Relationship Between Blast Overpressure and Shell Thickness on the Fluid Pressure on a Cylinder Under Blast Loading

2013 ◽  
Author(s):  
Veera Selvan ◽  
Namas Chandra
Keyword(s):  
Numerical Simulation ◽  
Intracranial Pressure ◽  
Blast Wave ◽  
Shell Thickness ◽  
Fluid Pressure ◽  
Human Head ◽  
Two Dimensional ◽  
Blast Overpressure ◽  
Simulation Results ◽  
Mechanical Insult

The mechanics of blast wave-head interaction determines the magnitude of mechanical insult to the human head during a field explosion and subsequent brain injury. In this work, blast overpressure and shell thickness are related to fluid pressure based on experimental and computational methods. A fluid-filled cylinder is idealized as a two-dimensional analog of a skull-brain complex and is subjected to a Friedlander blast wave. Strain and pressure on the surface of the cylinder and pressure in the fluid (analogue of Intracranial pressure) are experimentally measured and compared with numerical simulation results. The validated numerical model shows that fluid pressure increases linearly with increase in reflected overpressures (ROP) for a given shell thickness. When the ROP is kept constant, fluid pressure increases linearly with the decrease in shell thickness. An equation is developed for predicting the fluid pressure for a given ROP and shell thickness.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

Numerical Simulation of Small-Scale Explosion in Dry Sand

2013 ◽  
Vol 705 ◽  
pp. 110-114
Author(s):  
Yu Qing Ding ◽  
Wen Hui Tang ◽  
Xian Wen Ran ◽  
Xin Xu
Keyword(s):  
Numerical Simulation ◽  
Test Data ◽  
Detonation Product ◽  
Material Model ◽  
Small Scale ◽  
Two Dimensional ◽  
Material Models ◽  
Simulation Results ◽  
Dry Sand ◽  
Sand Material

Numerical simulation of small-scale explosion in dry sand using two sand material models including the Sand model and the LA model were carried out in the present study. Three cases were considered which the depths of burial (DOB) of the explosive C4 charge were 0, 30 mm and 80 mm, respectively. The time arrival of the blast-wave front and the maximum overpressure of fixed measuring locations were studied using a two dimensional axisymmetric model in hydrocode ANSYS/AUTODYN. Furthermore, the crater diameters and the heights of detonation product cloud respect to the time were also studied by comparing with the test data. The simulation results indicate that the both sand material models were hardly predict the test data exactly which proves that the sand properties and the material model should be more carefully studied and defined.

Effects of Materials on Formation of Double-Layered Liners Shaped Charges

2009 ◽  
Vol 79-82 ◽  
pp. 1277-1280
Author(s):  
Yu Zheng ◽  
Xiao Ming Wang ◽  
Wen Bin Li ◽  
Wen Jin Yao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Simulations ◽  
Double Layer ◽  
Two Dimensional ◽  
Materials Properties ◽  
X Ray ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Good Agreement

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.

An Assessment of Primary Blast Injury in Human Brains: A Numerical Simulation

2007 ◽  
Author(s):  
Mahdi Sotudehchafi ◽  
Ghodrat Karami ◽  
Mariusz Ziejewski
Keyword(s):  
Numerical Simulation ◽  
Blast Wave ◽  
Human Head ◽  
Blast Injury ◽  
Element Formulation ◽  
Pressure Waves ◽  
Arbitrary Lagrangian Eulerian ◽  
Wave Interactions ◽  
Structure Interaction ◽  
Human Brains

Most blast-related injuries happen as a result of complex pressure waves generated by the explosion. In this paper, we model the explosion from detonation and examine the blast propagation in air using Arbitrary Lagrangian–Eulerian (ALE) finite element formulation. The results of the simulation agree well with those of physical data obtained from blast wave experiments. Such results set the circumstances necessary for an examination of brain injury exposed to such situations. Thus the model will be coupled with a Fluid/Structure Interaction (FSI) algorithm to implicitly examine the blast wave interactions with a human head and to study the creation of high regions of biomechanics pressure and stress gradients.

scholarly journals Prediction and numerical simulation of residual stress in multi-pass pipe welds

2021 ◽  
Author(s):  
Mahmood Hasan Al-Hafadhi ◽  
Gyorgy Krallics
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Residual Stresses ◽  
Hardness Test ◽  
Element Model ◽  
Good Prediction ◽  
Two Dimensional ◽  
Residual Welding Stress ◽  
Welding Stress ◽  
Simulation Results

AbstractA numerical simulation procedure is presented to predict residual stress states in multi-pass welds in oil transportation pipes. In this paper, a two-dimensional thermo-mechanical finite element model is used to calculate the temperature distribution, hardness, and the distribution of residual stresses during multi-pass welding of pipes of dissimilar metals and varying thicknesses. In this model, the temperature dependence of the thermal and mechanical properties of the material was considered. The present model was validated using the hardness measurement. Good agreement was found between the measurement and the numerical simulation results. The simulated result shows that the two-dimensional model can be effectively used to simulate the hardness test and predict the residual stress in the pipe weld. The simulation results and measurements suggest that the model with moving heat source can obtain a good prediction of residual welding stress. Both the two-dimensional and the three-dimensional modeling can be used to estimate the residual stresses in different weld regions and help saving time.

