Perspective: Evolutionary design of granular media and block copolymer patterns

Jaeger, Heinrich M.; Pablo, Juan J. de

doi:10.1063/1.4948270

Cited by 35 publications

(27 citation statements)

References 69 publications

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“…In a typical optimization of this type, more than a dozen material and geometry parameters are being tuned. 8,9,18 In Figure 3, we show the simulated evolution during annealing from initially disordered domains to a final stripe configuration that is highly ordered and aligned with the markers in the substrate. In the top panel, we plot the performance of black box CMA-ES for a case where the markers were placed a distance corresponding to three times the inherent domain spacing of the copolymer blocks.…”

Section: From Statistical Mechanics To Automated Designmentioning

confidence: 99%

“…The data show the evolution of the objective function during optimization as a function of the number of iterations, or generations. (a) Standard, black box covariance matrix adaptation evolution strategy (CMA-ES) with substrate markers, indicated by slight vertical protrusions in the gray substrate and placed a distance of three domain repeat spacings apart 18. (b) Advanced evolution strategy using problem-specific ( )ρ λ | i xinEquation 4, with substrate markers of adjustable width w placed a distance 6 m of six domain repeat spacings apart.…”

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confidence: 99%

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Bioinspired nonequilibrium search for novel materials

Murugan

Jaeger

2019

MRS Bull.

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Section: From Statistical Mechanics To Automated Designmentioning

confidence: 99%

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confidence: 99%

Bioinspired nonequilibrium search for novel materials

Murugan

Jaeger

2019

MRS Bull.

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“…The CMAES algorithm has been used in prior work to find inverse solutions to various problems fast and efficiently. 57,74,75,77,85–87 A description of the algorithm can be found in previous work. 16,57,74,75,85 Here we use the method to find the set of model parameters that lead to the self-assembly in simulation of a BCP density profile that when transformed into a scattered intensity pattern has the best match with an experimental data set.…”

Section: Methodsmentioning

confidence: 99%

Optimizing self-consistent field theory block copolymer models with X-ray metrology

Hannon

Sunday

Bowen

et al. 2018

Mol. Syst. Des. Eng.

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A block copolymer self-consistent field theory (SCFT) model is used for direct analysis of experimental X-ray scattering data obtained from thin films of polystyrene--poly(methyl methacrylate) (PS--PMMA) made from directed self-assembly. In a departure from traditional approaches, which reconstruct the real space structure using simple geometric shapes, we build on recent work that has relied on physics-based models to determine shape profiles and extract thermodynamic processing information from the scattering data. More specifically, an SCFT model, coupled to a covariance matrix adaptation evolutionary strategy (CMAES), is used to find the set of simulation parameters for the model that best reproduces the scattering data. The SCFT model is detailed enough to capture the essential physics of the copolymer self-assembly, but sufficiently simple to rapidly produce structure profiles needed for interpreting the scattering data. The ability of the model to produce a matching scattering profile is assessed, and several improvements are proposed in order to more accurately recreate the experimental observations. The predicted parameters are compared to those extracted from model fits additional experimental methods and with predicted parameters from direct particle-based simulations of the same model, which incorporate the effects of fluctuations. The Flory-Huggins interaction parameter for PS--PMMA is found to be in agreement with reported ranges for this material. These results serve to strengthen the case for relying on physics-based models for direct analysis of scattering and light signal based experiments.

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“…Dry friction between relatively sliding bodies can dissipate energy and produce hysteresis between the loading and unloading force–displacement curves. Therefore, a granular material, composed of many solid particles interacting with contact and friction forces, is considered as a promising option for energy dissipation . This has been experimentally confirmed in soft robots composed of jammed particles, propagation of earthquakes, waves, etc.…”

Section: Introductionmentioning

confidence: 96%

Programmable Granular Metamaterials for Reusable Energy Absorption

Zhao

Jin

2019

Adv Funct Materials

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Designing metamaterials with programmable features has emerged as a promising pathway for reusable energy absorption. While the current designs of reusable energy absorbers mainly exploit mechanical instability of flexible beams, here is created a new kind of metamaterial for reusable and programmable energy absorption by integrating rigid granular materials and compliant stretchable components. In each unit cell of the metamaterial, the stretchable components connect the granular particles to maintain the integrity and control the deformation pattern of the material. When the metamaterial is subjected to an external load, the input energy is partially trapped as elastic energy in the stretchable components, and partially dissipated by friction between the granular particles, forming hysteresis between the loading and unloading force-displacement curves. Through tuning the structural design of the metamaterial, the pretension and stiffness of the stretchable components, and the size of and friction between the particles, a vast design space is achieved to program the mechanical behavior of the metamaterial, such as the load-displacement curve, the multistability, and the amount of energy dissipation. Experimental impact tests on a thin glass panel confirm energy-absorbing capability of the proposed metamaterial. This design strategy opens a new avenue for creating reusable energy-absorbing metamaterials.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201901258. and a long working distance. Most commercial energy-absorbing products adopt plastic deformation or fragmentation of foams, [3] metals, [4] and ceramics, [5] to gain the desired hysteresis behavior, and introduce artificial defects, such as prefolding of origami, [6][7][8] to control the deformation mode. In the products with plastic deformation or fragmentation, dislocations and bond breakage occur at the molecule level, and a large amount of energy can be absorbed. However, they are only for one-time usage, since the materials are permanently damaged.In order to overcome the shortcoming of one-time usage, reusable energyabsorbing materials have been proposed by developing damage-tolerant micro [9] or nano lattices, [5] architectured composite materials, [10,11] and mechanical metamaterials. [12][13][14][15] Mechanical metamaterials are materials with microstructures, which give rise to unique mechanical properties that are otherwise hard to achieve. [12][13][14] By designing the microstructures, researchers have developed energy-absorbing metamaterials mainly through exploiting mechanical instability of the deformable microstructures. [16][17][18][19][20] A well-utilized strategy to achieve reusability is making use of bistability of curved beams and tilted straight beams under buckling, [21][22][23] since during the working process, deformation of these constituent structures is elastic. Although the energyabsorbing capability of these metamaterials is currently not comparable to those...

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Perspective: Evolutionary design of granular media and block copolymer patterns

Cited by 35 publications

References 69 publications

Bioinspired nonequilibrium search for novel materials

Bioinspired nonequilibrium search for novel materials

Optimizing self-consistent field theory block copolymer models with X-ray metrology

Programmable Granular Metamaterials for Reusable Energy Absorption

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