Numerical Studies of Explosive Welding by SPH

2007 ◽  
Vol 566 ◽  
pp. 61-64 ◽  
Author(s):  
Katsumi Tanaka
Keyword(s):  
Explosive Welding ◽  
High Speed ◽  
Weld Interface ◽  
Oblique Impact ◽  
Major Mechanism ◽  
Particle Hydrodynamics ◽  
Detached Shock Wave ◽  
Smoothed Particle ◽  
Wavy Interface ◽  
Karman Vortex

A particular characteristic of an explosively produced weld is that the profile of the weld interface often has a regular wavy appearance. An effect of detached shock wave and jetting on the metal interface of explosive welding has been shown by SPH (Smoothed particle hydrodynamics). Numerical results show wavy interface which is observed in several experiments. High speed jet between interface and Karman vortex after oblique impact of a flyer plate to a parent plate were major mechanism of explosive welding.

scholarly journals Impact and Fire Modeling Considerations Employing SPH Coupling to a Dilute Spray Fire Code

2009 ◽  
Author(s):  
Alexander L. Brown
Keyword(s):  
High Speed ◽  
Good Method ◽  
Predictive Tool ◽  
Surface Deposition ◽  
Impact Surface ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Model Inadequacy ◽  
The Impact ◽  
Adequate Method

Transportation accidents and the subsequent fire present a concern. Particularly energetic accidents like an aircraft impact or a high speed highway accident can be quite violent. We would like to develop and maintain a capability at Sandia National Laboratories to model these very challenging events. We have identified Smoothed Particle Hydrodynamics (SPH) as a good method to employ for the impact dynamics of the fluid for severe impacts. SPH is capable of modeling viscous and inertial effects for these impacts for short times. We have also identified our fire code Lagrangian/Eulerian (L/E) particle capability as an adequate method for fuel transport and spray modeling. A fire code can also model the subsequent fire for a fuel impact. Surface deposition of the liquid may also be acceptably predicted with the same code. These two methods (SPH and L/E) typically employ complimentary length and timescales for the calculation, and are potentially suited for coupling given adequate attention to relevant details. Length and timescale interactions are important considerations when joining the two capabilities. Additionally, there are physical model inadequacy considerations that contribute to the accuracy of the methodology. These models and methods are presented and evaluated. Some of these concerns are detailed for a verification type scenario used to show the work in progress of this coupling capability. The importance of validation methods and their appropriate application to the genesis of this class of predictive tool are also discussed.

Calculation of oblique impact and fracture of tungsten cubes using smoothed particle hydrodynamics

1995 ◽  
Vol 17 (4-6) ◽  
pp. 661-672 ◽  
Author(s):  
P.W. Randles ◽  
T.C. Carney ◽  
L.D. Libersky ◽  
J.D. Renick ◽  
A.G. Petschek
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Oblique Impact ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

The Prediction of High-Speed Landslide Movement and Simulation of Generated Impulsive Wave by SPH Method

2011 ◽  
Vol 378-379 ◽  
pp. 418-422
Author(s):  
Ji Lun Miao ◽  
Jing Qiu Chen ◽  
Cen Wen
Keyword(s):  
High Speed ◽  
Limit Equilibrium ◽  
Soil Mass ◽  
Equilibrium Analysis ◽  
Sph Method ◽  
Limit Equilibrium Analysis ◽  
Particle Hydrodynamics ◽  
Sample Test ◽  
Smoothed Particle ◽  
Landslide Movement

A sliding block model is developed for predicting the runout of high-speed landslides, which couple with SPH method (Smoothed Particle Hydrodynamics) to simulate impulse wave. This model adopts the limit equilibrium analysis approach to simulate the whole travel process of the soil mass from the onset of the landslide. The submarine landslide produces highly unsteady and rapidly varied flows, so it was very complicated by fixed grid numerical simulations. The SPH method is a meshfree particle-based Lagrangian method. A sample test is given which shows the impulsive waves generated by high-speed landslide can be reproduced well.

Simulation and experimental study on lubrication of high-speed reducer of electric vehicle

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fuchun Jia ◽  
Yulong Lei ◽  
Xianghuan Liu ◽  
Yao Fu ◽  
Jianlong Hu
Keyword(s):  
Flow Field ◽  
Electric Vehicle ◽  
High Speed ◽  
Content Type ◽  
Speed Reducer ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Novel Method ◽  
Set Up ◽  
Volume Method

Purpose The lubrication of the high-speed reducer of an electric vehicle is investigated. The specific contents include visualization of the flow field inside reducer, lubrication evaluation of bearings and efficiency experiment. Design/methodology/approach The flow field inside reducer at five working conditions: straight, uphill, downhill, left lean and right lean is simulated by smoothed particle hydrodynamics (SPH). According to the instantaneous number of particles through bearings, the lubrication states of bearings are evaluated. The test platform is set up to measure the efficiency of the reducer. Findings The flow field inside the reducer is obtained, the lubrication of bearings needs to be improved, the efficiency of the electric vehicle reducer meets the requirement. Originality/value The SPH method is used to simulate lubrication instead of using the traditional grid-based finite volume method. A novel method to evaluate the lubrication of bearings is proposed. The method and conclusions can guide electric vehicle reducer design.

