numerical analysis

Open Access Article

1 - Numerical simulation of multilayer cellular scaffolds with 3D and 1D elements
Hamid Reza khanaki Sadegh Rahmati Mohammad Nikkhoo Mohammad Haghpanahi Javad Akbari

10.30495/admt.2020.1905314.1207

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2 - Fabrication, Testing and Analysis of Composite Lattice Panels Under Three-Point Bending Load
Mahdi Farhadi Ali Davar Mohsen Heydari Beni Jafar Eskandari Jam

10.30486/admt.2021.1908801.1217

Thanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structur More

Thanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structures, honeycomb (core) sandwich panels, and aluminum grid structures. In this paper, a composite lattice panel is first fabricated from glass/epoxy by hand lay-up method using a silicon rubber mold. In this method, a Kagome composite lattice panel with twelve layers of resin-impregnated fibers was fabricated during a continuous process. After fabrication, the test panel was shown under three-point bending and failure modes. Also, a numerical simulation of three-point bending was performed in ABAQUS software. Then, the simulation results were compared with those of the experimental test, indicating a good convergence between the experimental test results and the finite element ones up to the point of failure. Due to changes in directions of force, these structures have a high ability to withstand damage, and therefore, continue to withstand the load after the failure of one or more ribs. Also, there is no sudden and sharp drop in the load-bearing capacity of the structure despite the force being maximized, which can be attributed to the high energy absorption of such structures. Instead, the force decreases slowly with fluctuations, and the structure continues to absorb energy until final failure. Therefore, such lightweight structures can be used in applications where energy absorption is of great importance. Manuscript profile

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3 - Numerical study on nanofluid natural convection in a vacuum tube solar collector with phase change materials
seyed Alireza Nazem Iman Zahmatkesh

As an eternal and widespread energy source, solar energy has a low density while its intensity is changing continuously. Unavailability of the solar energy in nights and the gap between the time of radiation and its consumption are concerned as the main drawbacks of thi More

As an eternal and widespread energy source, solar energy has a low density while its intensity is changing continuously. Unavailability of the solar energy in nights and the gap between the time of radiation and its consumption are concerned as the main drawbacks of this type of energy. In applications such as domestic hot water (DHW), phase change materials (PCMs) can successfully remove this shortcoming due to their high thermal capacity and constant temperature during the phase change process. However, thermal conductivity of water is relatively low which reduces the performance of vacuum tube solar collectors. This properties can be improved substantially with the utilization of nanofluids. This paper presents a numerical study on nanofluid natural convection in a vacuum tube solar collector with phase change materials. The studied nanoparticles include copper oxide, titanium oxide, iron oxide, aluminum oxide, and graphene oxide. The obtained results show that for all of the current nanoparticles, rise in the nanoparticles volume fraction is accompanied by a decrease in the exit temperature of the collector. It is found that the highest temperature belongs to the graphene oxide nanoparticles. Manuscript profile

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4 - Representing a modern method to tunnel stability analysis with introducing a new scheme for Ground Reaction Curve (GRC); case study: Garin dam water Diversion tunnel
S.M Hoseini کاوه Ahangari کامران Goshtasbi

The most important problem in tunneling project about design and performance is selectionsuitable pattern for drilling and support system, in order to stability of rock mass and reductionplasticity zone. Meanwhile determine the amount of tunnel wall deformation prior to More

The most important problem in tunneling project about design and performance is selectionsuitable pattern for drilling and support system, in order to stability of rock mass and reductionplasticity zone. Meanwhile determine the amount of tunnel wall deformation prior to supportinstallation is of great importance. When a tunnel is excavated, there is a certain amount ofdeformation, usually 35-45 percent of the fnal tunnel wall deformation, before the support canbe installed. Determining this deformation can be done using either a) observed feld values, orb) numerically from 3D fnite-element models or symmetrical fnite-element models, or c) byuse of empirical relationships such as those proposed by Panet or Vlachopoulos-Diederichs. Inthis paper, convergence-confnement method is applied to tracing ground characteristic curveusing numerical software models and then stress relaxation is exerted to modal that equivalentwith occurred critical convergence until prior to support installation. In this study, a new chartis introduced which unlike conventional charts, the modulus reduction ﬂow has been used inthat vertical axis. Finally the safety factor of support system has been calculated by three different methods. Manuscript profile

