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1
Lamberti, Luciano. « Advances in Multi-Scale Mechanical Characterization of Materials with Optical Methods ». Materials 14, no 23 (28 novembre 2021) : 7282. http://dx.doi.org/10.3390/ma14237282.
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The mechanical characterization of materials embraces many different aspects, such as, for example, (i) to assess materials’ constitutive behavior under static and dynamic conditions; (ii) to analyze material microstructure; (iii) to assess the level of damage developed in the material; (iv) to determine surface/interfacial properties; and (v) to optimize manufacturing processes in terms of process speed and reliability and obtain the highest quality of manufactured products [...]
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Pearce, Chris, et Lukasz Kaczmarczyk. « Multi-Scale Modeling of Heterogeneous Materials and the Validation Challenge ». Applied Mechanics and Materials 70 (août 2011) : 345–50. http://dx.doi.org/10.4028/www.scientific.net/amm.70.345.
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This paper considers multi-scale modeling strategies for heterogeneous materials while also highlighting the problems of determining experimentally the micro-scale properties and validating such techniques. Multi-scale modeling techniques enable us to capture the influence of (evolving) heterogeneous material microstructures on the overall macroscopic behavior. This paper discusses computational multi-scale modeling techniques for problems both with and without poor scale separation. In developing these powerful multi-scale modeling techniques, the obvious challenge of validating both the material behavior at multiple scales and the associated scale transition methodologies, using advances in material characterization and experimental mechanics, comes into sharp focus and this will be briefly explored here.
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Hatzell, Kelsey. « (Invited) Multi-Scale Implications of Material Heterogeneity on Solid State Battery Performance ». ECS Meeting Abstracts MA2023-01, no 6 (28 août 2023) : 1073. http://dx.doi.org/10.1149/ma2023-0161073mtgabs.
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Solid state batteries are comprised of an ensemble of materials with varying structural, mechanical, chemical, and transport properties1,2. Orchestrating these materials to act synergistically and enable high power and high energy densities requires understanding how solid state electrodes and electrolytes can be engineered to enable: (1) efficient ion and electron transport and (2) maintain uniform contact between components during electrochemical cycling. Bulk processing approaching (e.g. coating, sintering, densification, etc.) do not lead to much control over material properties across various length scales (nano-to-meso). Material heterogenities exist within the cathode, solid electrolyte, and anode. In the cathode, the solid electrolyte and active material can be non-uniformly distributed leading to bottlenecks for transport and non-uniform active material utilization. In the solid electrolyte, active and passive heterogenities can influence how the ion moves between the anode and cathode and cause deleterious current focusing dynamics3,4. Finally, at the anode voiding and contact loss can occur in alkali metal anodes. This talk discusses our recent work combining operando synchrotron studies, electrochemical characterization, and advanced material characterization to unravel the implications of heterogenity on performance and degradation mechanism in solid state batteries. [1] Zaman, Wahid, and Kelsey B. Hatzell. "Processing and manufacturing of next generation lithium-based all solid-state batteries." Current Opinion in Solid State and Materials Science 26.4 (2022): 101003. [2] Ren, Yuxun, and Kelsey B. Hatzell. "Elasticity-oriented design of solid-state batteries: challenges and perspectives." Journal of Materials Chemistry A 9.24 (2021): 13804-13821. [3]Dixit, Marm B., et al. "Polymorphism of garnet solid electrolytes and its implications for grain-level chemo-mechanics." Nature Materials 21.11 (2022): 1298-1305. [4]Ren, Yuxun, Nicholas Hortance, and Kelsey B. Hatzell. "Mitigating Chemo-Mechanical Failure in Li-S Solid State Batteries with Compliant Cathodes." Journal of The Electrochemical Society 169.6 (2022): 060503.
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Li, He, Lingjie Li, Haozhang Zhong, Hanxuan Mo et Mengyuan Gu. « Hierarchical lattice : Design strategy and topology characterization ». Advances in Mechanical Engineering 15, no 6 (juin 2023) : 168781322311796. http://dx.doi.org/10.1177/16878132231179623.
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The structure-material integrated design is an art-of-state concept and be enabled by additive manufacturing. The lattice material is classified into structure as well as material because mechanical properties are determined by its topology. However, the lack of a flexible design strategy hinders the lattice achieve the structure-material integrated material candidate. This work suggests the strut-nested based strategies to effectively conduct the hierarchical lattice design. The strut in the larger-scale lattice can be replaced by the smaller-scale lattice structure through the rotation, stretching, and translation operations combining the local and global numbering, thereby complete the multi-scale lattice design. The design skills are well elucidated with custom-developed algorithm; a serious of complex lattices achieve multi-scale design. The influence of hierarchical structures in lattices on a significant parameter, strut length-to-diameter, is identified. Our work offers the alternative strategy to realize the hierarchical lattice design.
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Haussener, Sophia. « (Invited, Digital Presentation) Transport Characterization in Nano and Micron-Sized Multi-Component and Multi-Functional Materials ». ECS Meeting Abstracts MA2022-01, no 38 (7 juillet 2022) : 1649. http://dx.doi.org/10.1149/ma2022-01381649mtgabs.
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Porous and heterogeneous materials are core components in energy conversion and storage devices such as batteries, fuel cells and electrolyzers, or photoelectrochemical fuel generators. The heterogeneity and structural complexity of: i) the multi-functional nature of the applications requiring the presence of various functional materials in close vicinity, ii) nano- and micron-scale structuring of the material required to overcome the bulk material transport limitations, and iii) cheap and simple synthesis methods resulting in stochastic and complex morphologies. Understanding of the multi-physical transport phenomena and optimization of the component for enhanced performance, requires an accurate modelling and prediction of the transport properties, which heavily rely on the complex nano to micron-scale morphology. In this presentation, I will show how tomography-based direct numerical simulation scan be used for the accurate numerical characterization of the heterogeneous components’ transport properties. We will use X-ray micro-tomography for the characterization of the (thermal) transport in partially saturated gas diffusion layers/electrodes or in porous thermochemical reactors, and FIB-SEM nano-tomography for the multi-physical transport characterization of photoelectordes for water splitting and catalyst layers of CO2 reducing gas diffusion electrodes. I will show how we have built up a digital library of (photo)electrodes. Furthermore, I will show how machine learning approaches can be used to guide the design of optimized structures.
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Zhang, XiaoSheng, FuYun Zhu, GuangYi Sun et HaiXia Zhang. « Fabrication and characterization of squama-shape micro/nano multi-scale silicon material ». Science China Technological Sciences 55, no 12 (13 avril 2012) : 3395–400. http://dx.doi.org/10.1007/s11431-012-4853-2.
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Paul, Abigail, Regan Magee, Warren Wilczewski, Nathan Wichert, Caleb Gula, Rudolph Olson, Eric Shereda et al. « Characterization and Analysis of Coal-Derived Graphite for Lithium-Ion Batteries ». ECS Meeting Abstracts MA2024-01, no 4 (9 août 2024) : 670. http://dx.doi.org/10.1149/ma2024-014670mtgabs.
