Numerical Study of the Influence of Internal Blast on the Earth Covered Composite Arch

2014 ◽  
Vol 982 ◽  
pp. 84-89
Author(s):  
Jindrich Fornůsek ◽  
Jan Zatloukal
Keyword(s):  
Numerical Study ◽  
Blast Load ◽  
The Earth

This paper presents a numerical study of earth covered composite arch subjected to internal blast load equaled to 6,25 tons of TNT. The concrete arch was protected against the blast by the 4 or 7 mm corrugated sheet. There was also one simulation where no sheet was applied. It was found that the presence of the corrugated sheet anchored to the arch can reduce 40 % of arch damage compared to the unprotected arch.

scholarly journals A numerical study for convection in a cylindrical model with continuously varying viscosity

1996 ◽  
Vol 39 (3) ◽  
Author(s):  
F. Fanucci ◽  
A. Megna ◽  
S. Santini ◽  
F. Vetrano
Keyword(s):  
Viscosity Solutions ◽  
Numerical Study ◽  
Viscosity Coefficient ◽  
Cylindrical Symmetry ◽  
The Earth ◽  
Realistic Representation ◽  
Convective Motions ◽  
Constant Viscosity ◽  
Varying Viscosity ◽  
Better Than

In the framework of a cylindrical symmetry model for convective motions in the asthenosphere, a new profile for the viscosity coefficient depending on depth is suggested here. The numerical elaboration of the above mentioned model leads to interesting results which fit well with experimental observations. In particular these continuously varying viscosity solutions probably describe the convective motions within the Earth better than simple constant viscosity solutions. Consequently the temperature values seem to be a realistic representation of the possible thermal behaviour in the upper mantle.

scholarly journals Numerical Simulation of Blast Loaded CFRP Retrofitted Steel Plates

2021 ◽  
Vol 347 ◽  
pp. 00038
Author(s):  
Mujtaba M. Shuaib ◽  
Steeve Chung Kim Yuen ◽  
Gerald N. Nurick
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Structural Response ◽  
Steel Plates ◽  
Blast Load ◽  
Cylindrical Charge ◽  
Arbitrary Lagrangian Eulerian ◽  
Finite Element Software ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper reports on the results of a numerical study to simulate the response of carbon fibre reinforced polymer (CFRP) retrofitted steel plates to applied blast loads using finite element software, LS-DYNA. The results of the simulation were validated against plate response and magnitude of deformation obtained from previous experiments. The uniform blast load was generated in the experiment by detonating a cylindrical charge down the end of a square tube. The finite element code LS-DYNA was used to simulate the structural response of the respective blast structures. For the numerical model, the blast load was simulated using the mapping feature available in LS-DYNA for the multi-material arbitrary Lagrangian-Eulerian (MM-ALE) elements which significantly reduced the size of the air domain in the model. The simulations showed a satisfactory correlation with the experiments for the blast results and post-failure deformations that occurred in CFRP retrofitted steel plates.

scholarly journals PREDICTING THE STRUCTURAL PERFORMANCE OF SANDWICH CONCRETE PANELS SUBJECTED TO BLAST LOAD CONSIDERING DYNAMIC INCREASE FACTOR

2019 ◽  
Vol 10 (1) ◽  
pp. 45-58
Author(s):  
Mohammad Hanifehzadeh ◽  
Mir Mohammad Reza Mousavi
Keyword(s):  
Numerical Study ◽  
Near Field ◽  
Concrete Strength ◽  
Plate Thickness ◽  
Superior Performance ◽  
Blast Load ◽  
Structural Performance ◽  
Concrete Core ◽  
Explicit Finite Element ◽  
Maximum Deformation

The safety of the civil structures could be significantly improved against shock waves and blast loads by using steel concrete steel (SCS) protective walls. A numerical study has been performed to simulate the response of SCS wall subjected to a near-field blast load. A conventional SCS panel subjected to near-field blast load and its structural performance is evaluated in terms of maximum damage and deformation. The simulations performed using ABAQUS\EXPLICIT finite element package and built-in concrete damage plasticity concrete constitutive formulation. The maximum deformation, plastic strain, and failure mode under different loading scenarios have been investigated. The aim of this study is predicting the structural response of the SCS panel with different blast charge and identification of optimum configuration in terms of concrete strength and plate thickness. In the second part of the study, two novel sandwich configurations consisting of a corrugated metal sheet and the concrete core are proposed and compared with the conventional protective walls. The optimum parameters for each structural component are identified using an optimization procedure. Based on this study, using the proposed wall configuration will results in superior performance compared to the conventional walls while the extra cost of fabrication is insignificant.

scholarly journals The Contribution of Kuiper Belt Dust Grains to the Inner Solar System

1996 ◽  
Vol 150 ◽  
pp. 163-166
Author(s):  
Jer-Chyi Liou ◽  
Herbert A. Zook ◽  
Stanley F. Dermott
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Numerical Study ◽  
Kuiper Belt ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Dust Grains ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
The Earth

AbstractThe recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population at 1 AU. We have completed a numerical study of the orbital evolution of dust grains, of diameters 1 to 9 μm, that originate in the region of the Kuiper belt. Our results show that about 80% of the grains are ejected from the Solar System by the giant planets while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, these dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances to be captured by the Earth and makes them a possible source of the collected interplanetary dust particles (IDPs); in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth.When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains larger than about 9 μm appear likely to be collisionally shattered before they can evolve to the inner part of the Solar System. Therefore, Kuiper belt dust grains may not, as they are expected to be small, contribute significantly to the zodiacal light.