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5 - Estimating the Loss of Life of the Electrical Power Transformer based on TOT and HST
Mohammad Tolou Askari Mobina Afagh

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6 - 3D Analysis of Improved Soft Ground with a Group of Floating of Stone Columns Laid on the Appropriate Bed
Mohammad Shabani Mehdi Hatami Hasan Golmaee Saman Arechi

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7 - Assessment of Soil cohesion of Soils on Tunnel Excavation
Mohammad Azadi

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8 - Soil-Interaction of Intake Pressure Tunnels under Ground Strength Reduction Conditions due to Cracking of the Lining (Case study: Dasht-e-Abbas intake pressure tunnel)
seysd majddin Mir Mohammad Hosseini P Malek Mohammadib M. Asadolahi Pajouhc

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9 - The Stability Assessment of Dasht-e-Abbas Pressure Intake Tunnel Subjected to Ground Strength Reduction-Iran
S. M Mir Mohammad Hosseini P Malek Mohammadi M Kargar

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10 - Buckling of Stiffened Thin Walled Cylindrical Shells due to Global Shear
Mehran seyedRazzaghi F. Karimi

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11 - Numerical Analysis of surface Ozone and its relation to synoptic patterns in Tehran
Ali Afshariazad Bahman Ramezani atoosa bigdeli mohammadreza afshariazad

This research tries to assess the emission and concentration of surface Ozone related to the synoptic weather patterns in general circulation of atmosphere. 2020 – 2021 is the time and Tehran is the place of this research. Based on the defined scenarios, the extre More

This research tries to assess the emission and concentration of surface Ozone related to the synoptic weather patterns in general circulation of atmosphere. 2020 – 2021 is the time and Tehran is the place of this research. Based on the defined scenarios, the extreme emission day, the pure day accompanied with stability and instability of the atmosphere, air pressure in sea level and 500 hpa. Skew-T chart from Mehrabad airport were analyzed. The emission datum was taken from the six stations of the air quality control organization in Tehran. The analysis was done daily and seasonally. The result of the research shows that in 24 hours emissions the most concentration happens in the mid-day and last until 6 in the evening. Among the seasons, summer has the most concentration because of the dominance of high pressure in atmosphere, increase in surface temperature high radiation and wind speed. More than 6 m Manuscript profile

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12 - Numerical Simulation of Homogeneous, Two and Three Lattice Layers Scaffolds with Constant Density
Hamid Khanaki Sadegh Rahmati Mohammad Nikkhoo Mohammad Haghpanahi Javad Akbari

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13 - The Recommend of Filler Metal to Increasing the Corrosion Resistance of Gas Pipeline
Esmaeil Jafari Mohammad Sadegh Karimi

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14 - Investigation of Effective Plastic Strain Heterogeneity and the Effect of Using Interface Sheet in Constrained Groove Pressing of Copper Sheet
Moein Gholami Ali Hasanabadi

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15 - Investigation of the Girth Size and intervals Effect on Lateral Buckling Strength of Built-up Double I & C-Sections Columns
jaber hemayati ahmad rahbar ranji

       Steel composite columns with parallel girth are one of the common types of columns used in steel structures in the country (IRAN). Despite many studies on the behavior of these columns, the impact dimensions and spacing of girth on t More

       Steel composite columns with parallel girth are one of the common types of columns used in steel structures in the country (IRAN). Despite many studies on the behavior of these columns, the impact dimensions and spacing of girth on the buckling load of these columns have been less considered. In addition to resistance criteria, in designing of pressure members, the stability criteria must also be considered. In other words, the pressure members of a structure will be defeated effectively by local buckling before reaching maximum compressive strength or influence of buckling phenomenon. The local buckling is one of the common instability of structural members and is an important factor in design of the Built-up columns, so the buckling phenomenon of these columns must be strongly controlled. In this research, 10 columns by double I sections and 6 columns by double C sections were analyzed by different intervals of girths. All column sections are double IPE140 or UNP140. Dimensions of the girth in double I sections are 100×180 mm, with thickness of 4, 6 and 8 mm, by intervals axes to axes 400, 600 and 800 mm in both side. Dimensions of the girth in double C sections are 100×140 mm, with thickness of 4 and 6 mm, by intervals axes to axes 400, 600 and 800 mm in both side. Finally, the elastic buckling load of these columns was obtained by using the Abacus finite element software and compared with the relationships in the tenth chapter of the National Building Regulations. Manuscript profile

