civil engineering
Mohammad Hossein Taghizadeh Valdi; Edris Merufinia
Abstract
In this article, the water entry problem of reticulated pounder including 4, 9, 16, 25 and 64 holes which are distributed with a matrix arrangement on the surface of the pounder, is investigated numerically and to model the interaction between the pounder and fluid, an explicit dynamic analysis was employed ...
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In this article, the water entry problem of reticulated pounder including 4, 9, 16, 25 and 64 holes which are distributed with a matrix arrangement on the surface of the pounder, is investigated numerically and to model the interaction between the pounder and fluid, an explicit dynamic analysis was employed using the Eulerian-Lagrangian couple formulation available in the commercial finite element software Abaqus 6.14-2. The results of the numerical solution were validated by comparing and matching the numerical, theoretical and experimental results of the trajectory of a spherical projectile in the depth of water, including the shape of the air bubble formed and the pinch-off time and depth, which indicated the accuracy and application of the numerical algorithm used. The results of the current research showed that the 9-hole pounder reaches the model bed at a depth of 100 cm in less time than other pounders with different arrangement and number of holes. In 16- and 25-hole pounders, the ratio between the mass of the pounder and the area of the holes is unstable, and due to the decrease in the area of the holes, the effect of water resistance on the bottom of the pounder increases when it moves in its depth. The effect of increasing the mass of the pounder on reducing the duration of its immersion in the water depth is more evident in the 64-hole pounder. So that this pounder has a smaller area of holes compared to other pounders, it has more mass with smaller holes than other pounders, and despite the smaller dimensions of the holes and the increase in the life of the reticulated pounder, which is the factor that increases the resistance of the water entering the pounder floor, due to the large mass of the pounder, it overcomes the water resistance that is applied as an upward force on the bottom of the reticulated pounder, and the duration of its movement in the depth of the water is reduced from the moment it hits the free surface of the water until it reaches the model bed.
civil engineering
Morvarid Hajian; Reza Attarnejad
Abstract
The soil-structure interaction is one of the most important challenges in structural design that can significantly change the seismic response of structures. . During an earthquake, the behavior of the soil under the structure plays an important role in the response of the structure and affects the dynamic ...
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The soil-structure interaction is one of the most important challenges in structural design that can significantly change the seismic response of structures. . During an earthquake, the behavior of the soil under the structure plays an important role in the response of the structure and affects the dynamic characteristics of the structure. Therefore, there is a need for more accurate modeling of the soil environment in special structures. In engineering applications, the soil is often not modeled and its important effects are neglected, due to the unlimited nature of the soil environment and its modeling is more complicated than the structure modeling. There are different methods for modeling the soil-structure interaction phenomenon. One of the most popular methods is the method of beam on the elastic foundation. This method is based on the Winkler model, which is widely used in the design codes, but does not accurately show the changes in soil stiffness along the length of the foundation. Therefore, in the present article, the reaction of the soil under the foundation is investigated, and finally, a suitable and simplified model is presented for modeling the soil-structure interaction in engineering applications.To achieve this goal, several structures were modeled in 3D in the OpenSees environment. Then, the output of the reaction of the soil environment and the foundation of the structure has been used to estimate the hardness of the soil environment and foundation and extract simplified engineering relations
