scholarly journals Numerical study of mechanisms to minimize failure in a metal with soft backing under plane shock loading

2015 ◽  
Vol 471 (2182) ◽  
pp. 20150285
Author(s):  
A. V. S. Siva Prasad ◽  
Sumit Basu
Keyword(s):  
Numerical Study ◽  
Void Nucleation ◽  
Experimental Studies ◽  
Blast Waves ◽  
Plane Shock ◽  
Metallic Structures ◽  
Free Surfaces ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Plate Geometry

In recent times, several experimental studies have reported improved ballistic penetration resistance and blast survivability of metallic structures to which an external coating of a soft elastomeric material has been applied. This work is aimed at understanding, through numerical simulations on a simple metal/elastomer flat plate geometry subjected to planar blast waves, the detailed mechanics of wave propagation, damage evolution and mitigation in a bilayer system. Void nucleation, growth and coalescence is assumed to be the damaging mechanism in the metal. A meshless technique based on smoothed particle hydrodynamics is used within the framework of large deformation elasto-viscoplasticity in the metal and nonlinear elasticity in the elastomer. We show that the thickness of the elastomer plays an important role in shielding void activity in the metal, by creating a sequence of closely spaced pulses that reflect from the interface and free surfaces to maintain non-tensile or weakly tensile states of stress. Moreover, a fictitious material that is capable of undergoing a transformation to a harder material under pressure is studied that proves to be an ideal candidate for damage mitigation.

scholarly journals A Numerical Study of Fluid Flow in a Vertical Slot Fishway with the Smoothed Particle Hydrodynamics Method

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1928 ◽  
Author(s):  
Gorazd Novak ◽  
Angelantonio Tafuni ◽  
José M. Domínguez ◽  
Matjaž Četina ◽  
Dušan Žagar
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Numerical Study ◽  
Free Surface Flows ◽  
Open Boundary ◽  
Doppler Velocity ◽  
Vertical Slot ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Smoothed Particle Hydrodynamics Method ◽  
Vertical Slot Fishway

Fishways have a great ecological importance as they help mitigate the interruptions of fish migration routes. In the present work, the novel DualSPHysics v4.4 solver, based on the smoothed particle hydrodynamics method (SPH), has been applied to perform three-dimensional (3-D) simulations of water flow in a vertical slot fishway (VSF). The model has been successfully calibrated against published field data of flow velocities that were measured with acoustic Doppler velocity probes. A state-of-the-art algorithm for the treatment of open boundary conditions using buffer layers has been applied to accurately reproduce discharges, water elevations, and average velocity profiles (longitudinal and transverse velocities) within the observed pool of the VSF. Results herein indicate that DualSPHysics can be an accurate tool for modeling turbulent subcritical free surface flows similar to those that occur in VSF. A novel relation between the number of fluid particles and the artificial viscosity coefficient has been formulated with a simple logarithmic fit.

scholarly journals Numerical study of rainstorm influence on parachute airdropping based on the smoothed particle hydrodynamics/arbitrary Lagrangian–Eulerian coupling method

2020 ◽  
Vol 15 ◽  
pp. 155892502091561
Author(s):  
Linbo Yan ◽  
Zhengkai Sun ◽  
Han Cheng
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Wind Field ◽  
Numerical Study ◽  
Great Influence ◽  
Coupling Method ◽  
Influential Factor ◽  
Arbitrary Lagrangian Eulerian ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
And Performance

In order to study the influence of rainstorm on parachute dropping, the smoothed particle hydrodynamics/arbitrary Lagrangian–Eulerian coupling method is proposed. Finite elements are used to describe the continuous material such as fabric and air flow field, and the smoothed particle hydrodynamics particles are used to describe the discrete raindrops. The coupling between different fluid and structure is realized by penalty function. In order to distinguish the most influential factor of rainstorm environment on parachute, the effects of raindrop field and wind field in rainstorm are studied, respectively. It could be found that the raindrop fields with different droplet sizes have little effect on the parachute’s shape, opening shock, and performance according to the comparative analysis, while the vertical wind field has a great influence on parachute’s deceleration performance. The wind field, not the raindrop field, is the most important factor affecting the parachute’s deceleration performance. The method and conclusions in this article could provide some references for parachute design.