An unknown maximum lag-correlation between rainfall and aerosols at 140-160 minutes

2021 ◽  
Author(s):  
Pinhas Alpert ◽  
Haim Shafir ◽  
Emily Elhacham
Keyword(s):  
Time Series ◽  
Time Scales ◽  
Atmospheric Chemistry ◽  
Numerical Study ◽  
Aerosol Concentration ◽  
Hygroscopic Growth ◽  
Plain Language ◽  
Geophysical Research ◽  
Near Surface ◽  
The Earth

<p>Keywords:</p><p>Scavenging process, Rainfall, Aerosols, Lag correlation, Rainfall-aerosol processes</p><p>Abstract</p><p>Rainfall and aerosols play major roles in the Earth climate system and substantially influence our life. Here, the focus is on the local near-surface aerosol/rainfall correlations with time-scales of minutes to days. We investigated 29 experiments including 14 specific rain events, with time resolutions of daily and 60, 30, 10 minutes at ten stations in Israel and California. The highest negative correlations were consistently at a positive lag of about 140-160 minutes where a positive lag means that the aerosol time-series follows that of the rain. The highest negative value is suggested to be the probable outcome of immediate scavenging along with the rise in aerosol concentration after rain depending on aerosol sources, hygroscopic growth and transport. The scavenging dominance is expressed by the mostly negative lag-correlation values in all experiments. In addition, the consistent lack of significant correlation found at negative lags suggest a weak aerosol effect on precipitation (Gryspeerdt et al., 2015).</p><p>Plain Language Summary: Rainfall and atmospheric particles (aerosols) play significant roles in the Earth atmosphere and largely influence our weather and climate. The relations between near-surface aerosol and rainfall on time scales of minutes to days are studied, employing correlations in 10 meteorological stations in Israel and California. The highest negative correlations were consistently at a positive lag of about 140-160 minutes. A positive lag means that the aerosol time-series follows that of the rain. The highest negative correlation value is suggested to be the outcome of scavenging along with the rise in aerosol concentration after rain depending on the sources of aerosols, hygroscopic growth and transport. <strong>Furthermore, our approach provides a more fundamental insight into the local, near-surface rain-aerosol interactions, in contrast to many aerosol-rainfall studies that are climatological and with the tele-connection approach (Alpert et al., 2008), which involves other processes over distances of a few km up to even large synoptic scales.</strong></p><p>            </p><p><strong>Relevant References:</strong></p><p>Alpert, P., Halfon, N., & Levin, Z. (2008). Does Air Pollution Really Suppress Precipitation in Israel? Journal of Applied Meteorology and Climatology. https://doi.org/10.1175/2007jamc1803.1</p><p>Barkan, J., & Alpert, P. (2020). Red Snow occurrence in Eastern Europe - A case study. Weather. https://doi.org/10.1002/wea.3644</p><p>Gryspeerdt, E., Stier, P., White, B. A., & Kipling, Z. (2015). Wet scavenging limits the detection of aerosol effects on precipitation. Atmospheric Chemistry and Physics, 15(13), 7557–7570.</p><p>Tsidulko, M., Krichak, S. O., Alpert, P., Kakaliagou, O., Kallos, G., & Papadopoulos, A. (2002). Numerical study of a very intensive eastern Mediterranean dust storm, 13-16 March 1998. Journal of Geophysical Research: Atmospheres. https://doi.org/10.1029/2001jd001168</p>

scholarly journals Behaviour and Failure of Steel Columns Subjected to Blast Loads: Numerical Study and Analytical Approach

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Haitham Al-Thairy
Keyword(s):  
Parametric Study ◽  
Analytical Approach ◽  
Numerical Study ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Design Procedure ◽  
Blast Load ◽  
Blast Loads ◽  
Steel Columns ◽  
Failure Patterns

The main objective of this study is the numerical simulation of the behaviour and failure patterns of steel columns under blast loads using the dynamic finite element package ABAQUS/Explicit. A numerical model is suggested and validated against published experimental tests on full-scale wide-flange steel columns subjected to dynamic blast loads under constant axial compressive force. Afterwards, the validated model is used to investigate the effect of important parameters on the behaviour and failure patterns of steel columns under blast pressure through an extensive parametric study. The parameters include the blast impulse, the blast energy, the blast load, the blast duration, the column boundary condition, the column slenderness ratio, and the blast direction. The conclusions extracted from this parametric study may be used to develop a thorough understanding of the behaviour and failure of steel columns subjected to blast load which, in turn, could lead to a more accurate practical design procedure. The study also presents derivations and validations of a proposed analytical approach to calculate the critical blast impulse at which a steel column losses its global stability. Comparison between the critical impulse-axial force curves obtained from the proposed equation and that extracted from numerical simulations indicates the validity and feasibility of the proposed equation.

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