang, Chen Fang, and Hong Ping Yu. "Finite Analysis on Performance of Joint between Gangue Concrete Filled Steel Tubular Column with through Rebar and Gangue Concrete Beam under the Monotonic Loading." Applied Mechanics and Materials 204-208 (October 2012): 3724–30. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3724.
Повний текст джерелаАнотація:
In order to study the performance of the joint between gangue concrete filled steel tubular column with through rebar and gangue concrete beam under the monotonic loading, element analysis model, which is taken into consideration the material nonlinearity, the geometrical nonlinearity and the contact nonlinearity, is established by finite element analysis software ABAQUS. The results show the force transferring mechanism, the stress distribution, the failure model and the load-displacement curve of the joint under the monotonic loading. It indicates in this paper that the joint between gangue concrete filled steel tubular column with through rebar and gangue concrete beam has such numerous advantages as high bearing capacity, large stiffness and good performance. Meanwhile, the paper provides the calculation evidences to analyze the composite construction of gangue concrete filled steel tubular column and the results can be used to make the analysis on the practical structures.
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Cao, Sheng Yong, Liang Xuan, and Ying Shi Sun. "Study on Failure Trend of Double Column Deflection Machine Structure on Basis of Static Strength Analysis." Applied Mechanics and Materials 351-352 (August 2013): 964–68. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.964.
Повний текст джерелаАнотація:
To ensure the safe use of double column deflection machine for processing and manufacturing railway vehicles. This paper analyzes the use conditions of double column deflection machine, and makes a contact nonlinear finite element analysis on various typical use conditions. The positions of parts subject to danger can be found out through the results of static strength analysis, which finds out the weaknesses and prejudges the failure trend of parts, and which provides guidance for prejudging the faults in actual production and can prevent occurrence of accidents.
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Zhu, Jia Ning, Ke Jia Yang, Xiao Wen Li, and Rui Wen Li. "Finite Element Analysis on Crack Resistance Behavior of the Abnormal Joint of SRC Column and RC Beam." Applied Mechanics and Materials 351-352 (August 2013): 61–66. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.61.
Повний текст джерелаАнотація:
Based on the test of abnormal exterior joints of Steel Reinforced Concrete (SRC) column and Reinforced Concrete (RC) beam, the paper analyzed the influence on crack resistance behavior by ABAQUS, of the eccentricity of column section, the steel ratio of the joints zone, the concrete strength and the axial compression ratio and so on. The study indicates that the anti-crack capacity of the joints mainly depends on “the minor joint zone”. Based on the computing unit of minor joint core zone, the calculating formula of anti-crack capacity of the joints is deduced.
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Seneviratne, L. D., S. W. E. Earles, and D. N. Fenner. "Analysis of a Four-Bar Mechanism with a Radially Compliant Clearance Joint." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 210, no. 3 (May 1996): 215–23. http://dx.doi.org/10.1243/pime_proc_1996_210_191_02.
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Clearance joints in high-speed mechanisms can suffer from contact loss, leading to noise generation and joint deterioration. To predict the onset of contact loss detailed modelling of the joint is required. In this paper a clearance joint is modelled using a combined massless link and spring-damper unit, where the bearing stiffness (spring element) is estimated from a three-dimensional finite element analysis. The combined model is shown to exhibit chaotic behaviour just prior to contact loss and the predictions correlate well with experimental results. The bearing stiffness and damping are shown to have a significant effect on the behaviour of the joint, including the occurrence of chaos and the extent of contact loss regions.
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Li, Ri Liang, Ya Feng Xu, and Shou Yan Bai. "The Element Analysis on Hysteretic Property of Cross Steel Reinforced Concrete Special-Shaped Column in Different Rates of Steel Bone." Applied Mechanics and Materials 351-352 (August 2013): 679–82. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.679.
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In this paper, we study the effect of rate of steel bone for the hysteretic property of cross steel reinforced concrete special-shaped column in the same horizontal cyclic load when they have the same axial compression ratio. We use the finite element analysis software ABAQUS to get the deformation pattern by establishing models of column, choosing the constitutive relation reasonably and determining the type of unit. We apply the data of simulation to draw the hysteretic curve and the skeleton curve, and then we analyze the hysteretic property by using the curve and the data. By contrast, it can be seen that the hysteretic property of column enhance with the increasing of rate of steel bone, and the ultimate bearing capacity of column also enhance with the increasing of rate of steel bone.
