Problem Of Simulating Spallation Phenomena

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observed phenomena on dynamic brittle fracture are reproduced in our molecular dynamics simulations. We first summarize the molecular dynamics simulation technique, followed by a description of our model system for simulating dynamic fracture. A short introduction

Computational Fluid Radiative Dynamics of The Galileo Jupiter

the e ects of spallation and inclusion of vacuum ultraviolet (VUV) bands for C 2 and C 3 species were incorporated in the radiative analysis. More recently, Reynier et al. compiled the state-of-the-art in the modeling of giant-planet atmospheres for convective heating predictions, and reviewed previous attempts in simulating the Galileo entry [1].

Thermal Hydraulic Study For Heavy Liquid Metal Flows Using

critical reactor and spallation target [1]. It is also the coolant considered in the design of Compact High Temperature Reactor (CHTR) in BARC[3]. On the other hand LLE is preferred as the coolant in Indian LLCB TBM planned for testing in ITER, Cadarche[2]. Thermal Hydraulics of liquid metals have to be studied before the process design.

Natural and Gas-injection Enhanced Circulation in a Loop with

adequacy of its models for simulating the thermal-hydraulic phenomena involved in ADS cooling. II. Experimental Facility Fig. 1 shows a sketch of the experimental facility adopted in the present work. It mainly consists of 1½ I.D. pipes welded or connected by flanges to each other. The main

Synergistic Effects of Radiation Damage and Plasma-Material

to determine the most faithful way of simulating DT neutron damage using (multiple) ion beams for achieving relevant dpa-to-helium ratios. For option #2, some key issues need further study to determine the relevance of serial material exposure to the integrated radiation damage and PMI envi-ronment of CTF/FDF/DEMO.

Numerical Investigation of Three-Dimensional Effects within a

simulating the multidimensional heat transfer phenomena tha -Spallation prediction capability of a typical problem, uses the popular

EURAC: A Concept for a EURopean ACcelerator Neutron Source

the feasibility of spallation neutrons to simulate the Tokamak fusion reactor first wall conditions. It can be shown that spalla- tion neutrons, produced by 600 MeV protons impinging on a thin lead target are simulating the fusion reactor first wall con-

Influence of the 3-D Phenomena on the Safety Parameters

phenomena occurring in a pool type reactor. The objective of this work is to assess the shortcomings of 1-D system codes in predicting the response of the MYRRHA reactor to a LOF event, identifying the 3-D safety-relevant phenomena that can have an influence on the transient evolution.


Sep 10, 2019 simplifies considerably the problem and it can be calculated in a rather straightforward way. This simplified transport theory is known as neutron diffusion equation and it is shown in the following: ∇2 𝑎𝜙+ = 1 𝑣 𝜕𝜙 𝜕𝑡. (3) However, many diffusion problems can not be solved by the analytical techniques; they have

LA-UR- 96-1587

bum, shock transition, fluid and elastic-plastic flow, failure by spallation or fracture, magnetohydrodynamics. These diverse processes generally occur in localized regions of the problem. Thus the very partial differ- ential equations used to mathematically model the problem change from one region of space and time to another.

18th International Conference on Structural Mechanics in

ISBN: 978-1-5108-1701-2 18th International Conference on Structural Mechanics in Reactor Technology 2005 (SMiRT 18) Beijing, China 7-12 August 2005

The Application of a Cyclotron in Materials Research at the

cycle). The spallation behaviour at 900 DC was more irregular. However, long term testing [15] showed that also in this case an approximately linear behaviour applies with a Cr spallation rate of about 0.4 flg/(cm 2 cycle). In the case of a maximum test temperature of 800 ec, no spallation could be observed.

Effects of Particle Size, Gas Temperature and Metal

with larger particles causing significant TBC spallation during a 4-hour accelerated test. In the second series of tests, different gas temperatures were studied while the facility maintained a constant exit velocity of 170m/s (Mach=0.23-0.26). Coal ash with a mass mean diameter of 3µm was used.