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Graphite is a critical material used as the negative electrode in lithium-ion batteries. Both natural and synthetic graphites are utilized, with the latter obtained from a range of carbon raw materials. In this work, efforts to synthesize graphite from coal as a domestic feedstock for synthetic graphite are reported. The performance in lithium-ion coin cells of this coal derived graphite is compared to commercial battery-grade graphite. This includes characterization of the thermodynamics of the coal derived graphite using the multi-species, multi-reaction (MSMR) model, characterization of the entropy and enthalpy of the material, and estimation of the rate capability. This enables modeling of synthetic coal-derived graphites and virtual evaluation[1] of these materials towards electric vehicle and grid storage applications. References 1. T. R. Garrick, Y. Zeng, J. B. Siegel, and V. R. Subramanian, "From Atoms to Wheels: The Role of Multi-Scale Modeling in the Future of Transportation Electrification." Journal of The Electrochemical Society 170.11 (2023): 113502.
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Nowell, Matthew M., et John O. Carpenter. « Multi-Length Scale Characterization of the Gibeon Meteorite using Electron Backscatter Diffraction ». Microscopy Today 15, no 5 (septembre 2007) : 6–11. http://dx.doi.org/10.1017/s1551929500061162.
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The Gibeon meteorite is a differentiated iron meteorite that fell in Nambia, Africa in prehistoric times, with fragments spread over an area 70 miles wide and 230 miles long. The Gibeon fall was initially discovered in 1836, and hundreds of thousands of kilograms of fragments have been recovered. These fragments represent the iron core of a meteorite that cooled and crystallized over thousands of years (Norton 2002).The microstructure of the Gibeon meteorite, which is primarily an iron-nickel alloy, consists of two phases: kamacite, a body-centered cubic material and taenite, a face-centered cubic material that metallurgists would refer to as ferrite and austenite respectively. This material initially crystallizes as taenite, and as the temperature decreases, transforms into kamacite. This meteorite is classified as a Fine Octahedrite (Of) with an average Nickel content of approximately 7.9%
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Liao, Ning Bo, Miao Zhang et Rui Jiang. « Recent Development in Multiscale Simulation of Mechanical Properties at Material Interface ». Advanced Materials Research 146-147 (octobre 2010) : 491–94. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.491.
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For nanoscale devices and structures, interface phenomena often dominate their overall thermal behavior. The feature scale of material interfaces usually originate from nanometer length and present a hierarchical nature. Considering to the limitations of the continuum mechanics on the characterization of nano-scale, the multiscale model featuring the interface could be very important in materials design. The purpose of this review is to discuss the applications of multiscale modeling and simulation techniques to study the mechanical properties at materials interface. It is concluded that a multi-scale scheme is needed for this study due to the hierarchical characteristics of interface.
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Wang, Wentao, et Linbing Wang. « Review on Design, Characterization, and Prediction of Performance for Asphalt Materials and Asphalt Pavement Using Multi-Scale Numerical Simulation ». Materials 17, no 4 (6 février 2024) : 778. http://dx.doi.org/10.3390/ma17040778.
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Asphalt pavement, which is mainly made up of the asphalt mixture, exhibits complicated mechanical behaviors under the combined effects of moving vehicle loads and external service environments. Multi-scale numerical simulation can well characterize behaviors of asphalt materials and asphalt pavement, and the essential research progress is systematically summarized from an entire view. This paper reviews extensive research works concerning aspects of the design, characterization, and prediction of performance for asphalt materials and asphalt pavement based on multi-scale numerical simulation. Firstly, full-scale performance modeling on asphalt pavement is discussed from aspects of structural dynamic response, structural and material evaluation, and wheel–pavement interaction. The correlation between asphalt material properties and pavement performance is also analyzed, and so is the hydroplaning phenomenon. Macro- and mesoscale simulations on the mechanical property characterization of the asphalt mixture and its components are then investigated, while virtual proportion design for the asphalt mixture is introduced. Features of two-dimensional and three-dimensional microscale modeling on the asphalt mixture are summarized, followed by molecular dynamics simulation on asphalt binders, aggregates, and their interface, while nanoscale behavior modeling on asphalt binders is presented. Finally, aspects that need more attention concerning this study’s topic are discussed, and several suggestions for future investigations are also presented.
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Li, L., M. Cao, Z. Li, W. Zhang, D. Shi et K. Shi. « Uniaxial tensile behavior and mechanism characterization of multi-scale fiber-reinforced cementitious materials ». Materiales de Construcción 72, no 345 (17 février 2022) : e271. http://dx.doi.org/10.3989/mc.2022.05521.
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The uniaxial tensile properties of multi-scale fiber-reinforced cementitious material (MSFRCM) with steel and polyvinyl alcohol (PVA) fibers and calcium carbonate whisker (CW) were studied. The results showed that CW improved the uniaxial tensile stiffness, strength, peak strain, and toughness of the steel-PVA hybrid fiber-reinforced cementitious material. The CW not only played a role in the small deformation stage but also improved the load holding capacity and toughness of the hybrid fiber-reinforced cementitious material during the large deformation stage. Computational models to assess the uniaxial tensile strength and toughness of the MSFRCM were established. Microstructure observations showed that the steel and PVA fibers formed a weak interfacial transition zone (ITZ) due to the “wall effect.” The CW effectively optimized the structure of the ITZ of the steel and PVA fibers through physical and chemical effects, such as filling, bridging, improving Ca(OH)2 orientation, and chemical effects. The steel fibers, PVA fibers, and CW in the MSFRCM bridged cracks at the macro, mesoscopic, and microscopic levels, respectively. As a result, we observed a fiber chain effect that improved the positive hybrid effect between the multi-scale fibers.
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Neumann, Stefan, et David Rafaja. « Correlative Multi-Scale Characterization of Nanoparticles Using Transmission Electron Microscopy ». Powders 3, no 4 (31 octobre 2024) : 531–49. http://dx.doi.org/10.3390/powders3040028.
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Chemical and physical properties of nanoparticles (NPs) are strongly influenced not only by the crystal structure of the respective material, including crystal structure defects but also by the NP size and shape. Contemporary transmission electron microscopy (TEM) can describe all these NP characteristics, however typically with a different statistical relevance. While the size and shape of NPs are frequently determined on a large ensemble of NPs and thus with good statistics, the characteristics on the atomic scale are usually quantified for a small number of individual NPs and thus with low statistical relevance. In this contribution, we present a TEM-based characterization technique, which can determine relevant characteristics of NPs in a scale-bridging way—from the crystal structure and crystal structure defects up to the NP size and morphology—with sufficient statistical relevance. This technique is based on a correlative multi-scale TEM approach that combines information on atomic scale obtained from the high-resolution imaging with the results of the low-resolution imaging assisted by a semi-automatic segmentation routine. The capability of the technique is illustrated in several examples, including Au NPs with different shapes, Au nanorods with different facet configurations, and multi-core iron oxide nanoparticles with a hierarchical structure.
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Grünewald, Tilman A., Marianne Liebi et Henrik Birkedal. « Crossing length scales : X-ray approaches to studying the structure of biological materials ». IUCrJ 11, no 5 (28 août 2024) : 708–22. http://dx.doi.org/10.1107/s2052252524007838.
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Biological materials have outstanding properties. With ease, challenging mechanical, optical or electrical properties are realised from comparatively `humble' building blocks. The key strategy to realise these properties is through extensive hierarchical structuring of the material from the millimetre to the nanometre scale in 3D. Though hierarchical structuring in biological materials has long been recognized, the 3D characterization of such structures remains a challenge. To understand the behaviour of materials, multimodal and multi-scale characterization approaches are needed. In this review, we outline current X-ray analysis approaches using the structures of bone and shells as examples. We show how recent advances have aided our understanding of hierarchical structures and their functions, and how these could be exploited for future research directions. We also discuss current roadblocks including radiation damage, data quantity and sample preparation, as well as strategies to address them.
