Granular Morphologies: Programming Material Behaviour with Designed Aggregates

Abstract

What if designers were to become more than specifiers of materials, and actually defined the composition of the matter they work with? Granular materials, or rather ‘designed aggregates’, as introduced here by Karola Dierichs, architect and researcher at the Institute for Computational Design (ICD), and Guest‐Editor Achim Menges, are one distinct group of materials that can be considered ‘designed matter’. What makes designed granular systems particularly interesting is that they do not obtain a final structure with preset properties. Instead, their elemental constituents remain unfixed, allowing them to continuously and physically recompute structural and spatial characteristics, challenging our very conception of design.

Origin of geometric cohesion in non-convex granular materials: interplay between interdigitation and rotational constraints enhancing frictional stability

“…The jamming transition -the change between these two phases -as well as the stability of the jammed state have therefore been extensively studied over the past decades across many domains. Recently, a new family of granular systems composed of non-convex grains, also called metagrains, has emerged [1][2][3]. These systems make it possible to form extremely stable jammed structures while remaining easy to manipulate in their fluid phase.…”

“…These particles consist of elongated, straight, rigid branches radiating from a central core. They were popularized by the seminal work of K. Dierichs and A. Menges, who demonstrated the potential of metagrains for constructing human-scale architectural structures [1,2,16]. More quantitative studies have since investigated these systems, characterizing pile stability [17,18], their resistance to external loading [17], vibrations [19,20], and shear deformation [21,22].…”

Secondary flow in ensembles of non-convex granular particles under shear

“…Stiffening sets in at ρ ≈ 6.7. In addition to fundamental interest in such particle shapes, stars and hexapods may be of practical value in granular architecture [39][40][41][42]. We shear ensembles of spatial crosses (Fig.…”

Stress propagation in locally loaded packings of disks and pentagons

“…Yet isolating crucial shape differences between spherical grains and other a Department of Physics, Duke University, Durham, North Carolina 27708, USA. E-shapes is necessary for characterizing the mechanics and dynamics of real granular materials found in geophysical systems [13][14][15] , processed in pharmaceutical and agricultural industries, and utilized in civil engineering 16 . In the past two decades, advances in technologies that can mass-produce grains of well defined shapes (e.g., 3D printing 17,18 and laser cutting 19 ) and computational tools that can efficiently model aspherical grains [20][21][22][23] have enabled numerous studies of granular materials with nonspherical grains.…”