A Numerical Study on the Pull-Out Strengths of Anchor Bolts Embedded in Concrete Using the Smoothed Particle Hydrodynamics Method

2016 ◽  
Vol 711 ◽  
pp. 1111-1117 ◽  
Author(s):  
Yoshimi Sonoda
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Failure Modes ◽  
Numerical Study ◽  
Failure Process ◽  
Embedment Depth ◽  
Anchor Bolt ◽  
Pull Out ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Anchor Bolts

The strength of an anchor bolt in concrete structure under pull-out load is usually designed by three possible failure modes such as fracture of anchor bolt, cone failure of concrete and bond failure between anchor bolt and concrete. In general, the design load is considered the smallest load corresponding to the aforementioned failure mechanisms. However, unexpected failure often occurs in the anchorage zone due to the complex failure or the change of failure condition. Therefore, it is important to develop the accurate analysis method of ultimate load bearing capacity of the anchor bolt. In this study, we conducted an analytical study using Adaptive Smoothed Particle Hydrodynamics (ASPH) in order to simulate the failure process of anchorage zone and discussed the effect of embedment depth of anchor bolts on their ultimate strength.

scholarly journals Modelling aerated flows with smoothed particle hydrodynamics

2015 ◽  
Vol 17 (4) ◽  
pp. 493-504 ◽  
Author(s):  
Michael Meister ◽  
Wolfgang Rauch
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Bubble Column ◽  
Numerical Study ◽  
Air Entrainment ◽  
Future Perspective ◽  
Engineering Practice ◽  
Special Focus ◽  
Practical Applications ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Modelling aerated flows is a complex application of computational fluid dynamics (CFD) since the interfaces between air and water change rapidly. In this work, the simulation of aerated flows with the smoothed particle hydrodynamics (SPH) method is investigated with a focus towards the application in engineering practice. To prove the accuracy of the method, the processes of air entrainment and rising air bubbles are studied. Through monitoring the evolution of the bubble contours it is shown that the novel approach of adding artificial repulsion forces at the interface does not alter the dynamics but stabilizes the flow. Building on these fundamental processes we extend the discussion to practical applications with a special focus on forced aeration. Since the employment of a detailed SPH model to practical problems remains out of bounds due to the high computational demand, we propose a combined experimental and numerical study where experimental bubble characteristics are imposed on the numerical simulation. Based on the data of the conducted bubble column experiment, the computational demand is significantly decreased such that the oxygen consumption due to biokinetic processes can be modelled. The future perspective is to apply SPH to urban water systems, e.g., for simulating detailed processes in wastewater treatment and sewer hydraulics.

scholarly journals Application of Multiphase Particle Methods in Atomization and Breakup Regimes of Liquid Jets

2014 ◽  
Author(s):  
Amirsaman Farrokhpanah ◽  
Javad Mostaghimi
Keyword(s):  
Numerical Study ◽  
Particle Methods ◽  
Liquid Jets ◽  
Empirical Correlations ◽  
Good Match ◽  
Sph Method ◽  
Jet Breakup ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Critical Weber Number

Multiphase Smoothed Particle Hydrodynamics (SPH) method has been used to study the jet breakup phenomena. It has been shown that this method is well capable of capturing different jet breakup characteristics. The value obtained for critical Weber number here in transition from dripping to jetting is a very good match to available values in literature. Jet breakup lengths are also agreeing well with several empirical correlations. Successful usage of SPH, as a comparably fast CFD solver, in jet breakup analysis helps in speeding up the numerical study of this phenomenon.

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