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Samouh, Z., A. Abed, C. Cochrane, A. R. Labanieh, F. Boussu, D. Soulat, R. El-Mozznine et O. Cherkaoui. « Investigation on bio-sourced textile reinforcement for composite material based on sisal Moroccan yarns ». IOP Conference Series : Materials Science and Engineering 1266, no 1 (1 janvier 2023) : 012013. http://dx.doi.org/10.1088/1757-899x/1266/1/012013.
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Abstract The main objective of this paper aims at investigating the potential use of sisal yarn into composite material despite the inherent variability of properties of natural resources. A multi-scale approach of the behavior of sisal fiber woven reinforcements is conducted to understand and evaluate the different properties of woven reinforcements. At the yarn scale, a piezo-resistive sensor yarn was developed to assess deformations and stress concentrations in-situ in order to understand the material behavior during the weaving of woven reinforcements fibrous for bio-sourced composite materials. At the fabric scale, 2D woven reinforcements are developed based on a conventional weaving process. The production and characterization of composite sheets based on 2D woven reinforcements show the potential of sisal fiber woven reinforcements compared to natural fiber woven reinforcements from literature.
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Wang, Sijiao, Kaiming Cao, Guanwei Wang, Mengmeng Chen et Hongxi Wang. « Preparation and Properties of Epoxy Composites with Multi-Scale BN Sheets ». Applied Sciences 12, no 12 (17 juin 2022) : 6171. http://dx.doi.org/10.3390/app12126171.
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Epoxy resin is one of the most widely used thermosetting polymers and commonly applied in power electronics field. The intrinsic properties of epoxy can be improved by the introduction of inorganic filler, thus fabricating a composite material. In this paper, different scales of modified boron nitride (BN, 1 μm, 10 μm) were used to improve the thermal conductivity of epoxy resin. The surfaces BN were modification by a silane coupling agent to improve the compatibility between BN and epoxy resin. The effects of micro-and nano-BN sheets on the microstructure, breakdown strength, thermal and mechanical properties of epoxy resin composite were studied. The characterization of its morphology by scanning electron microscopy shows that nano-BN distribution is in the middle of micro-BN, forming a better bridging effect. The data of the breakdown strength and thermal conductivity indicated that when the content of micro-BN is 30 wt% and nano-BN is 20 wt%, the thermal conductivity of BN/epoxy composite was 1.52 W/m·K. In addition, the breakdown strength is 77.1 kV/mm. Thus, this type of BN-filled BN/EP composites with remarkable insulation and thermal conductivity properties would have potential for power engineering materials.
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Tronci, Giuseppe, Colin A. Grant, Neil H. Thomson, Stephen J. Russell et David J. Wood. « Multi-scale mechanical characterization of highly swollen photo-activated collagen hydrogels ». Journal of The Royal Society Interface 12, no 102 (janvier 2015) : 20141079. http://dx.doi.org/10.1098/rsif.2014.1079.
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Biological hydrogels have been increasingly sought after as wound dressings or scaffolds for regenerative medicine, owing to their inherent biofunctionality in biological environments. Especially in moist wound healing, the ideal material should absorb large amounts of wound exudate while remaining mechanically competent in situ . Despite their large hydration, however, current biological hydrogels still leave much to be desired in terms of mechanical properties in physiological conditions. To address this challenge, a multi-scale approach is presented for the synthetic design of cyto-compatible collagen hydrogels with tunable mechanical properties (from the nano- up to the macro-scale), uniquely high swelling ratios and retained (more than 70%) triple helical features. Type I collagen was covalently functionalized with three different monomers, i.e. 4-vinylbenzyl chloride, glycidyl methacrylate and methacrylic anhydride, respectively. Backbone rigidity, hydrogen-bonding capability and degree of functionalization ( F : 16 ± 12–91 ± 7 mol%) of introduced moieties governed the structure–property relationships in resulting collagen networks, so that the swelling ratio ( SR : 707 ± 51–1996 ± 182 wt%), bulk compressive modulus ( E c : 30 ± 7–168 ± 40 kPa) and atomic force microscopy elastic modulus ( E AFM : 16 ± 2–387 ± 66 kPa) were readily adjusted. Because of their remarkably high swelling and mechanical properties, these tunable collagen hydrogels may be further exploited for the design of advanced dressings for chronic wound care.
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Tirry, W., F. Coghe, S. Bouvier, M. Gasperini, L. Rabet et D. Schryvers. « A multi-scale characterization of deformation twins in Ti6Al4V sheet material deformed by simple shear ». Materials Science and Engineering : A 527, no 16-17 (juin 2010) : 4136–45. http://dx.doi.org/10.1016/j.msea.2010.03.039.
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D’Ambra, C., G. P. Lignola et A. Prota. « Multi-Scale Analysis of In-plane Behaviour of Tuff Masonry ». Open Construction and Building Technology Journal 10, no 1 (31 mai 2016) : 312–28. http://dx.doi.org/10.2174/1874836801610010312.
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Various methodologies are available today in engineering professional practice to analyse structures, in particular in the field of masonry structures. Many of the methods are derived from reinforced concrete frames but sometimes they suffer of lack of comprehensive experimental validation due to difficulties to simulate the many different kinds of masonries and they suffer from lack of critical comparison between them. In fact some methods seem to be able to provide accurate results, but are extremely expensive from a computational point of view and they require detailed material characterization and knowledge of actual geometry of the masonry and its constituents. However the usual uncertainty on the material mechanical properties and geometry details jeopardizes seriously the accuracy of the most refined analyses. Previous works by the authors remarked that nonlinear properties like as fracture energy, crucial for instance in the definition of post peak behaviour and ductility of masonry, have a crucial role at the single panel scale level analysis, while their impact is less and less crucial on the behaviour of entire walls and masonry structures. The aim of the overall work is to compare the most common methods of analysis for masonry from micro-scale to macro-scale, where not only geometrical refinement of the analysis is crucial, but also the number and details of required mechanical parameters. It is seen that macro-models are important to analyse large structures and the computational expense and required knowledge level are usually reasonable. To this scope a simple nonlinear material model for tuff masonry is proposed and results are compared between refined and simple models to simulate a tested real scale wall prototype with an opening.
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Parkin, Calvin, Tyler Mefford, Jongwoo Lim, Aram Yoon, Rui Serra-Maia, Pawan Kumar, See Wee Chee et al. « In-Situ Liquid-Electrochemical X-Ray and Electron Microscopy for Multi-Modal Energy Materials Characterization ». ECS Meeting Abstracts MA2024-01, no 46 (9 août 2024) : 2591. http://dx.doi.org/10.1149/ma2024-01462591mtgabs.
