A contact dynamics code implementation for the simulation of asteroid evolution and regolith in the asteroid environment

Sánchez, Paul; Renouf, Mathieu; Azéma, Émilien; Mozul, Rémy; Dubois, Frédéric

doi:10.1016/j.icarus.2021.114441

Cited by 13 publications

(6 citation statements)

References 77 publications

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“…The accretion process for the 10400-particle assembly is exhibited in Figure 11(a). We obtain a similar pattern as presented by Sánchez et al (2021).…”

Section: Simulation Of Self-gravitating Aggregationsupporting

confidence: 84%

“…The study of nonspherical DEM in planetary science is just getting started. Sánchez et al (2021) developed a numerical implementation of nonspherical particles in the open-source software LMGG90. The amount of nonspherical particles used in the simulations reached 8000; therefore, the impulse-based contact model is adopted to promote the computing speed, yet it cannot accurately capture the particle deformation in dense regimes.…”

Section: Introductionmentioning

confidence: 99%

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Accelerating Polyhedral Discrete Element Method with CUDA

Wen,

Zeng

2023

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This paper presents an efficient CUDA-based implementation of a nonspherical discrete element method where irregular particles are described by using polyhedrons. Two strategies are employed to exploit the parallelism of the numerical method. One is to perform contact detection based on the contact pair level instead of the traditional particle level. The second is to reduce the computational burden of each kernel function by allocating thread blocks reasonably. Contact detection between potential contact pairs is the most complicated, time-consuming, and essential process for the polyhedral discrete element method. The linear bounding volume hierarchies are introduced to fix this issue. The hierarchies of the bounding volume tree are organized in a spatially coherent way. Such a structure can minimize branch divergence and is very suitable for parallel implementation with GPU. Two numerical examples are presented to show the performance of the code. It is found from the scenario of two sphere collision that improving the mesh resolution of polyhedral particles can reduce the computational error while slowing down the computational speed correspondingly. A trade-off must be made between accuracy and efficiency. The other example of self-gravitating aggregation demonstrates the code is convergent, stable, and highly efficient. Particularly, with a mainstream GPU, the proposed method easily performs hundreds of times faster than the serial CPU code that does the same function.

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“…The accretion process for the 10400-particle assembly is exhibited in Figure 11(a). We obtain a similar pattern as presented by Sánchez et al (2021).…”

Section: Simulation Of Self-gravitating Aggregationsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Accelerating Polyhedral Discrete Element Method with CUDA

Wen,

Zeng

2023

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“…[37]. We used the platform LMGC90, which is a multipurpose software developed in Montpellier, capable of modeling a collection of deformable or undeformable particles of various shapes [38,39].…”

Section: A Numerical Methodsmentioning

confidence: 99%

Nonlinear effect of grain elongation on the flow rate in silo discharge

Bignon,

Renouf,

Sicard

et al. 2023

Phys. Rev. E

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By means of two-dimensional numerical simulations based on contact dynamics, we present a systematic analysis of the joint effects of grain shape (i.e., grain elongation) and system size on silo discharge for increasing orifice sizes D. Grains are rounded-cap rectangles whose aspect ratio are varied from 1 (disks) to 7. In order to clearly isolate the effect of grain shape, the mass of the grains is keeping constant as well as the condition of the discharge by reintroducing the exiting grains at the top of the silo. In order to quantify the possible size effects, the thickness W of the silos is varied from 7 to 70 grains diameter, while keeping the silos aspect ratio always equal to 2. We find that, as long as size effects are negligible, the flow rate Q increases as a Beverloo-like function with D, also for the most elongated grains. In contrast, the effects of grain elongation on the flow rate depend on orifice size. For small normalized orifice sizes, the flow rate is nearly independent with grain elongation. For intermediate normalized orifice sizes the flow rate first increases with grain elongation up to a maximum value that depends on the normalized size of the orifice and saturates as the grains become more elongated. For larger normalized orifice size, the flow rate is an increasing function of grains' aspect ratio. Velocity profiles and packing fraction profiles close to the orifice turn out to be self-similar for all grain shapes and for the whole range of orifice and system sizes studied. Following the methodology introduced by Janda et al. [Phys. Rev. Lett. 108, 248001 (2012)], we explain the nonlinear variation of Q with grain elongation, and for all orifice sizes, from compensation mechanisms between the velocity and packing fraction measured at the center of the orifice. Finally, an equation to predict the evolution of Q as a function of the aspect ratio of the grains is deduced.

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“…Most DEM codes used in the context of small solar system bodies have relied on spherical particles for the simplicity and computational efficiency they afford. That said, some N-body DEM codes have included nonspherical particles of various construction, with most examples using either polyellipsoids (Roig et al 2003) or polyhedra (Ferrari & Tanga 2020;Sánchez et al 2021). Due to the complexity of applying contact physics and interparticle gravity to irregular shapes, these efforts have historically had to compromise on the fidelity of the physics model, the number of particles included in simulations, or both.…”

Section: Importance Of Particle Shape In Granular Mediamentioning

confidence: 99%

“…And while this method uses a tree to reduce the cost of gravity calculations, it is confined to a single GPU, ultimately leading to memory limitations on overall resolution. Sánchez et al (2021) also allowed for nonspherical, self-gravitating particles but used a nonsmooth contact dynamics method rather than an SSDEM approach and likewise omitted gravitational torques. Alternately, there are a number of existing DEM codes that are capable of modeling the interaction of hundreds of thousands or even millions of nonspherical particles with full SSDEM contacts (Zhao et al 2006;Knuth et al 2012;Longmore et al 2013;Nguyen & Plimpton 2019).…”

Section: Importance Of Particle Shape In Granular Mediamentioning

confidence: 99%

An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics

Marohnic,

DeMartini,

Richardson

et al. 2023

Planet. Sci. J.

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We present an approach for the inclusion of nonspherical constituents in high-resolution N-body discrete element method (DEM) simulations. We use aggregates composed of bonded spheres to model nonspherical components. Though the method may be applied more generally, we detail our implementation in the existing N-body code pkdgrav. It has long been acknowledged that nonspherical grains confer additional shear strength and resistance to flow when compared with spheres. As a result, we expect that rubble-pile asteroids will also exhibit these properties and may behave differently than comparable rubble piles composed of idealized spheres. Since spherical particles avoid some significant technical challenges, most DEM gravity codes have used only spherical particles or have been confined to relatively low resolutions. We also discuss the work that has gone into improving performance with nonspherical grains, building on pkdgrav's existing leading-edge computational efficiency among DEM gravity codes. This allows for the addition of nonspherical shapes while maintaining the efficiencies afforded by pkdgrav's tree implementation and parallelization. As a test, we simulated the gravitational collapse of 25,000 nonspherical bodies in parallel. In this case, the efficiency improvements allowed for an increase in speed by nearly a factor of 3 when compared with the naive implementation. Without these enhancements, large runs with nonspherical components would remain prohibitively expensive. Finally, we present the results of several small-scale tests: spin-up due to the YORP effect, tidal encounters, and the Brazil nut effect. In all cases, we find that the inclusion of nonspherical constituents has a measurable impact on simulation outcomes.

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A contact dynamics code implementation for the simulation of asteroid evolution and regolith in the asteroid environment

Cited by 13 publications

References 77 publications

Accelerating Polyhedral Discrete Element Method with CUDA

Accelerating Polyhedral Discrete Element Method with CUDA

Nonlinear effect of grain elongation on the flow rate in silo discharge

An Efficient Numerical Approach to Modeling the Effects of Particle Shape on Rubble-pile Dynamics

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