جستجوی مقالات مرتبط با کلیدواژه « blast » در نشریات گروه « مواد و متالورژی »

The walls placed in structural frames can act as a loading surface against the explosion load and significantly increase the dynamic load applied to the structural members. Therefore, the durability of the walls against the blast load and how they are connected to the structural members may have a significant effect on the dynamic response of the structures to the blast load. To investigate this subject, finite element method and Abaqus software are used. Initially, to ensure the accuracy of the predictions of finite element model, verification is performed by modeling an explosive experiment on a concrete-filled steel tube column and a good agreement is observed. Then, the effect of the presence or absence of a concrete wall in the frame and how it is connected to the beam and column is investigated using dynamic explicit analysis. The results of the study showed that in the case of no wall and in the case where the wall is attached to the column only, the highest amount of plasticity has occurred in the beam. In specimens with wall-to-column connection, the maximum plastic strain is observed at the base of the column. The existence of infill wall and the attachment to a beam or column has a significant effect on the vertical displacement of the beam.

In recent years, with the increasing number of terrorist attacks and explosions in structures, extensive studies have been carried out on the performance of structures and their reactions under blast load. Due to the importance of the pile in the load transfer of various structures such as wharves, oil platform and bridges it is essential to study the behavior of this member. In this research, to minimize the damage caused by the blast load and the waves caused by the blast, the behavior of steel piles in two types of loose and dense sandy soil was investigated by Abaqus. The modeled pile is placed under different blast loads at 5 m distance from the pile head (at the soil surface) and the end of the pile (at the soil depth) has been studied. Finally, it was observed that the bending moment pile in dense sandy soil was significantly more than bending moment pile in loose sandy soil. The horizontal displacement of the pile head when the blast occurred at the soil surface is far greater than the displacement of the pile head under the blast load.

Earthquake and explosion are destructive dynamic forces. These forces can cause severe damage to the structure due to the time-dependent nature of the impact. One of the most important parameters for checking the stability of structures is the study of their buckling modes. The stability check has a direct relationship with the critical load of the columns. In this paper, the effects of simultaneous explosions and nearearthquake earthquakes on the stability of structures are investigated. The purpose of this research is to numerically simulate the state that earthquake-induced vibrations cause explosives to explode near structures. Therefore, the dynamic and buckling behavior of structures under the effects of earthquake and explosion have been investigated. In this article, the explosion enters the structure in three phases with the earthquake simultaneously. These three stages include before the earthquake, at the time of the earthquake and after the earthquake. In this regard, in this paper, structures are affected by internal and external structural explosions and the simultaneous effects of earthquakes. This article has shown that the most critical situation is when the vibrations caused by an earthquake trigger an explosion during its strong movement. The results of this paper show that the combination of explosion and earthquake is not very effective if the explosive is more than 500 kg TNT. In fact, earthquakes in this case have little effect on the nonlinear response of the structure. In this paper, it is shown that the effects of P-Delta consideration do not have much effect on the structure response. Based on the results provided for different explosions and earthquakes, it can be seen that the combination of explosion and earthquake has a greater effect on dynamic analysis.

Reinforced concrete (RC) structures are widely used in urban buildings and infrastructures, and these are always subjected to explosions caused by intentional or unintentional accidents. Among the structural members, columns are key load carrier elements. In this paper, behavior of RC columns with circular and square sections strengthened by steel jackets is investigated and compared under blast loading. Accordingly, six circular columns and six square columns, which are equivalent in geometry and material properties, were modeled using ABAQUS software package. The effect of varying the concrete strength, longitudinal reinforcement and geometrical properties of steel jacket on FE models of the columns has been studied. In addition, a sub-program has been written to evaluate the changes in axial and lateral capacity of the column. Based on the most important results, the circular columns perform better under blast loading. Using steel jackets, in addition to increasing the explosive capacity of the column, improves the effects of other remediation strategies such as the use of high strength concrete and the higher percentage of reinforcement. This effect was observed to be higher in circular columns in compare to square columns.