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Cao, Sheng Yong, Bao Hua Zhang, and Ying Shi Sun. "Study on Failure Trend of Double Column Tri-Axis Deflection Machine Structure on Basis of Static Strength Analysis." Applied Mechanics and Materials 351-352 (August 2013): 975–79. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.975.
Повний текст джерелаАнотація:
To ensure the safe use of double column tri-axis deflection machine for processing and manufacturing railway vehicles. This paper analyzes the use conditions of double column tri-axis deflection machine, and makes a contact nonlinear finite element analysis on various typical use conditions. The positions of parts subject to danger can be found out through the results of static strength analysis, which finds out the weaknesses and prejudges the failure trend of parts, and which provides guidance for prejudging the faults in actual production and can prevent occurrence of accidents.
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Liu, Hong Bo, Long Jun Xu, Shuang Li, and Yong Song Shao. "Finite Element Fracture Mechanics Study of Web Connections with Tapered Beam Flange Plates." Key Engineering Materials 452-453 (November 2010): 473–76. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.473.
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Brittle fracture was identified in many of prequalified weld joints in steel moment frames in the 1994 Nothridge earthquake. Then analyses of response and damage mechanism of beam-to-column connections under seismic load were widely studied in the world, but few people conduct the research on seismic-resistant behavior of beam-to-column web connections. To quantify the variation of stress intensity factor to weld root flaw sizes beam-to-column web connections with tapered beam flange plates, detailed 3D finite element analyses is used to study fracture toughness requirements in beam-to-column web connections, considering the large deformation, large strain, bolts pretension, bolt contact-slide, as well as material harden and soften. Fracture toughness demands are evaluated in terms of the mode I stress intensity factor. The stress intensity factor is calculated through a J-integral approach. The fracture toughness demands are studied for the flaw on the top of the beam flange and the bottom surface, respectively. Results indicate that the likelihood of top flange fractures is smaller than that of bottom flange fracture. Stress intensity factor is not uniform and is largest in the edge of beam flange. The fracture toughness in the edge of beam flange for web connections with step beam flange plates is 15% less than that for tapered beam flange plates.
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Gaber, Maryam, Anuar Kasa, Norinah Abdul Rahman, and Jamal Alsharef. "Comparison between unit cell and plane strain models of stone column ground improvement." International Journal of Engineering & Technology 7, no. 2 (March 12, 2018): 263. http://dx.doi.org/10.14419/ijet.v7i2.8797.
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This article presents a comparative study of the behaviour of clayey soil reinforcements using stone column ground improvement by means of numerical analyses. Two-dimensional finite element analyses with commercially available software, PLAXIS, were performed on end-bearing stone columns using 15-noded triangular elements to investigate the impact of the modelling type on the stress concentration ratio and failure mechanism of an improved foundation system. Consolidation analyses were conducted throughout the study using Mohr-Coulomb’s criterion. The computed values of the stress concentration ratios were compared for different key parameters, including the diameters of stone columns, c/c spacing of columns, friction angle of stone column material, and undrained cohesion of soft soil. The major conclusions of this study were that the stone column in the unit cell model shared between 2.5 to 3.14 times more loads than the surrounding soil, whilst in the plane strain model it shared between 1.7 to 2.9 times more loads. The use of plane strain approach to model the stone column gave a more comprehensive representation of the stress distribution and load transfer between the soil and columns, in addition to being a better method than the unit cell concept to evaluate the failure mode in this system.
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Stover, R. J., H. H. Mabie, and M. J. Furey. "A Finite Element Investigation of a Bearing/Cartridge Interface for a Fretting Corrosion Study." Journal of Tribology 107, no. 2 (April 1, 1985): 157–63. http://dx.doi.org/10.1115/1.3261011.
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The bearing/cartridge interfaces of a Ship Service Motor Generator Set (SSMG) were modeled by using finite element technology. The purpose of this analytical study was to verify the results of earlier experimental tests made on an actual SSMG unit. This research is part of a larger research project to examine the important parameters influencing the fretting of rolling element bearings. Models for the bearings at both ends of the unit were developed, and loads simulating the ball pass loads were applied to these models; the contact pressures, radial deformations, and relative displacements at the interface were calculated. The resulting data showed the interface conditions to be extremely complex with the contact pressures varying from zero to a maximum of 55.4 MPa (8030 psi) as the balls passed by. The maximum relative displacements occurred in the tangential direction (2.44 μm) and were independent of the axial boundary conditions.