Gear Diagnostics Fault Type Characteristics

the gear, simulating a fault of the spall/pitting type. The single tooth defect (figure 3) was seeded by a removal of material from the tooth face at a portion of the tooth s width. In similarity to the effect of a common spallation (or pitting) on tooth meshing, the presence of the fault reduces

arXiv:physics/0010001v1 [physics.acc-ph] 30 Sep 2000

provement in simulation capability, in terms of problem size and speed of execution, compared with typical two-dimensional serial simulations. Specific examples will be presented, including simulation of the spallation neutron source (SNS) linac and the Low Energy Demonstrator Ac-celerator (LEDA) beam halo experiment. 1 INTRODUCTION

A. Hassanein and I. Konkashbaev Energy Technology Division

hydrodynamic phenomena should be taken into account when modeling and simulating the fragmentation of suddenly heated liquid metal jets. Sudden energy deposition causes an instant rise in temperature that leads to a corresponding rise in the thermal pressure that causes excitation of sound waves, i.e., shock waves and rarefaction waves.


600 500 E £ 400 ^ 300 w 200 * 100 0.5 1. 5 2 2. Time / p 3.5 FIGURE 2. The spall traces of AQ80, impacted at 256,461 and 585 m s~l.Solid lines are experimental data, hatched lines with

Research Article Study of Hypervelocity Projectile Impact on

various aspects of this problem for several decades. A com- suggested that spallation damage and phase-transition phenomena in LS-DYNA [], using a constitutive material


Erosion of engine compressor blades, for example, is a severe problem for a vehicle operating in desert areas or for aircraft using unpaved landing strips, rough terrain, etc. Damage caused by eroding particles, such as sand, dust or volcanic ash, lowers the engine power,


larger particles causing significant TBC spallation during a 4-hour accelerated test. In the second series of tests, particle deposition rate was found to decrease with decreasing gas temperature. The threshold gas temperature for deposition was approximately 960°C. In the third and fourth test series

BARC NEWSLETTER Home Founder s Day

phenomena. Berlin: Spring-Verlag (1999). 3. Ikkurthi VR, Chaturvedi S, 2004, Use of different damage models for simulating impact-driven spallation in metal plates, International Journal of Impact Engineering, 30(3), 275-301 and references therein. 4. Mader, C., Numerical Modeling of Detonations, University of California Press, 1979. 5.

The Revolution in Experimental and Observational Science

Description of natural phenomena Last few hundred years Theoretical Science Newton [s Laws, Maxwell [s Equations Last few decades Computational Science Simulation of complex phenomena Today Data-Intensive Science Scientists overwhelmed with data sets from many different sources Data captured by instruments


phenomena. A previously developed interfacial delamination model is being adapted for this problem, and integration of these efforts will provide the pathway to the TBC design code. Research Objectives The main objective of NOMELT is to develop a code that facilitates the more aggressive

Effects of Temperature and Particle Size on Deposition in

barrier coating (TBC) spallation duringa4haccelerated test. In the second series of tests, particle deposition rate was found to decrease with decreasing gas temperature. The threshold gas temperature for deposition was approximately 960°C. In the third and fourth test series, impingement cooling was applied to the back side of the target coupon


crater size, and spallation were affected.3 In this study, the validity of plane strain computations of a continuous shaped-charge jet obliquely impacting a target is examined. The problem to be studied is the penetration and perforation of.a 12.7-mm steel plate by a continuous, copper, shaped-charge jet at an

Particle-based modeling of hypervelocity impact and

phenomena relatively well, but they are based on continuum theory which is not ideally suited for modeling fracture and failure in materials and for representing the discontinuities in shock waves responsible for many HVI phenomena. In this paper we present a completely different approach to simulating HVI by using a discrete method.

A combined molecular dynamics and finite element method

One problem is that a pres-sure wave reflected from the boundaries of the MD computational cell can interfere with the processes in the ablation region and hinder interpretation of the results of the simulation. Recently we developed a simple and computationally efficient approach for simulating the non-reflecting propagation of a pres-

NASA-CR-195152 ///-/B c'/Z.

