[ { "id": "authors:0714q-6pz23", "collection": "authors", "collection_id": "0714q-6pz23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220325-220328812", "type": "monograph", "title": "How to See Hidden Patterns in Metamaterials with Interpretable Machine Learning", "author": [ { "family_name": "Chen", "given_name": "Zhi", "clpid": "Chen-Zhi" }, { "family_name": "Ogren", "given_name": "Alexander", "clpid": "Ogren-Alexander-C" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" }, { "family_name": "Brinson", "given_name": "L. Catherine", "orcid": "0000-0003-2551-1563", "clpid": "Brinson-Lynda-Catherine" }, { "family_name": "Rudin", "given_name": "Cynthia", "orcid": "0000-0003-4283-2780", "clpid": "Rudin-Cynthia" } ], "abstract": "Metamaterials are composite materials with engineered geometrical micro- and meso-structures that can lead to uncommon physical properties, like negative Poisson's ratio or ultra-low shear resistance. Periodic metamaterials are composed of repeating unit-cells, and geometrical patterns within these unit-cells influence the propagation of elastic or acoustic waves and control dispersion. In this work, we develop a new interpretable, multi-resolution machine learning framework for finding patterns in the unit-cells of materials that reveal their dynamic properties. Specifically, we propose two new interpretable representations of metamaterials, called shape-frequency features and unit-cell templates. Machine learning models built using these feature classes can accurately predict dynamic material properties. These feature representations (particularly the unit-cell templates) have a useful property: they can operate on designs of higher resolutions. By learning key coarse scale patterns that can be reliably transferred to finer resolution design space via the shape-frequency features or unit-cell templates, we can almost freely design the fine resolution features of the unit-cell without changing coarse scale physics. Through this multi-resolution approach, we are able to design materials that possess target frequency ranges in which waves are allowed or disallowed to propagate (frequency bandgaps). Our approach yields major benefits: (1) unlike typical machine learning approaches to materials science, our models are interpretable, (2) our approaches leverage multi-resolution properties, and (3) our approach provides design flexibility.", "doi": "10.48550/arXiv.2111.05949", "publisher": "arXiv", "publication_date": "2021-11-10" }, { "id": "authors:frpdx-nqb52", "collection": "authors", "collection_id": "frpdx-nqb52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220325-220332816", "type": "monograph", "title": "Sparse metapiles for shear wave attenuation in half-spaces", "author": [ { "family_name": "Celli", "given_name": "Paolo", "orcid": "0000-0001-7839-7472", "clpid": "Celli-Paolo" }, { "family_name": "Nunzi", "given_name": "Ilaria", "clpid": "Nunzi-Ilaria" }, { "family_name": "Calabrese", "given_name": "Andrea", "clpid": "Calabrese-Andrea" }, { "family_name": "Lenci", "given_name": "Stefano", "orcid": "0000-0003-3154-7896", "clpid": "Lenci-Stefano" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "We show that shear waves traveling towards the surface of a half-space medium can be attenuated via buried one-dimensional arrays of resonators -- here called metapiles -- arranged according to sparse patterns around a site to be isolated. Our focus is on shear waves approaching the surface along a direction perpendicular to the surface itself. First, we illustrate the behavior of metapiles, both experimentally and numerically, using 3D printed resonators embedded in an acrylic plate. Then, via numerical simulations, we extend this idea to the case study of an idealized soil half-space, and elucidate the influence of various design parameters on wave attenuation. Results of this work demonstrate that significant wave attenuation can be achieved by installing sparse resonating piles around a selected site on the free surface of the medium, rather than placing resonators directly underneath that same site. This work might have implications in metamaterial-based wave attenuation applications across scales.", "doi": "10.48550/arXiv.2110.02202", "publisher": "arXiv", "publication_date": "2021-10-05" }, { "id": "authors:ed6ms-7ze27", "collection": "authors", "collection_id": "ed6ms-7ze27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210716-222546164", "type": "monograph", "title": "Tuning acoustic impedance in load-bearing structures", "author": [ { "family_name": "Injeti", "given_name": "Sai