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In-situ liquid cell electron and x-ray microscopy have enabled dynamic studies of electrochemical reactions in energy materials and revealed relationships between the performance, structure, and chemical composition of these material systems. Such fundamental relationships are critical to improving the performance of batteries, catalysts, and other energy materials. Growing research interest in energy materials systems has accelerated the development of in-situ liquid-electrochemical microscopy techniques into mature and robust characterization workflows using novel and versatile scientific hardware. Multiple characterization techniques or in-situ processing steps are often required to fully understand the mechanisms governing the behavior of energy materials for all relevant length scales and environmental conditions. A multi-modal workflow combining in-situ liquid-electrochemical transmission electron, X-ray synchrotron and scanning electron microscopy methods is presented. The breadth of research applications is discussed, including the study of chemical dynamics and structural changes to micron-scale LixFePO4 battery particles during lithium-ion insertion/extraction, electrocatalytic behavior of β-Co(OH)2 platelet particles, and electrochemical oxidation of copper nanoparticles under reductive electrolytic conditions. New insights into these materials systems provided by these experiments will directly inform the development of predictive models for material performance and guide improvement of material design and synthesis. New scientific hardware and method development has been critical to in-situ nano-scale liquid cell microscopy and spectroscopy of electrochemical systems. Therefore, best-practice hardware and method design and development for these in-situ liquid-electrochemical microscopy experiments are also discussed. The connections between potentiostat, holder, and on-chip leads must be carefully considered with respect to different ground potentials, and the incorporation of real bulk-scale reference electrodes in this hardware has yielded quantitatively higher fidelity data with less degradation from further electrochemical cycling. Heating the sample or illuminating with light during in-situ electrochemical data collection has begun to further expand the range of environmental conditions that can be incorporated into experiments.
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Liu, Dong, Peter Heard, Branko Šavija, Gillian Smith, Erik Schlangen et Peter Flewitt. « Multi-scale characterization and modelling of damage evolution in nuclear Gilsocarbon graphite ». MRS Proceedings 1809 (2015) : 1–6. http://dx.doi.org/10.1557/opl.2015.433.
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ABSTRACTIn the present work, the microstructure and mechanical properties of Gilsocarbon graphite have been characterized over a range of length-scales. Optical imaging, combined with 3D X-ray computed tomography and 3D high-resolution tomography based on focus ion beam milling has been adopted for microstructural characterization. A range of small-scale mechanical testing approaches are applied including an in situ micro-cantilever technique based in a Dualbeam workstation. It was found that pores ranging in size from nanometers to tens of micrometers in diameter are present which modify the deformation and fracture characteristics of the material. This multi-scale mechanical testing approach revealed the significant change of mechanical properties, for example flexural strength, of this graphite over the length-scale from a micrometer to tens of centimeters. Such differences emphasize why input parameters to numerical models have to be undertaken at the appropriate length-scale to allow predictions of the deformation, fracture and the stochastic features of the strength of the graphite with the required confidence. Finally, the results from a multi-scale model demonstrated that these data derived from the micro-scale tests can be extrapolated, with high confidence, to large components with realistic dimensions.
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Walker, Trumann, Tara Nietzold, Niranjana Mohan Kumar, Barry Lai, Kevin Stone, Michael E. Stuckelberger et Mariana I. Bertoni. « Development of an operando characterization stage for multi-modal synchrotron x-ray experiments ». Review of Scientific Instruments 93, no 6 (1 juin 2022) : 065113. http://dx.doi.org/10.1063/5.0087050.
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It is widely accepted that micro- and nanoscale inhomogeneities govern the performance of many thin-film solar cell absorbers. These inhomogeneities yield material properties (e.g., composition, structure, and charge collection) that are challenging to correlate across length scales and measurement modalities. The challenge is compounded if a correlation is sought during device operation or in conditions that mimic aging under particular stressors (e.g., heat and electrical bias). Correlative approaches, particularly those based on synchrotron x-ray sources, are powerful since they can access several material properties in different modes (e.g., fluorescence, diffraction, and absorption) with minimal sample preparation. Small-scale laboratory x-ray instruments have begun to offer multi-modality but are typically limited by low x-ray photon flux, low spatial resolution, or specific sample sizes. To overcome these limitations, a characterization stage was developed to enable multi-scale, multi-modal operando measurements of industrially relevant photovoltaic devices. The stage offers compatibility across synchrotron x-ray facilities, enabling correlation between nanoscale x-ray fluorescence microscopy, microscale x-ray diffraction microscopy, and x-ray beam induced current microscopy, among others. The stage can accommodate device sizes up to 25 × 25 mm2, offering access to multiple regions of interest and increasing the statistical significance of correlated properties. The stage materials can sustain humid and non-oxidizing atmospheres, and temperature ranges encountered by photovoltaic devices in operational environments (e.g., from 25 to 100 °C). As a case study, we discuss the functionality of the stage by studying Se-alloyed CdTe photovoltaic devices aged in the stage between 25 and 100 °C.
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Chen, Qing Jiang, Huan Chen et Hong Wei Gao. « The Characterization of Two-Direction Vector-Valued Wavelets and its Applications in Material Engineering ». Applied Mechanics and Materials 457-458 (octobre 2013) : 36–39. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.36.
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Material science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. In this work, we study construction and properties of orthogonal two-direction vector-valued wavelet with poly-scale. Firstly, the concepts concerning two-direct-ional vector-valued waelets and wavelet wraps with multi-scale are provided. Secondly, we prop ose a construction algorim for compactly supported orthogonal two-directional vector-valued wave lets. Lastly, properties of a sort of orthogonal two-directional vector-valued wavelet wraps are char acterized by virtue of the matrix theory and the time-frequency analysis method.
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Abdi, Frank, Harsh Baid, Nima Moazami, Jay Batten, Dade Huang, Amirhossein Eftekharian, Reza Hajiha et Kamran Nikbin. « Reactive Additive Manufacturing Simulation of Thermoset Nano Graphene Inclusion ». Journal of Multiscale Modelling 11, no 03 (31 juillet 2020) : 2050004. http://dx.doi.org/10.1142/s1756973720500043.
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During the 3D printing of graphene platelet inclusion in resin, residual stresses due to thermal loading can cause wrinkle/distortion of final part. This paper presents a multi-scale modeling approach to reduce the residual thermal stress at the interphase between inclusion and resin. Material characterization is performed utilizing an integrated multi-scale modeling approach: (a) nano modeling examines effect of defects such as void shape/size/distribution, platelet orientation, etc.); (b) micro-mechanics examines constituents (platelet/matrix/interphase, residual stress); (c) macro-mechanics examines the delamination and debonding. De-homogenized multi-scale modeling approach provides detailed stiffness/strength to Finite Element Model (FEM) for full structural/thermal progressive failure analysis to address wrinkling/distortion, damage and delamination evolution via cohesive traction separation.
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Allen, Andrew J. « Selected advances in small-angle scattering and applications they serve in manufacturing, energy and climate change ». Journal of Applied Crystallography 56, no 3 (29 mai 2023) : 787–800. http://dx.doi.org/10.1107/s1600576723003898.