Specific features of mathematical modeling of ceramic plates destruction under the influence of high-speed impactors

2021 ◽  
Author(s):  
A.V. Petukov ◽  
K.A. Grin
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Plate Thickness ◽  
Vertex Angle ◽  
Courant Number ◽  
Sph Method ◽  
Viscosity Coefficients ◽  
Computational Mesh ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

The paper examines the issues of mathematical modeling of ceramic armor panels’ penetration by high-speed cylindrical impactors. By means of the LS-DYNA software package, a corresponding numerical simulation methodology was developed by combining a chosen method, adjusted computational mesh cells size, appropriate Courant number, and values of linear and quadratic pseudo-viscosity coefficients. The results compared with experimental data show that Lagrangian and Eulerian numerical methods, unlike the SPH method (Smoothed Particle Hydrodynamics), improperly reproduce the process of the shock wave disintegration into an elastic precursor and a plastic wave. In addition, the common size of conical fractions dislodging from the ceramic plates was determined and the influence of the scale effect on the ceramics damage patterns was shown: an increase in the absolute value of the plate thickness leads to the increase in the dislodging cone semi-vertex angle.

Viscous Flow Past a Circular Cylinder Below a Free Surface

2014 ◽  
Author(s):  
Benjamin Bouscasse ◽  
Andrea Colagrossi ◽  
Salvatore Marrone ◽  
Antonio Souto-Iglesias
Keyword(s):  
Free Surface ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Mixing Processes ◽  
Surface Evolution ◽  
Flow Past ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Karman Vortex ◽  
Drag And Lift

Flow past a circular cylinder close to a free surface at low Reynolds and large Froude numbers is investigated numerically using the Smoothed Particle Hydrodynamics model. This meshless method allows for a non-diffusive computation of the free surface evolution, even while breaking and fragmentation may occur. The distance of the cylinder to the free surface, submergence, is varied in order to investigate the detached flow patterns dependence with this factor. Vorticity shed by the cylinder, vortex generation due to free surface breaking, mixing processes, and drag and lift coefficients behavior are discussed. It has been found that, for small submergences, the classical Von Karman vortex shedding from the cylinder does not take place. In turn, moderate vortex shedding occurs, departing not from the cylinder but from vorticity generated at the free surface. This shedding takes places simultaneously with the transport of free surface fluid elements into the bulk of the fluid. It has been also found that for even smaller depth ratios, a vorticity layer remains spatially localized between the cylinder and the free surface, and a stagnation recirculating area develops behind the cylinder. Results are compared with literature finding reasonable qualitatively agreement with experimental works conducted with similar geometrical configuration but larger Reynolds number.

scholarly journals Similarity and dissimilarity of joint interface morphology in magnetic pulse welded Al/Cu and Al/Ni plates

2020 ◽  
Vol 326 ◽  
pp. 08004
Author(s):  
Shingo Kimura ◽  
Shinji Muraishi ◽  
Shinji Kumai
Keyword(s):  
Intermediate Phase ◽  
Density Difference ◽  
Joint Interface ◽  
Magnetic Pulse ◽  
Interface Morphology ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Wavy Interface ◽  
The Difference ◽  
Pulse Welding

A characteristic wavy morphology often appears at the joint interface of magnetic pulse welding (MPW), and an intermediate layer is formed in some metal combinations. It has been known that the wavy morphology changes mainly depend on the density difference between the metals. A sinusoidal wavy interface is formed for the combination of similar metals (Al/Al, Cu/Cu) and that of dissimilar metals having almost the same density (Cu/Ni). In contrast, a trigger-like wavy interface is formed for the combination having a large density difference (Al/Cu, Al/Fe). The difference in strength (hardness) of the solid metal is also assumed to affect the wavy interface morphology. In the present study, two metal combinations (Al/Cu and Al/Ni) were subjected to the MPW to elucidate the effect of hardness difference, since Cu and Ni have almost the same density, but different hardness. Both the MPWed Al/Cu and Al/Ni joints showed a trigger-like wave interface. The wave size (wave-height and wavelength) of Al/Ni was smaller than that of Al/Cu. In Al/Ni, the distribution of intermediate phase was more continuous tracing the outline of the wave. The numerical simulation of the wave formation process was performed using the Smoothed Particle Hydrodynamics (SPH) method. It was revealed that the extent of metal jet penetration into the metal in the process of joining behind the collision point was weaker in Ni than in Cu. This is considered to be due to the larger deformation resistivity of Ni, which is harder than that of Cu.

scholarly journals A Fast and Practical Method for Animating Particle-Based Viscoelastic Fluids

2011 ◽  
Vol 10 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Kenji Takamatsu ◽  
Takashi Kanai
Keyword(s):  
High Speed ◽  
Shape Matching ◽  
Viscoelastic Fluids ◽  
Elastic Solid ◽  
Practical Method ◽  
Linear Interpolation ◽  
Particle Hydrodynamics ◽  
Speed Performance ◽  
Smoothed Particle ◽  
Real Time Applications

This paper proposes a practical technique for fast animation of materials such as viscoelastic fluids. A fast animation of such materials is desperately desirable especially for real-time applications such as games. We compute the behavior of viscoelastic fluids approximately instead of the exact simulation by combining two well-established approaches, Smoothed- Particle Hydrodynamics and Shape Matching. This enables fast and stable computations. A combination is done by a simple linear interpolation of velocities. A variety of materials between a fluid and an elastic solid can be represented by changing only a parameter of linear interpolation. We also propose how to bring our approximate method closer to the actual motions of viscoelastic fluids including merging or splitting of objects. We demonstrate a high-speed performance of our method with presenting several interesting results.

Sign in / Sign up

Export Citation Format

Share Document