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16 - Numerical Analysis of Post-Tensioned Steel Moment Connections with Top and Seat Angles
rohollah ahmadi jazani peyman Shadman heydari mehdi amrii

To reduce or eliminate residual deformations in the main members of the structures after an earthquake, researchers presented the idea of using self-centering systems. Several types of self-centering systems have been proposed.One of the strategies for created self cent More

To reduce or eliminate residual deformations in the main members of the structures after an earthquake, researchers presented the idea of using self-centering systems. Several types of self-centering systems have been proposed.One of the strategies for created self centering in structures, using post-tensioned(PT) steel moment connections. Until now several types of PT steel connections is provided. In this paper, results of numerical analysis using finite element method in ABAQUS software for five full-scale model of interior PT steel connections with bolted top and seat angles has been studied. The results of numerical analysis in this research demonstrate the beams and columns remain essentially elastic while inelastic deformation of the top and seat angles provided energy dissipation and also using post-tensioning method, increase loading capacity significantly without residual deformation in main members of the connection. In a PT connection, maximum stresses in beam created at the flange of beam and using longer reinforcing plate, cause decrease stresses created in beam and reduce various damage index and risk of brittle fracture in tension angles.Cyclic behavior of numerical model of PT connection with combined axial load and drift demand shows that the axial load reduces bearing capacity of connection. Manuscript profile

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17 - Numerical investigation of the perimeter Wall Behavior under blast Loading with the approach of protecting structures and facilities
yaser moeini ahmad ganjali Mohammad Taji

10.30495/civil.2023.702774

By increasing the risk of explosive terrorist attacks and threats to all types of structures and buildings, a careful study of the behavior of structures under explosive loading is considered as an important matter. A simple method to protect important structures agains More

By increasing the risk of explosive terrorist attacks and threats to all types of structures and buildings, a careful study of the behavior of structures under explosive loading is considered as an important matter. A simple method to protect important structures against explosive loads is to improve the security of the environment by using protective perimeter walls against explosive loading. In this research, the effect of reinforced concrete perimeter walls with and without canopy has been investigated. Different parameters such as the geometrical shape of the perimeter wall, the element removal and degradation rate, wall displacement, the scaled distance change and the explosive mass have been investigated. Finite element software (LS-DYNA (R11.1.0) has been used for modeling. For this purpose, the perimeter walls were designed in three different shapes and conditions. The results indicate that the existence of canopies for the perimeter walls under explosive loading has positive effects, so that the canopied perimeter walls with a canopy angle of 90 degrees compared to other types of wall, at different station distances and in the same conditions, reduce the displacement rate in the protected structure by about 11 percent. Furthermore, the location of perimeter walls and obtaining a safe distance in placing these walls is very effective in enhancing safety and reducing the vulnerability of the facilities and structures protected by these walls. Manuscript profile

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18 - Evaluation of Flexural Performance of Steel I-Beams Prestressed with Unbounded Bar Tendons by Numerical Analysis Method
Afshin Yadegari rasool khodayari mohammad ali lotfollahi Yaghin

The basic purpose of applying the Prestressing technique in steel structures, weight decrease of sections because of is increase their load-carrying capacity that this eventually led to the realization of technical and economic advantages of such structures are. In this More

The basic purpose of applying the Prestressing technique in steel structures, weight decrease of sections because of is increase their load-carrying capacity that this eventually led to the realization of technical and economic advantages of such structures are. In this paper, prestressing method in steel I-beams, as post-tensioning of the external tendons installed in various samples of steel beams, to determine the increase of flexural strength and improve of load capacity, is analysis and evaluation by the finite element software of ABAQUS. Considering the existence of experimental results in this study, and comparison between these results and analysis done for each of the samples, among them a suitable corresponded can be observed and applying the prestressing technique, Flexural behavior of beams in the form of indicators such as stress, strain and displacement bottom flang of the  beem in the mid-span, are all significantly to be improved. Manuscript profile

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