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Innovations in small-angle X-ray and neutron scattering (SAXS and SANS) at major X-ray and neutron facilities offer new characterization tools for researching materials phenomena relevant to advanced applications. For SAXS, the new generation of diffraction-limited storage rings, incorporating multi-bend achromat concepts, dramatically decrease electron beam emittance and significantly increase X-ray brilliance over previous third-generation sources. This results in intense X-ray incident beams that are more compact in the horizontal plane, allowing significantly improved spatial resolution, better time resolution, and a new era for coherent-beam SAXS methods such as X-ray photon correlation spectroscopy. Elsewhere, X-ray free-electron laser sources provide extremely bright, fully coherent, X-ray pulses of <100 fs and can support SAXS studies of material processes where entire SAXS data sets are collected in a single pulse train. Meanwhile, SANS at both steady-state reactor and pulsed spallation neutron sources has significantly evolved. Developments in neutron optics and multiple detector carriages now enable data collection in a few minutes for materials characterization over nanometre-to-micrometre scale ranges, opening up real-time studies of multi-scale materials phenomena. SANS at pulsed neutron sources is becoming more integrated with neutron diffraction methods for simultaneous structure characterization of complex materials. In this paper, selected developments are highlighted and some recent state-of-the-art studies discussed, relevant to hard matter applications in advanced manufacturing, energy and climate change.
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Nguyen, Wilson, Jacob F. Duncan, Paulo J. M. Monteiro et Claudia P. Ostertag. « Multi-Scale Characterization of Corrosion Initiation of Preloaded Hybrid Fiber-Reinforced Concrete Composites ». Key Engineering Materials 711 (septembre 2016) : 195–202. http://dx.doi.org/10.4028/www.scientific.net/kem.711.195.
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Many reinforced concrete structures susceptible to corrosion damage are subjected to externally applied loads, causing cracking. These cracks increase the permeability of the material, accelerating the ingress of corrosion-inducing deleterious agents. In this paper, the effect of multiple microcracking and macrocrack formation on corrosion initiation was investigated. A hybrid fiber-reinforced concrete (HyFRC), which forms ductile, distributed microcracking prior to dominant crack localization due to multiple tiers of fiber reinforcement, is being studied for its performance against corrosion damage. The effect of matrix cracking on corrosion initiation was studied with beam specimens preloaded in flexure prior to long-term corrosion exposure. Reinforced HyFRC composites were found to have a delayed corrosion initiation response due to reductions in crack widths and suppression of splitting cracks, compared to conventional reinforced concrete. The influence of microcracks on corrosion is studied using X-ray micro-computed tomography (μCT) on reinforced fiber-reinforced cementitious composites and reinforced mortar preloaded in tension.
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Wolfe, Kody D., Abigail Paul, Regan Magee, Warren Wilczewski, Nathan Wichert, Jeffrey Lowe, Jason Trembly, John A. Staser et Taylor R. Garrick. « Aging and Power Characterization of Graphite-NMC Cells Containing Coal-Derived Graphites ». ECS Meeting Abstracts MA2024-02, no 2 (22 novembre 2024) : 261. https://doi.org/10.1149/ma2024-022261mtgabs.
Texte intégralRésumé :
Virtual scale-up of battery cell and pack designs requires detailed information about the thermodynamics and kinetics of lithium storage and transport in the active materials. To investigate lithium transport and kinetics in coal-derived graphites, pouch cells containing three coal-derived anode materials and one control synthetic graphite were prepared and tested with a reference performance test (RPT) followed by hybrid pulse power characterization (HPPC) every 50th cycle. The RPT, performed at a slow rate (C/50) yields pseudo-open circuit voltage behavior that is used to study changes in active material storage mechanisms by comparing to the initial behavior through the lens of the multi-species, multi-reaction (MSMR) model.1,2 HPPC testing at various state-of-charge (SOC) measures the transient resistance and is used to extract kinetic and diffusion parameters. A comparative study between the three developed coal-derived anode materials will be presented with emphasis on enabling virtual scale-up and studying potential degradation pathways. The overarching goal of this work is to develop a workflow for validating alternative graphite materials to address graphite supply chain issues for applications in electric vehicles and grid storage. References 1. M. Verbrugge, D. Baker, B. Koch, X. Xiao, and W. Gu, J. Electrochem. Soc., 164, E3243 (2017). 2. A. Paul et al., Journal of The Electrochemical Society, 171, 039001 (2024).
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Uthaisangsuk, Vitoon, Ulrich Prahl et Wolfgang Bleck. « Microstructure Based Formability Characterization of Multi Phase Steels Using Damage Mechanics ». Key Engineering Materials 348-349 (septembre 2007) : 217–20. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.217.
Texte intégralRésumé :
Due to the coexistence of different micro structural components and their interactions, multiphase steels offer an excellent combination between high formability and strength. On the micro-scale, the fracture examination shows large influence of different phases and their distributions on the mechanical properties and failure mechanisms. Considering the influence of multiphase microstructure, an approach is presented using representative volume elements (RVE) in combination with continuum damage mechanics (CDM). Herein, the influence of the material properties of individual phases and the local states of stress on the material formability as well as the failure behavior can be examined. By means of the RVE-CDM approach, a precise criterion for the deformability characterization in sheet metal forming of multi phase steels is presented.
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Smyth, Patrick A., Itzhak Green, Robert L. Jackson et R. Reid Hanson. « Biomimetic Model of Articular Cartilage Based on In Vitro Experiments ». Journal of Biomimetics, Biomaterials and Biomedical Engineering 21 (août 2014) : 75–91. http://dx.doi.org/10.4028/www.scientific.net/jbbbe.21.75.
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Articular cartilage is a complicated material to model for a variety of reasons: its biphasic/triphasic properties, heterogeneous structure, compressibility, unique geometry, and variance between samples. However, the applications for a biomimetic, cartilage-like material are numerous and include: porous bearings, viscous dampers, robotic linkages, artificial joints, etc. This work reports experimental results on the stress-relaxation of equine articular cartilage in unconfined compression. The response is consistent with simple spring and damper systems, and gives a storage and loss moduli. This model is proposed for use in evaluating biomimetic materials, and can be incorporated into large-scale dynamic analyses to account for motion or impact. The proposed characterization is suited for high-level analysis of multi-phase materials, where separating the contribution of each phase is not desired.
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DorMohammadi, S., M. Repupilli, D. Huang, F. Abdi, Y. Song, U. Gandhi et M. Lee. « Crush simulation of automotive chopped fiber composite structures by de-homogenization multi-scale computational method ». Journal of Composite Materials 52, no 28 (13 juillet 2018) : 3935–59. http://dx.doi.org/10.1177/0021998318772012.
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A de-homogenization multi-scale computational method is proposed for the virtual performance simulation of chopped fibers composites under crush loadings. The novel approach led to the development of a multi-scale material characterization procedure for composite systems, comprising of: (1) chopped fibers homogenization based on the Eshelby and Mori–Tanaka inclusion theories, (2) orientation tensor stiffness averaging technique, (3) micro- and macro-mechanics damage and failure theories, and (4) crush resistance evaluation, as a part of the durability and damage tolerance analysis. The chopped fibers material model developed in this work is then employed in a finite element analysis, interfaced with a multi-scale progressive failure technique to track damage and fracture evolution. Comparison of the simulation results obtained for two tubes, manufactured by injection and compression molding respectively, shows good agreement with the crush test data within 10% accuracy. The proposed de-homogenization method offers a superior load resistance prediction over commercially available techniques. Furthermore, the implementation of the proposed approach in our in-house software provides traceable damage evolution and visualization of the contributing failure mechanisms, valuable sources for the design and development of new composite structures.
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Lescur, Amke, Erich Stergar, Jun Lim, Stijn Hertelé et Roumen H. Petrov. « Investigation of the Dynamic Strain Aging Effect in Austenitic Weld Metals by 3D-DIC ». Metals 13, no 2 (3 février 2023) : 311. http://dx.doi.org/10.3390/met13020311.