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Lexian, H., and B. M. Dariani. "An analytical contact model for finite element analysis of tube spinning process." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 222, no. 11 (November 1, 2008): 1375–85. http://dx.doi.org/10.1243/09544054jem1202.
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This work presents an analytical contact model for non-linear dynamic finite element (FE) analysis of the tube spinning process that is based on the Belytschko—Lin—Tsay shell element with an explicit time integration scheme. A brief description of the FE formulation of a first-order shear deformation shell element as well as internal forces calculation, nodal mass calculation, and prediction of stable time step are presented. An analytical contact model is developed for a general roller. Analytical equations of the roller surfaces, interpenetration, and unit vector normal to the contact surface are determined. Contact forces are approximated by a penalty method with a suitable estimation of the penalty coefficient. An explicit FE code, using the developed analytical contact model, is designed and its implementation algorithm is described in detail. The dome forming process of a seamless pressure vessel is simulated using this code, in which the contact analysis is performed robustly, which saves significant amounts of computer time. A steel alloy DIN 1.7225 seamless pressure vessel, which was formed by a hot-spinning process, is cut longitudinally and its profile is measured. A comparison between the longitudinal cross-section profiles calculated by FE analysis and that obtained from experiment shows a good agreement.
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Liu, Jen-Yu, and Hong-Sen Yan. "Surface Geometry of Variable Pitch Cylindrical Cams with Conical Meshing Elements." Journal of Mechanical Design 116, no. 3 (September 1, 1994): 862–66. http://dx.doi.org/10.1115/1.2919461.
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This paper presents mathematical expressions for the surface geometry of variable pitch cylindrical cams with four conical meshing elements based on the theory of conjugate surfaces. The unit normal of the element is derived, with given surface geometry of the meshing element, by differential geometry. The contact lines of the conjugate surface are defined according to the equation of meshing and the specified input-output relation. By the coordinate transformation of contact lines, we have the complete profile of the variable pitch cylindrical cam. The results of this work are instrumental in computer-aided manufacturing of variable pitch cylindrical cams for industrial applications.
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Zhao, Xin Hui, and Jin Li. "Research of Mechanical Property on High-Rise Building Shear Wall-Influence of Border Concealed Column Toward Shear Wall Stiffness." Advanced Materials Research 243-249 (May 2011): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.274.
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This article is probed into on the issue that the influence of border concealed column toward shear wall stiffness. Charge example indicates finite element that this text set up calculate model is acceptable. It is used the finite element method basic theory to compile finite element analysis procedure with four points rectangles unit to solve this problem. It can calculate the shear wall with concealed column’s displacement under the wind load to check the result it whether can be satisfied the design request. Using this procedure, this article carries on the finite element modeling analysis on a ten-floor building shear wall structure system. The procedure’s result and the software of ANSYS’s result tallies well, and it also be compared with the simplification computation’s result.
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Liu, Jian, Guang En Zhou, and Deng Feng Peng. "Study on Seismic Behavior of Double Web-Angle and Top-Seat-Angle Beam-to-Column Connections." Applied Mechanics and Materials 501-504 (January 2014): 1551–55. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1551.
Повний текст джерелаАнотація:
In order to study seismic behavior of double web-angle and top-seat-Angle connections, finite element methods, which included material, geometric and contact nonlinearity, were used to the model under cyclic loading. The effects of the angle length, the angle thickness, the bolt diameter and grade on strength, and the gauge distance from the edge of the angle to the center of bolt line on strength and hysteretic behavior of connections were studied. Finite element results reveal that the hysteretic behavior, initial stiffness and load bearing capacity are significantly affected by the gauge distance from the edge of the angle to the center of bolt line, the angle length, the angle thickness and the bolt diameter and grade.
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Xu, Shan Shan, and Wei Wei Li. "Application Analysis of Finite Element Method in the Calculation of Foundation Pit Excavation." Advanced Materials Research 898 (February 2014): 395–98. http://dx.doi.org/10.4028/www.scientific.net/amr.898.395.
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This paper introduces the finite element method theory of foundation pit excavation, on the basis of summarizing the past experience, combined with the mechanical property of engineered soil, by using a variety of contact relation provided by the finite element software, select the appropriate unit to simulate the foundation pit excavation model scientific and reasonable. It has a very important guiding significance in practical engineering.