Numerical Simulation of Masonry Wall under Explosive Load inside

2013 ◽  
Vol 712-715 ◽  
pp. 909-912 ◽  
Author(s):  
Juan Juan Liu ◽  
Yong Gang Lu ◽  
Jin Song Lei
Keyword(s):  
Numerical Simulation ◽  
Blast Wave ◽  
Masonry Wall ◽  
Rate Of Change ◽  
Von Mises Stress ◽  
Test Results ◽  
Explosive Load ◽  
Contrast Analysis ◽  
Simulation Results ◽  
Von Mises

The explosion process of masonry wall under interior explosive load was simulated by adopting the fluid-solid coupling method basing on the software ANSYS/LS-DYNA. The Von Mises stress nephograms and the contrast analysis of the numerical simulation results and test results were presented. The research indicates that mortar elements fails earlier than brick, a little difference exists between the sizes of the blasting hole in X and Y direction because of the transmission of blast wave in brick masonry, the size of blasting hole grows with the increase of weight of charge, and with the increasing charge, the rate of change declined gradually.

Optimization by Numerical Simulation of the Focusing Properties of Self-Magnetically Insulated Ion Diodes

1991 ◽  
Vol 02 (01) ◽  
pp. 536-540
Author(s):  
THOMAS WESTERMANN
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Power Density ◽  
The Self ◽  
Anode Surface ◽  
Two Dimensional ◽  
Simulation Results ◽  
Focusing Properties

We present two-dimensional electromagnetic computer simulation results performed in order to investigate the focusing properties of self-magnetically insulated ion diodes. It has been shown computationally that in the case of the self-magnetically insulated bθ-diode the power density can be improved by a factor 10 by changing the anode surface.

Numerical Simulation of Landslide Movement and Unzen-Mayuyama Disaster in 1792, Japan

2010 ◽  
Vol 5 (3) ◽  
pp. 280-287 ◽  
Author(s):  
Kuniaki Miyamoto ◽  
Keyword(s):  
Numerical Simulation ◽  
Volcanic Activity ◽  
Slip Surface ◽  
Two Dimensional ◽  
Ariake Bay ◽  
Landslide Volume ◽  
The World ◽  
Simulation Results ◽  
Topographical Analysis ◽  
Landslide Movement

Landslides may cause huge sediment disasters. To mitigate such sediment-induced disasters, the behavior of the landslide must be predicted, in addition to the time, the location of occurrence, and the scale of the landslide. This paper proposes a two-dimensional numerical simulation for landslides. The Mayuyama landslide of 1792, which was triggered by volcanic activity, caused one of the largest disasters in the world. To reproduce sediment movement resulting from this landslide, 2-D numerical simulation and topographical analysis are discussed. The topography of Mt. Mayuyama before the failure, the topography of the slip surface, and the characteristics of the landslide material are estimated for conducting numerical simulation. Results suggest that landslide volume is about 150 million m3 or more, the landslide probably reached the sea in only a minute, and the event may have been almost finished in a couple of minutes. Landslide velocity upon reaching the sea is estimated at 100 m/sec and the thickness of landslide front is estimated at 30 m, which are enough to generate a tsunami causing a huge disaster along the seashore of Ariake bay.

scholarly journals Laser-produced blast wave and numerical simulation using the FLASH code

2005 ◽  
Vol 23 (4) ◽  
pp. 513-519 ◽  
Author(s):  
D.R. FARLEY ◽  
K. SHIGEMORI ◽  
H. AZECHI
Keyword(s):  
Numerical Simulation ◽  
Temperature Profile ◽  
Blast Wave ◽  
Thermal Wave ◽  
Initial Temperature ◽  
Radiative Cooling ◽  
Gas Evolution ◽  
Two Dimensional ◽  
Nitrogen Gas ◽  
Spot Radius

Two-dimensional (2D) FLASH simulations were run with Spitzer-Härm conductivity on and off in an attempt to simulate a laser-produced blast wave. Dissociation, ionization, recombination, and radiative cooling were not included. An initial Gaussian temperature profile with T0 = 120 eV and spot radius r0 = 25 μm was used assuming 1 μm thickness of the CH disk is ablated into the background nitrogen gas. Evolution of the blast wave differs slightly between the cases of Spitzer-Härm on and off, and neither case matches well with experiment. Due to the high temperatures involved, a thermal wave should be expected such that the Spitzer-Härm conductivity on case is more likely. A simulation run with an initial temperature of ∼ 4 keV might match better with experiment.

Thermal Radiative Properties of a Two-Dimensional Silicon Carbide Grating Mediated With a Photonic Crystal

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Weijie Wang ◽  
Yi Zhao ◽  
Wenchang Tan ◽  
Ceji Fu
Keyword(s):  
Numerical Simulation ◽  
Silicon Carbide ◽  
Photonic Crystal ◽  
Radiative Properties ◽  
Two Dimensional ◽  
Thermal Radiative Properties ◽  
Surface Phonon Polaritons ◽  
Magnetic Polaritons ◽  
Phonon Polaritons ◽  
Simulation Results

We present in this paper numerical simulation results of the thermal radiative properties of a two-dimensional (2D) rectangular SiC grating atop a photonic crystal (PC). The results show that surface phonon polaritons (SPhPs) can be excited by both TE and TM waves when they are scattered by the 2D grating. Excitation of SPhPs, PC modes, and magnetic polaritons (MPs), and interactions between them give rise to great enhancement of the emissivity. Distinct effects of the grating geometry on the resonance of SPhPs, PC modes, and MPs were revealed, which suggest a way to effectively manipulate the emissivity by tuning the structure's geometry. Furthermore, the results indicate that quasi-diffuse emissivity of the structure can be obtained for both TE and TM waves.

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