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Austenitic stainless steels similar to type AISI 316L are widely used structural materials in current and future nuclear reactors. Careful development and characterization of these materials and their welds is needed to verify the structural integrity of large-scale multicomponent structures. Understanding the local deformation behavior in heterogeneous materials and the mechanisms involved is key to further improve the performance and reliability of the materials at the global scale and can help in developing more accurate models and design rules. The full-field 3D digital image correlation (3D-DIC) technique was used to characterize two 316L multi-pass welds, based on cylindrical uniaxial tensile tests at room temperature, 350 °C, and 450 °C. The results were compared to solution annealed 316L material. The inhomogeneous character and dynamic behavior of the 316L base and weld materials were successfully characterized using 3D-DIC data, yielding high-quality and accurate local strain calculations for geometrically challenging conditions. The difference in character of the dynamic strain aging (DSA) effect present in base and weld materials was identified, where local inhomogeneous straining in weld material resulted in discontinuous type A Portevin–Le Châtelier (PLC) bands. This technique characterized the difference between local and global material behavior, whereas standard mechanical tests could not.
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Abdulhamid, Hakim, Paul Deconinck, Pierre-Louis Héreil et Jérôme Mespoulet. « Study of the ballistic behaviour of UHMWPE composite material : experimental characterization and numerical simulation ». EPJ Web of Conferences 183 (2018) : 01051. http://dx.doi.org/10.1051/epjconf/201818301051.
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This paper presents a comprehensive mechanical study of UHMWPE (Ultra High Molecular Weight Polyethylene) composite material under dynamic loadings. The aim of the study is to provide reliable experimental data for building and validate the composite material model under impact. Four types of characterization tests have been conducted: dynamic in-plane tension, out-of-plane compression, shear tests and plate impact tests. Then, several impacts of spherical projectiles have been performed. Regarding the numerical simulation, an intermediate scale multi-layered model (between meso and macro scale levels) is proposed. The material response is modelled with a 3d elastic orthotropic law coupled with fibre damage model. The modelling choice is governed by a balance between reliability and computing cost. Material dynamic response is unconventional [1, 2]: it shows large deformation before failure, very low shear modulus and peeling strength. Numerical simulation has been used both in the design and the analysis of tests. Many mechanical properties have been measured: elastic moduli, failure strength and EOS of the material. The numerical model is able to reproduce the main behaviours observed in the experiment. The study has highlighted the influence of temperature and fibre slipping in the impact response of the material.
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Blondé, R., E. Jimenez-Melero, L. Zhao, J. P. Wright, E. Brück, S. van der Zwaag et N. H. van Dijk. « Multi length scale characterization of austenite in TRIP steels using high-energy X-ray diffraction ». Powder Diffraction 28, no 2 (18 avril 2013) : 77–80. http://dx.doi.org/10.1017/s0885715613000237.
Texte intégralRésumé :
The martensitic transformation behavior of the meta-stable austenite phase in low alloyed TRIP steels has been studied in situ using high-energy X-ray diffraction during deformation. The stability of austenite has been studied at different length scales during tensile tests and at variable temperatures down to 153 K. A powder diffraction analysis has been performed to correlate the macroscopic behavior of the material to the observed changes in the volume fraction of the phases. Our results show that at lower temperatures the deformation induced austenite transformation is significantly enhanced and extends over a wider deformation range, resulting in a higher elongation at fracture. To monitor the austenite behavior at the level of an individual grain a high-resolution far-field detector was used. Sub-grains have been observed in austenite prior to transformation.
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Yamada, Tomoyuki, Masahiro Fukui, Kenji Terada, Masaaki Harazono, Teruya Fujisaki, Sushumna Iruvanti, Charles Carey et al. « Thermal and Reliability Demonstration of a Large Die on a Low CTE Chip Scale Package ». International Symposium on Microelectronics 2014, no 1 (1 octobre 2014) : 000068–73. http://dx.doi.org/10.4071/isom-ta31.
Texte intégralRésumé :
In organic packages, large die and large laminate body sizes are susceptible to CTE (coefficient of thermal expansion) mismatch driven warpage, stresses and strains, which can result in C4 white bumps, micro Ball Grid Array (BGA) interconnection issues, and package thermal reliability concerns. Low CTE carriers minimize these concerns and allow increased chip join yields and improved package reliability. Modeling and characterization of warpage, chip and micro BGA integrity and electrical characterization of a low CTE, Chip Scale Package (CSP) were described in an earlier paper. In this paper we report the progress on the next phase - thermal and chip package interaction (CPI) evaluation of a single chip CSP designed for use with Multi-Chip Modules (MCM). Assembly, characterization, thermal performance and reliability stress results of these low CTE CSP Single Chip Modules (SCMs) are described. Measured warpage values are compared with thermo-mechanical modeling results. Demonstration of a dual CSP design and assembly with large dies is also presented. The successful demonstration of the material set, bond and assembly processes, and reliability of a large die, high I/O CSP, followed by the demonstration of a dual CSP on a multi component carrier, are fore-runners to the development of multi-CSP MCMs.
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Shubham Bhaskar Thakare et Sai Srinivas Akhil Hawaldar. « Additive manufacturing of lightweight structures : Design and mechanical characterization ». World Journal of Advanced Engineering Technology and Sciences 14, no 2 (28 février 2025) : 317–23. https://doi.org/10.30574/wjaets.2025.14.2.0088.
Texte intégralRésumé :
Additive manufacturing has completely transformed the production of lattice structures, permitting geometries that vary widely to optimize manufacturer conditions with respect to strength-to-weight ratios in future aerospace, automotive, and biomedical industries. The present review describes developments in design, mechanical characterization, and the challenges related to lattice structures produced by AM. Major design here involves topology optimization, unit cell classification based on strut, surface, and shell designs, and bio-inspired multi-scale architectures. Mechanical performance is affected by relative density, material systems, and AM methods (as in laser powder bed fusion), with auxetic lattices demonstrating unique properties like negative Poisson's ratios. While experimental analyses as well as computational ones have revealed that bending dominated deformation occurs in the case of sinusoidal structures and energy absorption efficiency occurs in octet-truss designs. Problems pertaining to residual stress, unmelted powder, and dimensional inaccuracies were addressed through hybrid manufacturing (like investment casting) and process optimization driven by machine learning. Future work is expected to achieve lightweight, large-scale components and perhaps functionally graded materials with defect monitoring systems. This synthesis provides a template for advancing AM lattice structures towards high-performance, application-specific solutions.
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Decker, William, Alex Baker, Xin Ye, Philip Brown, Joel Stitzel et F. Scott Gayzik. « Development and Multi-Scale Validation of a Finite Element Football Helmet Model ». Annals of Biomedical Engineering 48, no 1 (13 septembre 2019) : 258–70. http://dx.doi.org/10.1007/s10439-019-02345-7.
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Abstract Head injury is a growing concern within contact sports, including American football. Computational tools such as finite element (FE) models provide an avenue for researchers to study, and potentially optimize safety tools, such as helmets. The goal of this study was to develop an accurate representative helmet model that could be used in further study of head injury to mitigate the toll of concussions in contact sports. An FE model of a Schutt Air XP Pro football helmet was developed through three major steps: geometry development, material characterization, and model validation. The fully assembled helmet model was fit onto a Hybrid III dummy head–neck model and National Operating Committee on Standards for Athletic Equipment (NOCSAE) head model and validated through a series of 67 representative impacts similar to those experienced by a football player. The kinematic and kinetic response of the model was compared to the response of the physical experiments, which included force, head linear acceleration, head angular velocity, and carriage acceleration. The outputs between the model and the physical tests were quantitatively evaluated using CORelation and Analysis (CORA), amounting to an overall averaged score of 0.76. The model described in this study has been extensively validated and can function as a building block for innovation in player safety.