FINAL REPORT submitted to L,a National Aeronautics and Space Administration Lyndon B. Johnson Space Center Space Science Branch ATTN: Eric L. Christiansen Houston, TX 77058 for research entitled

Orientation and Rate Dependence of Wave Propagation in

May 12, 2020 to study the phenomena. In particular, molecular dy-namics simulation can reveal the processes and the mechanisms involved at the atomistic level.[6−9] Ho-lian and co-workers successfully reported the results of MD calculation of shock wave propagation in poly-crystalline iron[10] and also presented the atomistic

Mn+1AX Phonon Density of States: Ti AlC and Ti Simulation and

To overcome this problem and investigate the atomic level phenomena of Ti3SiC2 and Ti3AlC2, the Fig. 1 Average crystal structure of Ti3SiC2. Substituting Si for Al yields the average crystal structure of Ti3AlC2. approach taken in this research was to simulate both systems using DFT lattice dynamics, and, DFT-MD

general problem of how the solar system was assembled. Impact cratering, unlike nearly any other geophysical phenomenon, involves a very broad range of mass, length, and time scales, each with a rich physics. This makes any analytiœdl theoretical description of the process approximate in one regard or another. The advent of economical, high-

energy protons - arXiv

1. spallation is the process in which only one heavy fragment with a mass close to the target mass, AT, is formed (a special case of spallation is the so-called deep spallation where M = 1 but A ∼ 2 3 AT); 2. fission is the process in which M = 2 and A is around AT/2; 3. multifragmentation is the process where M > 2 and A < 50.

Final Report - Drexel University

compared with available analytical solutions of the ricochet problem available in the literature. Equation of State (EOS) is the key element in computer-based and analytical studies of hypervelocity impact phenomena. The majority of these is based on the Gruneisen assumption and Mie-Gruneisen EOS.

Introduction: Laser Ablation of Molecular Substrates

lie hidden highly complex phenomena, entailing a number of unique features: a large number of mol-ecules are excited, ultrafast heating rates are at-tained, high-amplitude stress waves are induced, and the physical state of the substrate may go through a rather unusual transition. All these occur in paral-lel on a very fast time scale.


3. Problem description 3.1 Ablation Process Ablators can be basically divided in two major groups: pure and composite materials as described by Braga (2002) and Kanevce (1999). Pure ablative materials are mainly characterized by no phase changes at the surface until it reaches the ablation temperature.

Accelerator Physics Overview - Spallation Neutron Source

Chinese Spallation Neutron Source European Spallation Source Facility for Rare Isotope Beams GANIL U.S. Spallation Neutron Source at ORNL TRIUMF Ta rg e t D a te Ta sk Pro g re ss (a s o f Ap r 2 5 , 2 0 1 3 ) Ma y 3 , 2 0 1 0 W o rksh o p a t SN S

Assessment of Turbulence Models for Heavy Liquid Metals in

and have to dissipate large quantities of heat. It is fundamental to have a tool capable of simulating the critical phenomena occurring. The physics associated with the spallation can be simulated with the help of a Montecarlo code that, given the complexity of the resulting heat distributions, has to

Large-Scale Simulation of Beam Dynamics in High Intensity Ion

provement in simulation capability, in terms of problem size and speed of execution, compared with typical two-dimensional serial simulations. Specific examples will be presented, including simulation of the spallation neutron source (SNS) linac and the Low Energy Demonstrator Ac-celerator (LEDA) beam halo experiment. 1 INTRODUCTION


ment code for simulating short-time shock-wave propa- phenomena of mound formation, spallation, and surface sible to analyze the problem for a much longer

The Limits of Simulating Gas Giant Entry at True Gas

suited for simulating entry for planned missions to Uranus and Saturn. Expansion tube experiments using the true gas compo-sition will also allow the flow phenomena experienced during an actual gas giant entry to be studied, something that was not able to be done when the Galileo probe was designed, which