Sharan", "orcid": "0000-0003-1941-9752", "clpid": "Injeti-Sai-Sharan" }, { "family_name": "Celli", "given_name": "Paolo", "orcid": "0000-0001-7839-7472", "clpid": "Celli-Paolo" }, { "family_name": "Bhattacharya", "given_name": "Kaushik", "orcid": "0000-0003-2908-5469", "clpid": "Bhattacharya-K" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "Acoustic transparency is the capability of a medium to transmit mechanical waves to adjacent media, without scattering. This characteristic can be achieved by carefully engineering the acoustic impedance of the medium -- a combination of wave speed and density, to match that of the surroundings. Owing to the strong correlation between acoustic wave speed and static stiffness, it is challenging to design acoustically transparent materials in a fluid, while maintaining their high structural rigidity. In this work, we propose a method to design architected lattices with independent control of the elastic wave speed at a chosen frequency, the mass density, and the static stiffness, along a chosen loading direction. We provide a sensitivity analysis to optimize these properties with respect to design parameters of the structure, that include localized masses at specific positions. We demonstrate the method on five different periodic, three dimensional lattices, to calculate bounds on the longitudinal wave speed as a function of their density and stiffness. We then perform experiments on 3-D printed structures, to validate our numerical simulations. The tools developed in this work can be used to design lightweight and stiff materials with optimized acoustic impedance for a plethora of applications, including ultrasound imaging, wave filtering and waveguiding.", "doi": "10.48550/arXiv.2106.10573", "publisher": "arXiv", "publication_date": "2021-06-19" }, { "id": "authors:40rgs-6rb67", "collection": "authors", "collection_id": "40rgs-6rb67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210604-142555952", "type": "monograph", "title": "Visual Vibration Tomography: Estimating Interior Material Properties from Monocular Video", "author": [ { "family_name": "Feng", "given_name": "Berthy T.", "clpid": "Feng-Berthy-T" }, { "family_name": "Ogren", "given_name": "Alexander C.", "clpid": "Ogren-Alexander-C" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" }, { "family_name": "Bouman", "given_name": "Katherine L.", "orcid": "0000-0003-0077-4367", "clpid": "Bouman-K-L" } ], "abstract": "An object's interior material properties, while invisible to the human eye, determine motion observed on its surface. We propose an approach that estimates heterogeneous material properties of an object from a monocular video of its surface vibrations. Specifically, we show how to estimate Young's modulus and density throughout a 3D object with known geometry. Knowledge of how these values change across the object is useful for simulating its motion and characterizing any defects. Traditional non-destructive testing approaches, which often require expensive instruments, generally estimate only homogenized material properties or simply identify the presence of defects. In contrast, our approach leverages monocular video to (1) identify image-space modes from an object's sub-pixel motion, and (2) directly infer spatially-varying Young's modulus and density values from the observed modes. We demonstrate our approach on both simulated and real videos.", "doi": "10.48550/arXiv.2104.02735", "publisher": "arXiv", "publication_date": "2021-04-06" }, { "id": "authors:9w0n5-zah18", "collection": "authors", "collection_id": "9w0n5-zah18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200311-155918643", "type": "monograph", "title": "Enhancement of deep-subwavelength band gaps in flat spiral-based phononic metasurfaces using the trampoline phenomena", "author": [ { "family_name": "Bilal", "given_name": "Osama R.", "orcid": "0000-0003-3803-5084", "clpid": "Bilal-O-R" }, { "family_name": "Foehr", "given_name": "Andr\u00e9", "orcid": "0000-0003-0941-5424", "clpid": "Foehr-A" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "Elastic and acoustic metamaterials can sculpt dispersion of waves through resonances. In turn, resonances can give rise to negative effective properties, usually localized around the resonance frequencies, which support band gaps at subwavelength frequencies (i.e., below the Bragg-scattering limit). However, the band gaps width correlates strongly with the resonators' mass and volume, which limits their functionality in applications. Trampoline phenomena have been numerically and experimentally