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Feng, Aixin, Yupeng Cao, Heng Wang et Zhengang Zhang. « Research on Formation Mechanism of Dynamic Response and Residual Stress of Sheet Metal Induced by Laser Shock Wave ». EPJ Web of Conferences 167 (2018) : 05007. http://dx.doi.org/10.1051/epjconf/201816705007.
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In order to reveal the quantitative control of the residual stress on the surface of metal materials, the relevant theoretical and experimental studies were carried out to investigate the dynamic response of metal thin plates and the formation mechanism of residual stress induced by laser shock wave. In this paper, the latest research trends on the surface residual stress of laser shock processing technology were elaborated. The main progress of laser shock wave propagation mechanism and dynamic response, laser shock, and surface residual stress were discussed. It is pointed out that the multi-scale characterization of laser and material, surface residual stress and microstructure change is a new hotspot in laser shock strengthening technology.
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Thon, Susanna Mitrani, Arlene Chiu, Yida Lin, Hoon Jeong Lee, Sreyas Chintapalli et Botong Qiu. « (Keynote) New Materials and Spectroscopies for Colloidal Quantum Dot Solar Cells ». ECS Meeting Abstracts MA2022-02, no 20 (9 octobre 2022) : 918. http://dx.doi.org/10.1149/ma2022-0220918mtgabs.
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Colloidal quantum dots (CQDs) are an attractive third-generation material for photovoltaics due to their solution-processability, lightweight and flexible nature, and bandgap tunability, allowing them to be used as infrared materials for multi-junction solar cells. Here, we describe several methods for building new lead sulfide-based CQD materials and thin films for improving efficiencies in both single-junction and multi-junction solar cells. First, we demonstrate that the power conversion efficiency in single-junction PbS CQD solar cells is limited in part by the performance of the hole transport layer (HTL), traditionally made from ethanedithiol-passivated lead sulfide CQDs, due to the sub-optimal carrier mobility and doping density in this material. We use sulfur doping of the HTL, as well as incorporation of 2D transition metal dichalcogenide nanoflakes to address these issues and demonstrate absolute power conversion efficiency improvements of greater than 1% in single-junction devices. Next, we demonstrate a micrometer-resolution 2D characterization method with millimeter-scale field of view for assessing CQD solar cell film quality and uniformity. Our instrument simultaneously collects photoluminescence spectra, photocurrent transients, and photovoltage transients. We use this high-resolution morphology mapping to quantify the distribution and strength of the local optoelectronic property variations in CQD solar cells due to film defects, physical damage, and contaminants across nearly the entire test device area, and the extent to which these variations account for overall performance losses. We also use the massive data sets produced by this method to train machine learning models that take as input simple illuminated current-voltage measurements and output complex underlying materials parameters, greatly simplifying the characterization process for optoelectronic devices. Finally, we use artificial photonic band engineering as a method for achieving spectral selectivity in absorbing PbS CQD thin films for applications in multi-junction photovoltaics. We show that a structured periodic CQD thin film is able to maintain a photonic band structure, including the existence of a reduced photonic density of states, in the presence of weak material absorption, enabling modification of the absorption, transmission, and reflection spectra. We use a machine learning-based inverse design process to generate CQD thin film photonic structures with targeted absorption, transmission, and reflection spectra for multi-junction photovoltaics and narrow bandwidth photodetectors.
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Lim, Yong-Chae, Jiheon Jun, Yi-Feng Su, John E. Wade, Jong Keum et Feng Zhili. « Mitigating Galvanic Corrosion in Carbon Fiber Reinforced Polymer-AZ31B Dissimilar Joints through Oxide Layer-Coated Rivets ». ECS Meeting Abstracts MA2024-02, no 17 (22 novembre 2024) : 1691. https://doi.org/10.1149/ma2024-02171691mtgabs.
Texte intégralRésumé :
The major technical hurdles for lightweight multi-material vehicles lie in joining and corrosion, particularly galvanic corrosion of dissimilar material joints. In this study, the friction self-piercing rivet (F-SPR) process was utilized to spot join carbon fiber reinforced polymer (CFRP) to AZ31B Mg alloy at a coupon scale. After fabricating the dissimilar joint samples, a unique corrosion exposure test was performed to investigate galvanic corrosion of AZ31B at the joint in 0.1 M NaCl solution. A novel oxide self-formation technique was employed on alumina forming austenitic (AFA) alloy to electrically insulate the rivet/multi-material interfaces for mitigating galvanic coupling effect in the dissimilar joint. Advanced characterization and electrochemical evaluation techniques were employed to study corrosion behaviors of oxide layer formed AFA alloy. The corrosion volume assessment of AZ31B at the joint revealed that the surface oxide layer formed on AFA alloy rivets significantly reduced galvanic corrosion compared to both the untreated AFA alloy and carbon steel rivets (control).
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Lu, Yang, Stephen Thomas et Tian Jie Zhang. « Concurrent AtC Multiscale Modeling of Material Coupled Thermo-Mechanical Behaviors : A Review ». CivilEng 3, no 4 (15 novembre 2022) : 1013–38. http://dx.doi.org/10.3390/civileng3040057.
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Advances in the field of processing and characterization of material behaviors are driving innovations in materials design at a nanoscale. Thus, it is demanding to develop physics-based computational methods that can advance the understanding of material Multiphysics behaviors from a bottom-up manner at a higher level of precision. Traditional computational modeling techniques such as finite element analysis (FE) and molecular dynamics (MD) fail to fully explain experimental observations at the nanoscale because of the inherent nature of each method. Concurrently coupled atomic to the continuum (AtC) multi-scale material models have the potential to meet the needs of nano-scale engineering. With the goal of representing atomistic details without explicitly treating every atom, the AtC coupling provides a framework to ensure that full atomistic detail is retained in regions of the problem while continuum assumptions reduce the computational demand. This review is intended to provide an on-demand review of the AtC methods for simulating thermo-mechanical behavior. Emphasis is given to the fundamental concepts necessary to understand several coupling methods that have been developed. Three methods that couple mechanical behavior, three methods that couple thermal behavior, and three methods that couple thermo-mechanical behavior is reviewed to provide an evolutionary perspective of the thermo-mechanical coupling methods.
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Gupta, Saumya, Veronika Koudelková, Vladimír Hrbek et Jiří Němeček. « Micromechanical Characteristics of Hardly Deformable Mg Alloys ». Defect and Diffusion Forum 368 (juillet 2016) : 33–36. http://dx.doi.org/10.4028/www.scientific.net/ddf.368.33.