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Serikov, Viktor, David Vlasov, and Ludmila Goreva. "Active Power Losses in Pressure Rings for Contact Shoes of Ore-Thermal Furnace." Applied Mechanics and Materials 698 (December 2014): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amm.698.57.
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Results of electromagnetic problem solution for three-phase electrodes system in ore-thermal furnace for electrodes equivalent electric circuit parameters calculation made by using 3D-models in numerical finite element method program package ANSYS are presented. Contact shoes pressure rings and heat shield of energy feeding unit are taken into account.
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Krolo, Paulina, Davor Grandić, and Mladen Bulić. "The Guidelines for Modelling the Preloading Bolts in the Structural Connection Using Finite Element Methods." Journal of Computational Engineering 2016 (June 15, 2016): 1–8. http://dx.doi.org/10.1155/2016/4724312.
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The aim of this paper is the development of the two different numerical techniques for the preloading of bolts by the finite element method using the software Abaqus Standard. Furthermore, this paper gave detailed guidelines for modelling contact, method for solving the numerical error problems such as numerical singularity error and negative eigenvalues due to rigid body motion or the problem of the extensive elongation of bolts after pretension which is occurring during the analysis. The behaviour of bolted joints depending on the two different approaches of pretension was shown on the example of an extended end-plate bolted beam-to-column connection under the monotonic loading. The behaviour of beam-to-column connection was shown in the form and moment-rotation (M-ϕ) curves and validated by experimental test. Advantages and disadvantages of pretension techniques, as well as the speed of numerical models, were also presented in this paper.
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Wang, Sentong, Kazunori Hase, and Susumu Ota. "Development of a Lower Limb Finite Element Musculoskeletal Gait Simulation Framework Driven Solely by Inertial Measurement Unit Sensors." Biomechanics 1, no. 3 (October 18, 2021): 293–306. http://dx.doi.org/10.3390/biomechanics1030025.
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Finite element musculoskeletal (FEMS) approaches using concurrent musculoskeletal and finite element models driven by motion data such as marker-based motion trajectory can provide insight into the interactions between the knee joint secondary kinematics, contact mechanics, and muscle forces in subject-specific biomechanical investigations. However, these data-driven FEMS systems have a major disadvantage that makes them challenging to apply in clinical environments, i.e., they require expensive and inconvenient equipment for data acquisition. In this study, we developed an FEMS model of the lower limb driven solely by inertial measurement unit sensors that include the tissue geometries of the entire knee joint, and that combine modeling of 16 muscles into a single framework. The model requires only the angular velocities and accelerations measured by the sensors as input. The target outputs (knee contact mechanics, secondary kinematics, and muscle forces) are predicted from the convergence results of iterative calculations of muscle force optimization and knee contact mechanics. To evaluate its accuracy, the model was compared with in vivo experimental data during gait. The maximum contact pressure (11.3 MPa) occurred on the medial side of the cartilage at the maximum loading response. The developed framework combines measurement convenience and accurate modeling, and shows promise for clinical applications aimed at understanding subject-specific biomechanics.
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Moiseev, Viktor, Eugenia Manoilo, Oleg Khukhryanskiy, and Kalif Repko. "Experimental research of mass transfer in a stabilized foam layer." ScienceRise, no. 5 (October 29, 2021): 14–22. http://dx.doi.org/10.21303/2313-8416.2021.002123.
Повний текст джерелаАнотація:
The object of research: mass transfer processes on a combined contact element in a column apparatus.
Investigated problem: determination of the regularities of process parameters in the processing of gas-liquid systems in a foam layer, as well as to interpret the obtained experimental data. The problem of processing industrial gas flows is solved by conducting the process in an intensive mode.
The main scientific results: as a result of the study, the regularities of ammonia absorption were revealed depending on the main parameters of the experiment: gas velocity in the column cross-section, ammonia concentration, free cross-section of the combined contact element, and liquid loads. The process of mass transfer in the gas phase is significantly influenced by hydrodynamic parameters – the gas velocity in the apparatus and the specific load on the liquid, which indirectly affect the height of the liquid layer on the plate and the gas content of the layer.
The area of practical use of the research results: sorption processes for processing gases and liquids in technological processes, absorption of harmful substances in the treatment of gas emissions.