shown to broaden the operational frequency ranges of two-dimensional, pillar-based metamaterials through perforation. In this work, we demonstrate trampoline phenomena in lightweight and planar lattices consisting of arrays of Archimedean spirals in unit cells. Spiral-based metamaterials have been shown to support different band gap opening mechanisms, namely, Bragg-scattering, local resonances and inertia amplification. Here, we numerically analyze and experimentally realize trampoline phenomena in planar metasurfaces for different lattice tessellations. Finally, we carry out a comparative study between trampoline pillars and spirals and show that trampoline spirals outperform the pillars in lightweight, compactness and operational bandwidth.", "doi": "10.48550/arXiv.2001.10508", "publisher": "arXiv", "publication_date": "2020-01-28" }, { "id": "authors:cx124-m6686", "collection": "authors", "collection_id": "cx124-m6686", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180817-160141057", "type": "monograph", "title": "Tuning frequency band gaps of tensegrity metamaterials with local and global prestress", "author": [ { "family_name": "Amendola", "given_name": "Ada", "orcid": "0000-0002-2562-881X", "clpid": "Amendola-A" }, { "family_name": "Krushynska", "given_name": "Anastasiia", "orcid": "0000-0003-3259-2592", "clpid": "Krushynska-A" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" }, { "family_name": "Pugno", "given_name": "Nicola M.", "orcid": "0000-0003-2136-2396", "clpid": "Pugno-N-M" }, { "family_name": "Fraternali", "given_name": "Fernando", "orcid": "0000-0002-7549-6405", "clpid": "Fraternali-F" } ], "abstract": "This work studies the acoustic band structure of tensegrity metamaterials, and the possibility to tune the dispersion relation of such systems by playing with local and global prestress variables. Building on established results of the Bloch-Floquet theory, the paper first investigates the linearized response of chains composed of tensegrity units and lumped masses, which undergo small oscillations around an initial equilibrium state. The stiffness of the units in such a state varies with an internal self-stress induced by prestretching the cables forming the tensegrity units, and the global prestress induced by the application of compression forces to the terminal bases. The given results show that frequency band gaps of monoatomic and biatomic chains can be effectively altered by the fine tuning of local and global prestress parameters, while keeping material properties unchanged. Numerical results on the wave dynamics of chains under moderately large displacements confirm the presence of frequency band gaps of the examined systems in the elastically hardening regime. Novel engineering uses of the examined metamaterials are discussed.", "doi": "10.48550/arXiv.1803.03472", "publisher": "arXiv", "publication_date": "2018-03-09" }, { "id": "authors:2c626-bt454", "collection": "authors", "collection_id": "2c626-bt454", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160316-135431197", "type": "monograph", "title": "Artificial membranes biomimicking pit vipers' thermal sensing", "author": [ { "family_name": "Di Giacomo", "given_name": "Raffaele", "clpid": "Di-Giacomo-R" }, { "family_name": "Bonanomi", "given_name": "Luca", "clpid": "Bonanomi-L" }, { "family_name": "Costanza", "given_name": "Vincenzo", "orcid": "0000-0002-2409-0632", "clpid": "Costanza-V" }, { "family_name": "Maresca", "given_name": "Bruno", "clpid": "Maresca-B" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "Artificial membranes that are sensitive to temperature are needed in robotics to augment interactions with humans and the environment, and in bioengineering to improve prosthetic limbs. Existing flexible sensors achieved sensitivities of <100 mK, albeit within narrow (<5 K) temperature ranges. Other flexible devices, working in wider temperature ranges, exhibit orders of magnitude poorer responses. However, much more versatile and temperature sensitive membranes are found in animals such as pit vipers, whose pit membranes have the highest sensitivity in nature and are used to locate warm-blooded preys at distance. Here, we show that pectin films mimic the sensing mechanism of pit membranes and parallel their record performance. These films map temperature on surfaces with a sensitivity of <10 mK in a wide temperature range (40 K) and detect warm bodies at distance.", "doi": "10.48550/arXiv.1512.01161", "publication_date": "2015-12-03" }, { "id": "authors:md4gb-keb02", "collection": "authors", "collection_id": "md4gb-keb02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160316-133318246", "type": "monograph", "title": "Locally