Link between packing morphology and the distribution of contact forces and stresses in packings of highly nonconvex particles

Conzelmann, Nicholas A.; Penn, Alexander; Partl, Manfred N.; Clemens, Frank; Poulikakos, Lily D.; Müller, Christoph R.

doi:10.1103/physreve.102.062902

Cited by 13 publications

(5 citation statements)

References 59 publications

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“…The 'sphericity' of the particles was used as a variable parameter. Their results show-among other things-that the distribution of contact forces of 3D packings in the normal direction of compression becomes increasingly heterogeneous if particle 'sphericity' is decreased; whereas in 2D packings this distribution is not affected by the particle 'sphericity' [117]. This project clearly establishes a particle model with variable parameters for the particles' 'sphericity' and simulations are deployed.…”

Section: Designed Granular Materials In Physicsmentioning

confidence: 90%

Designing architectural materials: from granular form to functional granular material

Dierichs

Menges

2021

Bioinspir. Biomim.

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Designed granular materials are a novel class of architectural material system. Following one of the key paradigms of designed matter, material form and material function are closely interrelated in these systems. In this context, the article aims to contribute a parametric particle design model as an interface for this interrelation. A granular material is understood as an aggregation of large numbers of individual particles between which only short-range repulsive contact forces are acting. Granular materials are highly pertinent material systems for architecture. Due to the fact that they can act both as a solid and a liquid, they can be recycled and reconfigured multiple times and are thus highly sustainable. Designed granular materials have the added potential that the function of the granular material can be calibrated through the definition of the particles’ form. Research on the design of granular materials in architecture is nascent. In physics they have been explored mainly with respect to different particle shapes. However, no coherent parametric particle design model of designed particle shapes for granular material systems in architecture has yet been established which considers both fabrication constraints and simulation requirements. The parametric particle design model proposed in this article has been based on a design system which has been developed through feasibility tests and simulations conducted in research and teaching. Based on this design system the parametric particle design model is developed integrating both fabrication constraints for architecture-scale particle systems and the geometric requirements of established simulation methods for granular materials. Initially the design system and related feasibility tests are presented. The parametric particle design model resulting from that is then described in detail. Directions of further research are discussed especially with respect to the integration of the parametric particle design model in ‘inverse’ design methods.

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Section: Designed Granular Materials In Physicsmentioning

confidence: 90%

Designing architectural materials: from granular form to functional granular material

Dierichs

Menges

2021

Bioinspir. Biomim.

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“…Even though the simulation of non-convex granular assemblies is in rapid development today [17,[63][64][65][66][67][68][69][70], these works also expose some of the limitations of the current modeling approaches. First, the shape of the bodies is sometimes represented using clumped spheres [71], sphero-polyhedra [72,73] or superquadrics [74]. Although these strategies allow one to use well-known methods for convex bodies, the discretization of the shapes may add artificial textures on the surfaces, or they can be rapidly limited when pointy geometries or sharp edges need to be considered.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Bespoke particle shapes in granular matter

2022

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Among granular matter, one type of particle has special properties. Upon being assembled in disordered configurations, these particles interlock, hook, almost braid, and – surprisingly, considering their relatively low packing fractions – show exceptional shear strength.Such is the case of non-convex particles. They have been used in the shapes of tetrapods, ‘L’, ‘Z’, stars, and many others, to protect coasts or build self-standing structures requiring no binders or external supports. Although these structures are often designed without a comprehensive mechanical characterization, they have already demonstrated great potential as highly resistant construction materials. Nevertheless, it is natural to attempt to find the most appropriate non-convex shapes for any given application. Can a particle shape be tuned to obtain a desired mechanical behavior? Although this question cannot be answered yet, current technological, simulation, and experimental developments strongly suggest that it can be resolved in the next decade. A clear understanding of the relationships between particle shapes, mechanical response, and packing properties will be key to providing insights into the behavior of these materials. Such work should stand on 1) robust and general shape descriptors that encode the complexity of non-convex shapes (i.e., the number of arms, the symmetries, and asymmetries of the bodies, the presence of holes, etc.), 2) the analysis of the response of assemblies under different loading conditions, and 3) the disposition and reliability of non-convex shapes to ensure durability. The manufacturing process and an efficient use of resources are additional elements that could further help to optimize particle shape. In the quest of designing bespoke non-convex particles, this paper consolidates the challenges that remain unresolved. It also outlines some routes to explore based on the latest developments in technology and research.

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“…In the absence of physio-chemical cohesion, granular ensembles composed of non-convex and filament-shaped particles exhibit mechanical properties akin to that of cohesive granular materials. [13][14][15][16][17][18] This ''cohesion'' is derived from the interlocking of the particles due to their inherent morphology and is often called 'geometric cohesion'. 19 Geometric cohesion can be categorized into two classes depending on the mechanism from which it originates.…”

Section: Introductionmentioning

confidence: 99%