Instituto Superior Técnico

Infill panel is the first element of a building subjected to blast loading activating its out-of-plane behavior. If the infill panel does not have enough ductility against the loading, it breaks and gets damaged before load transfer and energy dissipation. As steel infill panel has appropriate ductility before fracture, it can be used as an alternative to typical infill panels under blast loading. Also, it plays a pivotal role in maintaining sensitive main parts against blast loading. Concerning enough ductility of the infill panel out-of-plane behavior, the impact force enters the horizontal diaphragm and is distributed among the lateral elements. This article investigates the behavior of steel infill panels with different thicknesses and stiffeners. In order to precisely study steel infill panels, different ranges of blast loading are used and maximum displacement of steel infill under such various blast loading is studied. In this research, finite element analyses including geometric and material nonlinearities are used for optimization of the steel plate thickness and stiffener arrangement to obtain more efficient design for its better out-of-plane behavior. The results indicate that this type of infill with out-of-plane behavior shows a proper ductility especially in severe blast loadings. In the blasts with high intensity, maximum displacement of infill is more sensitive to change in the thickness of plate rather the change in number of stiffeners such that increasing the number of stiffeners and the plate thickness of infill panel would decrease energy dissipation by 20 and 77% respectively. The ductile behavior of steel infill panels shows that using infill panels with less thickness has more effect on energy dissipation. According to this study, the infill panel with 5 mm thickness works better if the criterion of steel infill panel design is the reduction of transmitted impulse to main structure. For example in steel infill panels with 5 stiffeners and blast loading with the reflected pressure of 375 kPa and duration of 50 milliseconds, the transmitted impulse has decreased from 41206 N.Sec in 20 mm infill to 37898 N.Sec in 5 mm infill panel.

In blast loading, out-of-plane behavior of infill wall is activated initially. Contrary to other types of infill wall such as brick or concrete wall, infill steel plate wall exhibits more ductility. Since blast impulsive loading suddenly exerts a large amount of kinematic energy to infill wall, energy absorption characteristic of the infill wall should be taken into account, especially for protection of vulnerable buildings. Out-of-plane ductility of infill steel plate reduces the transmitted impulsive loading to the structure. In present study, out-of-plane behavior of infill steel panel has been studied as a sacrificial element. In-plane behavior of infill steel panel is also investigated as a lateral bearing system. In-plane action should satisfy both resistance and performance criteria. In this research, finite element analysis, including geometric and material nonlinearities is used for optimization of the steel plate thickness and stiffeners arrangement to obtain more efficient design for out-of-plane and in-plane actions. The results of analyses show that for out-of-plane action, the plate thickness and stiffeners arrangement can be determined such that on one hand, the impulse transmission can be minimized, and on the other hand, the maximum residual deformation can be limited to the predefined damage level. Additionally, the effect of stiffener arrangement on the performance of in-plane are studied and some practical rules have been derived for designing the infill steel panel against blast.

The main end of this study is reaching a comprehensive perspective of the performance of different glass panel walls against various impulsive loads in order to mitigate the effects of these challenging loads on the main structure. In this study, an accurate comparison of the structural behavior of different glass panels is presented. To assess the ductility and energy dissipation of different panels, a wide range of parameters are considered. As a matter of fact, with comparing the ductile behavior of different glass panels and their energy dissipation, the glass panel with the best performance against severe blast loads will be recommended in this study. The blast behavior of different laminated glass panels in the two phases of pre-crack and post-crack will be studied. As a novelty, more than 500 finite element models are modeled for optimization of LG panels to obtain more efficient design. To achieve these goals, diverse kinds of glass panels with different thicknesses and dimensions are utilized.

The behavior of steel plate walls (SPWs) under various impulsive loadings and the effects of different mesh sizes are investigated in this paper. With the aim of accurately inspecting SPWs, a series of analyses with 250 models with different plate geometric assumptions and different blast impulsive loadings are performed to study the SPWs’ out-of-plane behavior. The mild steel material specifications are adopted for SPWs with different thickness and stiffener arrangement and ABAQUS software is utilized for the Finite Element analysis. Re-sults of transferred impulse, maximum displacement and von Mises Stress of SPWs show that SPWs with thickness of 5 mm are the best choice against various impulsive loadings in comparison with SPWs with thickness of 20 mm. In fact, the SPWs having the thickness of 5 mm show better performance as a result of more energy dissipation against various impulsive loadings. Finally, the von Mises stress contours investigated for some models show 28% more stress in P5 SPW than that in P20 SPW. Also, it can be concluded that various sizes of mesh have no remarkable effect on unstiffened SPW while effect of different mesh sizes is more significant with increasing the number of stiffeners.

A blast is able to cause structural failure, collapse of walls leadings to damage infill panels of structure. This article investigates the behavior of steel infill panels with different thickness and stiffeners using finite element analysis with geometric and material nonlinearities for optimization of the steel plate thickness and stiffeners arrangement to obtain more efficient design for its out-of-plane behavior. In this research, the mild steel material specifications are adopted for infill panels. The ABAQUS commercial code is used for finite element analyses of steel plates, and the Cowper-Symond is used for considering strain rate dependency. The damping effect has been considered via Rayleigh damping coefficients in all models.

This study investigates the ductility of steel plate walls with different thicknesses and stiffener arrangements. In order to study steel plate walls, various blast loading including 250 models are used. According to ASCE design recommendations, blast loading has prescribed by peak reflected over pressure and time duration of loading.
In this study, finite element analyses are utilized. In this research, the behavior of these walls are investigated especially in severe blast loading.

This study presents a numerical study on the effect of stiffener positions on the blast resistance of steel building infill panels. ABAQUS was used to create models of the various configurations and the deflections and load transfer characteristics of the various configurations were studied for three loading scenarios. Also, in-plane behavior of steel infill panels was investigated accurately. In this research, the steel infills with in-plane behavior were considered as shear walls. In these walls, the base shear-drift diagrams were studied.

In this project, a comprehensive study on different systems utilized to mitigate the effects of extreme loads on timber structures is accurately conducted. Especially, the effect of using Tuned Mass Damper (TMD), as a great device to reduce the peak acceleration values, is considered. Moreover, an accurate investigation on the behavior of the connections of timber structures with focusing on the amount of their energy dissipation under extreme loads, such as blast, earthquake and wind loads, is presented. As a matter of fact, one of the most important goals of this study is comparing different methods for improving the performance of connections in timber structures. Finally, the structural system with the best performance in reducing the effects of extreme dynamic loads on timber structures is approved.

The main aim of this project is the control of buckling of steel plate shear walls by taking into account different methods such as using different stiffener arrangements and various thicknesses to prevent tension field which causes excessive strength. Moreover, the effects of different parameters on the progressive collapse of steel plate shear walls are investigated accurately. Finally, some suggestions will be put forth to solve these problems.

Detailed kinetics of N2O conversion and carbon gasification over solids comprised of activated carbon impregnated with Ba, Co, Cu, Fe, Mg, Mn, Ni, Pb and V precursors salts were studied using a GC/MS system. The gasification rates of carbons impregnated with binary mixtures of Mn with other metals were also tested in the temperature range between 300 and 800°C using