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Buried concrete tanks serve as critical components of public and military infrastructure, where structural damage can trigger severe social, security, and environmental crises. Consequently, designing these tanks to withstand shock loads from explosions is of paramount importance. Additionally, the behavior of layered clay soils under such loading conditions requires detailed examination. This study investigates the influence of burial depth on the performance of concrete tanks subjected to explosive loads in layered clay soils. The analysis was conducted using AUTODYN and FLAC 2D finite element software. Concrete tanks buried at depths of 3, 6, 8, and 10 meters were analyzed under surface explosions generated by 50, 100, and 200 kg of TNT, with defined pressure and distance parameters. The soil properties, structural characteristics, and internal fluid pressure were incorporated into the model. Results indicate that increasing the burial depth significantly reduces the displacement of the tank roof and floor due to the dissipation of explosion energy in the surrounding soil. For instance, with a 50 kg TNT charge, increasing the burial depth from 3 meters to 6, 8, and 10 meters resulted in roof displacement reductions of 54%, 70%, and 78%, respectively. These findings demonstrate the critical role of burial depth in enhancing structural resilience against explosive loads and mitigating damage.
 

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Abstract: The experimental study of structural vibration is often performed to determine the modal parameters of a structure or to verify the theoretical models and predictions. The first phase of this research involved the experimental determination of the modal properties of a rectangular steel tank with different levels of water. The natural frequencies obtained from the experiments were compared to those calculated by the analytical models. In the second phase, a procedure for computing hydrodynamic pressures in rectangular tanks is proposed. This procedure considers the effect of tank wall flexibility in determining the hydrodynamic pressures produced by the impulsive response. Based on a two-dimensional model of the tank wall, a dynamic time-history analysis was carried out. The results were compared with other models based on the current design practice codes and standards, which use a lumped mass approach. The comparison shows that, in most cases, the lumped mass approach overestimates the base shear. The effect of wall flexibility on wall displacements and base shears are also discussed.

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This research deals with configuration design and layout optimization of communication satellite. First, an approach is proposed to design the configuration of GEO satellite. Since propulsion subsystem in GEO satellite is the massive item, it has a significant impact on satellite configuration. Consequently, it is necessary to consider the propulsion subsystem influence on satellite configuration. Then layout design process of the satellite components which is one of the complex problems in engineering is performed. In this paper, in order to optimize the layout design of satellite components, the algorithm which consists of two stages, primary and detail layout, is proposed. In order to express geometric constraints mathematically, the Finite Circle Method (FCM) is used. For The mathematical expression of performance constraints, the distance constrains related to distance relationships between components have been developed. The hybrid optimization method is proposed to optimize layout design which is a combination of Simulated Annealing optimization and Quasi Newton methods. The optimization method validation is applied on simple test problem. Finally, the proposed algorithm for configuration and optimal layout design is implemented on communication satellite. The results show that product of inertial (objective function) are minimized and considered constrains of communication satellite are satisfied.

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Numerical Investigation of the number of baffles effect on the efficiency of primary sedimentation tank in true dimensions.
Settling tanks of wastewater treatment plants are the most important components so that about one-third of the cost of a wastewater treatment plant construction is concerned to these tanks. In addition, the regulations referred to design of settling tanks are not enough. According to these, the adverse factors in settling tanks is very important to design and improve their performance. These factors in primary sedimentation tanks are including circulation zones, the phenomenon of short circuiting and non-uniform flow. One of the most important ways to improve flow conditions and increase the efficiency of settling tanks, is modifying the geometry of the tank through the installation of baffles. In this investigation, the effect of baffle structures on the hydraulic efficiency of primary sedimentation tanks has been investigated by three-dimensional numerical modeling in Flow-3D software. In this study, the optimum number of baffles is studied to increase hydraulic efficiency. Settling tank in true size and simplified model primary settling tank treatment plant south of Tehran. The geometry Specifications of tank include of length tank (L) from the main inlet to the overflow output of 60 m, a width of tank (W) 12.9 m, water depth in normal mode (H) 3 m. the input flow rate to the tank 650 l/s. Model geometry using AutoCAD software and three-dimensional shape is drawn. In this study, from three mesh blocks to mesh geometry model is used. All three of these blocks in all directions are fully in touch with and the type of are linked blocks. Intended for three blocks, the size of the mesh is selected respectively, 5, 7 and 10 cm monotonically in each direction. In numerical modeling, the turbulence model used to solve turbulent flow and to solve pressure the GMRES method is used. In addition, the VOF technique to show the behavior of fluid on free surface flow and FAVOR technique have been used to simulate surfaces and geometric boundaries. Verification of numerical simulation results with former experimental data properly acknowledges the numerical results. It is already known the optimal location of the first baffle.
The results show that baffle causes the uniformity flow and increase removal efficiency of the primary sedimentation tanks. To determine the optimum number of baffles, the comparison results between no baffle tank and optimized cases with one, two and three baffle done. Using more baffles, in ideal conditions, causes suppression of the jet flow and more chances the suspended particles deposition. The addition of new baffles in suitable locations reduces the maximum velocity amount, the size of the circulation zones and kinetic energy and create uniform velocity vectors inside the settling zone. Volume circulation zones by using one, two and three baffles compared to non-baffle decreased 4.18, 4.44 and 4.56% of the total tank volume, respectively. Finally, the results of the FTC method for several cases indicated that using number of baffles lead to increasing the performance of the sedimentation tanks.

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Heat transfer through the internal supports of the cryogenic fluid tanks is an important issue in the tank design and manufacture. On the other hand, the internal supports strength should be enough to stand safely against the forces applied to the internal tank. From the heat insulation point of view, most of the polymers are suitable materials to use in the internal supports. But the low mechanical strength of the most of the polymers limits the life of the supports made from polymers. In this paper, a new composite support made from steel and polymer is presented for the internal supports. Multilayered design of the steel part of the presented supports controls the heat transfer through this part by adding more thermal contact resistance (TCR) to the heat flow path. An analytical model is developed to calculate TCR between layers of the steel part at various pressure and temperature conditions. A thermo-mechanical coupled finite element (FE) model is developed for the proposed support and solved by ANSYS FE code. Temperature distribution and heat flux of the presented support are investigated by FE analysis results. Heat flow through the new support design is compared with the heat flow of the supports constructed with polymer blocks. Comparison of the heat flow results shows that the amount of heat transferred to the cryogenic tank through the internal supports in the static loading condition decreases when using proposed composite design instead of polymer blocks.

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Roll motion is one of the most important and dangerous motions of the ship and can even result in capsizing of the vessel. Therefore, its control has been always of interest for marine industry researchers. Among the various methods and equipment for controlling the roll motion, the use of free surface anti-roll tanks has been one of the most important methods and which used in many cases due to its simplicity in construction and design. The high efficiency of these tanks at all speeds and even without speed is another strength of these tanks. This study investigates the effect of the free surface anti-roll tank on the roll motion numerically and experimentally. In the numerical simulation, a CFD sloshing solver, based on the “Open source Field Operation And Manipulation”, known in short as Open-FOAM, and assuming 2D laminar flow conditions, is customized to calculate the sloshing loads from the tank. The predicted roll damping and moments due to the anti-roll tank are validated against experimental results. This simulator could be used as a sloshing simulator to couple with seakeeping solvers.

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