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What is shape? Characterizing particle morphology with genetic algorithms and deep generative models

Buarque de Macedo, R. and Monfared, S. and Karapiperis, K. and Andrade, J. E. (2023) What is shape? Characterizing particle morphology with genetic algorithms and deep generative models. Granular Matter, 25 (1). Art. No. 2. ISSN 1434-5021. doi:10.1007/s10035-022-01282-y.

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Engineered granular materials have gained considerable interest in recent years. For this substance, the primary design variable is grain shape. Optimizing grain form to achieve a macroscopic property is difficult due to the infinite-dimensional function space particle shape inhabits. Nonetheless, by parameterizing morphology the dimension of the problem can be reduced. In this work, we study the effects of both intuitive and machine-picked shape descriptors on granular material properties. First, we investigate the effect of classical shape descriptors (roundness, convexity, and aspect ratio) on packing fraction ϕ and coordination number Z. We use a genetic algorithm to generate a uniform sampling of shapes across these three shape parameters. The shapes are then simulated in the level set discrete element method. We discover that both ϕ and Z decrease with decreasing convexity, and Z increases with decreasing aspect ratio across the large sampling of morphologies—including among highly non-convex grains not commonly found in nature. Further, we find that subtle changes in mesoscopic properties can be attributed to a continuum of geometric phenomena, including tessellation, hexagonal packing, nematic order and arching. Nonetheless, such descriptors alone can not entirely describe a shape. Thus, we find a set of 20 descriptors which uniquely define a morphology via deep generative models. We show how two of these machine-derived parameters affect ϕ and Z. This methodology can be leveraged for topology optimization of granular materials, with applications ranging from robotic grippers to materials with tunable mechanical properties.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access
Buarque de Macedo, R.0000-0002-2218-4117
Monfared, S.0000-0002-7629-7977
Karapiperis, K.0000-0002-6796-8900
Andrade, J. E.0000-0003-3741-0364
Additional Information:This work was supported by Army grant W911NF-19-1-0245. Part of a collection: Physics-informed artificial intelligence for granular matter
Funding AgencyGrant Number
Army Research Office (ARO)W911NF-19-1-0245
Issue or Number:1
Record Number:CaltechAUTHORS:20221121-712406200.7
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117942
Deposited By: Research Services Depository
Deposited On:01 Dec 2022 18:21
Last Modified:01 Dec 2022 18:21

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