Numerical Study of the Dynamic Response of Elevated Steel Conical Tank under Vertical Seismic Excitation-Case Study

Elevated cylindrical and conical steel tanks are widely used to conserve water or chemical liquids. These important structures are required to stay protected and operative at any time. The wall angle inclination of conical tank part, as well as the presence of the vertical earthquake component, can cause damage to this structure and even lead to its failure. The purpose of this study is to examine the effect of wall angle inclination of the tank and the vertical earthquake acceleration component on the nonlinear dynamic stability of the elevated steel conical tanks under seismic excitation. The elevated steel conical tank is simulated utilizing the finite element analysis method using ANSYS software. The fluid-structure interaction is considered using a suitable interface that allows the fluid to apply hydrodynamic pressures on the structure. Three different models, namely Model -A-30 degrees, Model -B-45 degrees and Model -C-60 degrees are investigated; it has been concluded that the impact of inclination of the tank wall significantly affects the nonlinear stability of the elevated steel conical tank. While considering the vertical ground acceleration, inclination plays a significant role in the design of this type of structures. Therefore, it should be appropriately included in the seismic analysis of elevated steel conical tanks to satisfy the safety of the elevated steel conical tank response under seismi

Effect of Geometric Imperfection on the Dynamic of Elevated Water Tanks

The elevated tanks are considered as very sensitive structures in seismic movement condition. Moreover, the conical steel tank manufacturing without local geometric imperfection seems to be too difficult. In generally, the latter is the most responsible factor to define the shell structures buckling capacity. For this reason, several theoretical and experimental researchers studied the performance of this type of structure under seismic loading.  The present study aims to demonstrate the local geometric imperfection effect on dynamic buckling of elevated water tank. Using the three dimensions finite element technique to study the seismic response of perfect and imperfect elevated water tank was established taking into account the following factors; the interaction fluid structure (FSI), the wall flexibility, the local geometric imperfection, the nonlinear time history analysis, the material and geometric nonlinearity, and this by the application of three different instability criteria for the critical PGA estimate. The critical PGA of the imperfect elevated water tank numerical models decreased by 45, 45% compared to the elevated water tank numerical model without local geometric imperfection. The obtained results confirm the local geometric imperfection effect on dynamic buckling of elevated water tanks

Effect of Geometric Imperfection on the Dynamic of Elevated Water Tanks

The elevated tanks are considered as very sensitive structures in seismic movement condition. Moreover, the conical steel tank manufacturing without local geometric imperfection seems to be too difficult. In generally, the latter is the most responsible factor to define the shell structures buckling capacity. For this reason, several theoretical and experimental researchers studied the performance of this type of structure under seismic loading.  The present study aims to demonstrate the local geometric imperfection effect on dynamic buckling of elevated water tank. Using the three dimensions finite element technique to study the seismic response of perfect and imperfect elevated water tank was established taking into account the following factors; the interaction fluid structure (FSI), the wall flexibility, the local geometric imperfection, the nonlinear time history analysis, the material and geometric nonlinearity, and this by the application of three different instability criteria for the critical PGA estimate. The critical PGA of the imperfect elevated water tank numerical models decreased by 45, 45% compared to the elevated water tank numerical model without local geometric imperfection. The obtained results confirm the local geometric imperfection effect on dynamic buckling of elevated water tanks.</jats:p

Dispersion d'ions en écoulement gazeux homogène et isotrope

A study which deals with the dispersion of electric charges driven by a flow of gas has been carried out. The suggested patterns takes interaction and diffusion phenomenons into account; the solutions requiring a finished explicit differences method have been established for a distribution of charges with an axial symmetry. The numerical results obtained have enabled us to characterize the influence of mobility and diffusion parameters. An experimental comparison has been conducted, in which significant prospects for the estimation of the diffusion constants appeared.Une étude de la dispersion de charges électriques entraînées par un gaz a été réalisée. Le modèle proposé prend en compte les phénomènes d'interaction et de diffusion ; les solutions faisant appel à une méthode aux différences finies explicite ont été établies pour une distribution de charges à symétrie axiale. Les résultats numériques obtenus ont permis de caractériser l'influence des paramètres de mobilité et de diffusion ; une confrontation expérimentale a été effectuée et laisse apparaître des perspectives intéressantes pour l'évaluation des constantes de diffusion

Discharge flow of a bidisperse granular media from a silo

International audienceThe discharge flow in a cylindrical and a rectangular silo using both monodisperse and bidisperse mixtures of spherical glass beads is studied experimentally. The flow rate is measured using a precision balance for a large range of particle diameters, size ratios, and outlet diameters. A simple physical model is proposed to describe the flow of bidisperse mixtures. It gives an expression for the flow rate and predicts that the bulk velocity follows a simple mixture law. This model implies that a mixture diameter cannot be simply defined. Moreover it is shown that bidisperse granular media allow for the transport of coarse particles below their jamming conditions

Insight into the influence of the polymerization time of polydopamine nanoparticles on their size, surface properties and nanomedical applications

In the last decade, novel strategies to synthesize polydopamine nanoparticles (PDA NPs) have been continuously developed owing to useful applications of this synthetic melanin analog in nanotechnology.</jats:p