Innovative technological product: new block poppet-nozzle contact device that operates in a stabilized hydrodynamic mode; new ball-shaped weighted nozzle for three-phase foam layer.
Scope of application the innovative technological product: technological processes in the treatment of gas emissions or technological gases.
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Sun, Jian-Qiang, Xi-An Li, Mei-Le Bi, Kai-Xuan Zhang, and Jing Zhang. "Investigation on Creep Behavior of Aggregates of Loess by a Discrete Element Method." Processes 10, no. 4 (April 18, 2022): 795. http://dx.doi.org/10.3390/pr10040795.
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In loess the aggregate is the basic structural unit, and its stability is an important factor affecting the composition, water stability and strength of loess. However, due to the difficulty of sample preparation, few scholars have done independent research on it. In this manuscript, a numerical model of aggregate is constructed by the discrete element method. Under the continuous action of certain stress, the uninterrupted development process of sample deformation with time was observed, that is, the creep of aggregate structures. The results show that the creep of aggregates is closely related to the relative movement, rotation and rearrangement of internal structural elements, and the most intuitive mesoscopic evolution of the adjustment process of structural elements is the change of contact number, namely the coordination number. The microscopic parameters and evolutionary characteristics of fabric can reveal the microscopic mechanism behind the macroscopic creep phenomenon. With the creep process, the creep stress is gradually borne by the normal contact force rather than the tangential contact force and has anisotropic characteristics. As a result of creep, the contact points of particles increase, and the interaction between aggregates changes from point contact to overlap contact. The constraint between aggregates increases, and the skeleton tends to be a more stable structure, which can bear a larger load.
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Yang, Ya Luo, Ya Yu Huang, and Wu Hao. "Research of Single Granule and Granule Group Motion Model by DEM." Applied Mechanics and Materials 84-85 (August 2011): 125–29. http://dx.doi.org/10.4028/www.scientific.net/amm.84-85.125.
Повний текст джерелаАнотація:
Distinct element method (DEM) is based on Newton's second law of motion and the basic law of particles between elements colliding. It's an effective numerical method which widely used in many engineering fields by using dynamic relaxation method on Iterative calculation. By comparing the linear contact model and nonlinear contact model of DEM, Cundall spring-damp-sliding contact model had been selected as our major studying model. Then the coordinate of the contact point, “composite quantity” of each contact unit and the relative velocity between units in this system had been calculated. And finally the numerical simulation on the motion state of single granule and granule group had be done.
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Konkong, Nirut, and Kitjapat Phuvoravan. "An Analytical Method for Determining the Load Distribution of Single-Column Multibolt Connection." Advances in Civil Engineering 2017 (2017): 1–19. http://dx.doi.org/10.1155/2017/1912724.
Повний текст джерелаАнотація:
The purpose of this research was to investigate the effect of geometric variables on the bolt load distributions of a cold-formed steel bolt connection. The study was conducted using an experimental test, finite element analysis, and an analytical method. The experimental study was performed using single-lap shear testing of a concentrically loaded bolt connection fabricated from G550 cold-formed steel. Finite element analysis with shell elements was used to model the cold-formed steel plate while solid elements were used to model the bolt fastener for the purpose of studying the structural behavior of the bolt connections. Material nonlinearities, contact problems, and a geometric nonlinearity procedure were used to predict the failure behavior of the bolt connections. The analytical method was generated using the spring model. The bolt-plate interaction stiffness was newly proposed which was verified by the experiment and finite element model. It was applied to examine the effect of geometric variables on the single-column multibolt connection. The effects were studied of varying bolt diameter, plate thickness, and the plate thickness ratio (t2/t1) on the bolt load distribution. The results of the parametric study showed that thet2/t1ratio controlled the efficiency of the bolt load distribution more than the other parameters studied.
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Taufik, Syaril, Shahrizan bin Baharom, and Robert Y. Xiao. "Predicted Behaviour of Partially Restrained Connection with Cold Formed High Strength Steel by 3D Finite Element Modelling." Advanced Materials Research 250-253 (May 2011): 1734–43. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1734.