Resonant Granular Chain", "author": [ { "family_name": "Bonanomi", "given_name": "Luca", "clpid": "Bonanomi-L" }, { "family_name": "Theocharis", "given_name": "Georgios", "clpid": "Theocharis-G" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "We report the design and testing of a tunable and nonlinear mechanical metamaterial, called locally resonant granular chain. It consists of a one-dimensional array of hollow spherical particles in contact, containing local resonators. The resonant particles are made of an aluminium outer spherical shell and a steel inner mass connected by a polymeric plastic structure acting as a spring. We characterize the linear spectra of the individual particles and of one-dimensional arrays of particles using theory, numerical analysis, and experiments. A wide band gap is observed as well as tunability of the dispersive spectrum by changing the applied static load. Finally, we experimentally explore the nonlinear dynamics of the resonant particles. By using nonlinear acoustical techniques, we reveal a complex, nonclassical nonlinear dynamics.", "doi": "10.48550/arXiv.1403.1052", "publication_date": "2014-03-05" }, { "id": "authors:qq2x1-h7r58", "collection": "authors", "collection_id": "qq2x1-h7r58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160322-073625782", "type": "monograph", "title": "Tunable frequency band-gap and pulse propagation in a strongly nonlinear diatomic chain", "author": [ { "family_name": "Herbold", "given_name": "E. B.", "clpid": "Herbold-E-B" }, { "family_name": "Nesterenko", "given_name": "V. F.", "clpid": "Nesterenko-V-F" }, { "family_name": "Wang", "given_name": "S.", "clpid": "Wang-S" }, { "family_name": "Daraio", "given_name": "C.", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" } ], "abstract": "One-dimensional nonlinear phononic crystals have been assembled from periodic diatomic chains of stainless steel cylinders alternated with Polytetrafluoroethylene (PTFE)\nspheres. We report the presence of acoustic band gaps in the dispersion relation of the linearized systems and study the transformation of single and multiple pulses in linear,\nnonlinear and strongly nonlinear regimes with numerical calculations and experiments. The limiting frequencies of the band gap are within the audible frequency range (20~20,000 Hz) and can be tuned by varying the particle's material properties, mass and initial compression.\nPulses rapidly transform within very short distances from the impacted end due to the influence of the band gap in the linear and in nonlinear elastic chain. The effects of an in situ band gap created by a mean dynamic compression are observed in the strongly nonlinear wave regime.", "doi": "10.48550/arXiv.0806.4225", "publication_date": "2008-06-26" }, { "id": "authors:1a03w-6rj82", "collection": "authors", "collection_id": "1a03w-6rj82", "cite_using_url": "https://resolver.caltech.edu/CaltechSOLIDS:2007.002", "type": "monograph", "title": "Highly Nonlinear Solitary Waves in Periodic Dimer Granular Chains", "author": [ { "family_name": "Porter", "given_name": "Mason A.", "clpid": "Porter-M-A" }, { "family_name": "Daraio", "given_name": "Chiara", "orcid": "0000-0001-5296-4440", "clpid": "Daraio-C" }, { "family_name": "Herbold", "given_name": "Eric B.", "clpid": "Herbold-E-B" }, { "family_name": "Szelengowicz", "given_name": "Ivan", "clpid": "Szelengowicz-I" }, { "family_name": "Kevrekidis", "given_name": "P. G.", "orcid": "0000-0002-7714-3689", "clpid": "Kevrekidis-P-G" } ], "abstract": "We report the propagation of highly nonlinear solitary waves in heterogeneous, periodic granular media using experiments, numerical simulations, and theoretical analysis. We examine periodic arrangements of particles in experiments in which stiffer/heavier beads (stainless steel) are alternated with softer/lighter ones (polytetrafluoroethylene beads). We find excellent agreement between experiments and numerics in a model with Hertzian interactions between adjacent beads, which in turn agrees very well with a theoretical analysis of the model in the long-wavelength regime that we derive for heterogeneous environments and general bead interactions. Our analysis encompasses previously-studied examples as special cases and also provides key insights on the influence of the dimer lattice on the properties (width and propagation speed) of the obtained highly nonlinear wave\nsolutions.", "publisher": "Physical Review E", "publication_date": "2007-12-14" } ]