Повний текст джерелаАнотація:
Thispaper investigates the behavior prediction of partially restrained (PR) connection with high strength steel bythree-dimensional nonlinear finite-element (FE) analyses. The connectionmodel is such that angle cleats are represented by radiuses corner section shell elements. The full interaction between angle and beam and/or column is simulated by contact element. The analysis results of the moment- rotation relationship and behaviour characteristic of the connection with high strength steel are compared and discussed. It is found that contact element and strength enhancement of the corner regions employed to the model are very important parameters for accurate prediction of PR connection behaviour with cold-formed high strength steel. The moment capacity prediction of top and seat angle connections based on EC3 has been shown to be reasonable compared with FE modeling. Theproposed connection FE model is capable of predicting the ultimate load capacity and the plastic strain pattern with good accuracy. The model presented gives excellent results for increasing the connection capacity significantly due to employed higher strength steel section.
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Zhu, Jia Ning, Ke Jia Yang, Xiao Wen Li, and Rui Wen Li. "The Anti-Shear Capacity of Abnormal Joint of Steel Reinforced Concrete." Applied Mechanics and Materials 357-360 (August 2013): 863–68. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.863.
Повний текст джерелаАнотація:
The paper presents an test and computational results of finite element studies on the behavior and capacity of abnormal exterior joints of Steel Reinforced Concrete (SRC) column and Reinforced Concrete (RC) beam. The critical parameters influencing Anti-Shear Capacity are analyzed by ABAQUS, such as the eccentricity of column section, the steel ratio of the joint core zone, the concrete strength and the axial compression ratio and so on. As a result, the Anti-Shear capacity of the joints mainly depends on “the minor joint zone”. The calculating formula of Anti-Shear capacity of the joints, with the computing unit of minor joint core zone, is deduces.
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Anand, Praveen, and Ajay Kumar Sinha. "Effect of Reinforced Concrete Jacketing on Axial Load Capacity of Reinforced Concrete Column." Civil Engineering Journal 6, no. 7 (July 1, 2020): 1266–72. http://dx.doi.org/10.28991/cej-2020-03091546.
Повний текст джерелаАнотація:
Whenever a member of a structure becomes structurally deficient, it becomes vulnerable to the existing load and for the additional loads that it may be subjected to in the coming future. Since columns are the most important structural element, the structural retrofit of columns, relative to other structural elements is of prime importance. This study intends to investigate the performance and behaviour of an RC column jacketed with Reinforced Concrete columns under axial loads. The objective of this paper is to find out the efficiency of RC jacket in enhancing the strength of an existing RC column. A mathematical design based upon Indian Standards codes has been designed to identify the behaviour of jacketed RC columns. This has been followed by a finite element based numerical simulation using the same material properties as used in the process of designing. The simulation has been done in ABAQUS software with appropriate contact modelling. The analytical model considers that there is no bond slippage between the existing and new concrete surface i.e. the bond between the existing and new concrete is assumed to be perfect. This perfect bond between the surfaces has been modelled by using appropriate constraints in ABAQUS software. The finite element models show fair agreement with the designed values in terms of ultimate capacity and failure mode. The load bearing capacity enhancement of the RC jacketed column has been found to increase substantially. The enhancement capacity results obtained from the finite element software differs about 16-25% from the design values.
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Yamamoto, K., T. Iwatsubo, Ken-ichi Saitoh, and T. Moriuchi. "Simulation of Water Flow in a Coated Nano Pore by a Molecular Dynamics." Advances in Science and Technology 57 (September 2008): 73–79. http://dx.doi.org/10.4028/www.scientific.net/ast.57.73.
Повний текст джерелаАнотація:
This paper presents on a new damping element called the colloidal damper which is used a principle of surface extension force in nano pore. The direction acting of the surface extension force of water in hydrophobic nano pore is different in pressurization and decompressurization processes [1,2]. This principle is applied to a damping element. The nano pore is constructed by silica gel. A silica gel ball of 100-200 micrometer dia. has many nano pores of 5-20 nanometer dia. in it [3,4]. The coated spherical silica gel and water are inserted in a piston - cylinder unit in order to work as a damper. If compression and decompression forces are added to the piston - cylinder unit (damper), water flows into and moves out the nano pore under balance of pressure. A contact angle of compression formed by the hydrophobic nano pore and water is larger than that of decompression. This difference of the contact angle produces a damping energy. In this paper, behavior of water in the pore of silica gel is investigated using the molecular dynamics. Dissipation energy of the colloidal damper is concerned with the contact angles of water in the pore. So the contact angles are calculated for changing parameters, i.e. size of the pore, length of the hydrophobic material, velocity (pressure) of water flows into the pore. Then these results are compared with the experimental ones.