Texte intégralRésumé :
Mechanical characterization of individual microstructural phases of hardly deformable magnesium alloys is of crucial importance for the development of multi-scale material models. The magnesium alloys are used for preparation of fine tubes with diameter of a few millimeters and tens of millimeters wall thickness. It is hard to control an ordinary drawing process for the preparation of such tubes. However, the tubes can be prepared with a laser dieless drawing process that is, in contrary to conventional drawing, able to draw low formability materials and it is able to produce variable cross-sections of the tube or a wire with high precision. The magnesium alloy tubes are used in various fields as micro-electro-mechanical systems, medicine, electrical, biological and chemical fields. In this paper, preliminary microstructural studies and local mechanical characterization of pure Mg, MgCa0.8 and AZ31 magnesium alloys used for tube extrusion, is provided. The material microstructure is studied by means of scanning electron, atomic force microscopes and nanoindentation. Elastic properties and volume fractions of mechanically distinct phases that are not accessible by standard testing methods are provided in the paper.
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Cao, Maosen, Zhongqing Su, Li Cheng et Hao Xu. « A multi-scale pseudo-force model for characterization of damage in beam components with unknown material and structural parameters ». Journal of Sound and Vibration 332, no 21 (octobre 2013) : 5566–83. http://dx.doi.org/10.1016/j.jsv.2013.05.002.
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Rong, Chen, Li Shujian, Li Pengnan, Liu Xiaopeng, Qiu Xinyi, Tae Jo Ko et Jiang Yong. « Effect of fiber orientation angles on the material removal behavior of CFRP during cutting process by multi-scale characterization ». International Journal of Advanced Manufacturing Technology 106, no 11-12 (30 janvier 2020) : 5017–31. http://dx.doi.org/10.1007/s00170-020-04968-w.
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Sarmin, Atiya M., Nadia El Moussaid, Ratima Suntornnond, Eleanor J. Tyler, Yang-Hee Kim, Stefania Di Cio, William V. Megone et al. « Multi-Scale Analysis of the Composition, Structure, and Function of Decellularized Extracellular Matrix for Human Skin and Wound Healing Models ». Biomolecules 12, no 6 (16 juin 2022) : 837. http://dx.doi.org/10.3390/biom12060837.
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The extracellular matrix (ECM) is a complex mixture of structural proteins, proteoglycans, and signaling molecules that are essential for tissue integrity and homeostasis. While a number of recent studies have explored the use of decellularized ECM (dECM) as a biomaterial for tissue engineering, the complete composition, structure, and mechanics of these materials remain incompletely understood. In this study, we performed an in-depth characterization of skin-derived dECM biomaterials for human skin equivalent (HSE) models. The dECM materials were purified from porcine skin, and through mass spectrometry profiling, we quantified the presence of major ECM molecules, including types I, III, and VI collagen, fibrillin, and lumican. Rheological analysis demonstrated the sol-gel and shear-thinning properties of dECM materials, indicating their physical suitability as a tissue scaffold, while electron microscopy revealed a complex, hierarchical structure of nanofibers in dECM hydrogels. The dECM materials were compatible with advanced biofabrication techniques, including 3D printing within a gelatin microparticle support bath, printing with a sacrificial material, or blending with other ECM molecules to achieve more complex compositions and structures. As a proof of concept, we also demonstrate how dECM materials can be fabricated into a 3D skin wound healing model using 3D printing. Skin-derived dECM therefore represents a complex and versatile biomaterial with advantageous properties for the fabrication of next-generation HSEs.
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Schmid, Alexander, Christian Ellersdorfer, Eduard Ewert et Florian Feist. « Sequential Multi-Scale Modeling Using an Artificial Neural Network-Based Surrogate Material Model for Predicting the Mechanical Behavior of a Li-Ion Pouch Cell Under Abuse Conditions ». Batteries 10, no 12 (1 décembre 2024) : 425. https://doi.org/10.3390/batteries10120425.
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To analyze the safety behavior of electric vehicles, mechanical simulation models of their battery cells are essential. To ensure computational efficiency, the heterogeneous cell structure is represented by homogenized material models. The required parameters are calibrated against several characteristic cell experiments. As a result, it is hardly possible to describe the behavior of the individual battery components, which reduces the level of detail. In this work, a new data-driven material model is presented, which not only provides the homogenized behavior but also information about the components. For this purpose, a representative volume element (RVE) of the cell structure is created. To determine the constitutive material models of the individual components, different characterization tests are performed. A novel method for carrying out single-layer compression tests is presented for the characterization in the thickness direction. The parameterized RVE is subjected to a large number of load cases using first-order homogenization theory. This data basis is used to train an artificial neural network (ANN), which is then implemented in commercial FEA software LS-DYNA R9.3.1 and is thus available as a material model. This novel data-driven material model not only provides the stress–strain relationship, but also outputs information about the condition of the components, such as the thinning of the separator. The material model is validated against two characteristic cell experiments. A three-point-bending test and an indentation test of the cell is used for this purpose. Finally, the influence of the architecture of the neural network on the computational effort is discussed.
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Song, Kenan, Yiying Zhang, Navid Tajaddod et Marilyn L. Minus. « Application of the Electron Density Correlation Function for Structural Analysis of X-ray Scattering/Diffraction Information from Polymer-based Nano-Composites ». MRS Proceedings 1754 (2015) : 147–52. http://dx.doi.org/10.1557/opl.2015.760.
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ABSTRACTModern diffraction and scattering methods of X-ray radiation allow for multi-scale probing of the material morphology for both polymer-based composite films and fibers. These approaches and analyses tools can be used to map the makeup of individual grain structures in various polymer nano-composites in order to examine the effects of the fillers on nano-scale structural changes in the materials. The electron intensity correlation function, derived from Fourier transformations of the X-ray scattering pattern provides a path to analyze acquired data for space resolved domains. Here in this study, polymer-based nano-carbon composite systems are analyzed. The polymers used include polyvinyl alcohol, polyethylene, and polyacrilonitrile as matrix materials. The nano-carbon filler contribution to the grain size evolution is tracked by X-ray scattering/diffraction characterization. These results show that the relevant sizes of crystalline and amorphous domains within the lamellae structures correspond to the dispersion/distribution of the nano-filler in the composite materials. This work mainly illustrates an effective use of the correlation function to provide global morphological analysis in the composite system.
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Němeček, Jiří, Jan Maňák, Tomáš Krejčí et Jiří Němeček. « Small scale tests of cement with focused ion beam and nanoindentation ». MATEC Web of Conferences 310 (2020) : 00053. http://dx.doi.org/10.1051/matecconf/202031000053.
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Nanoindentation is used for characterization of small scale material properties of hydrated cement. It is employed as a precise loading tool on samples fabricated with Focused Ion Beam milling (FIB). The effect of heat on the microstructure of cement during different FIB energy loads is studied. Milling currents as low as 0.1 nA can be considered as save and not damaging. Micrometer sized beams were bent to reveal strength and fracture characteristics. Small scale elastic properties, tensile strength and fracture energy of individual low scale microstructural constituents of cement paste like C-S-H rich phases and Portlandite were assessed. Very high tensile strengths at the micrometer scale were observed for cement paste hydration products (200-700 MPa) with fracture energies 4-20 J/m2 The results are consistent with atomistic simulations and multi-scale modeling from available literature.
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Vigliaturo, Ruggero, Sabrina M. Elkassas, Giancarlo Della Ventura, Günther J. Redhammer, Francisco Ruiz-Zepeda, Michael J. O'Shea, Goran Dražić et Reto Gieré. « Multi-scale characterization of glaucophane from Chiavolino (Biella, Italy) : implications for international regulations on elongate mineral particles ». European Journal of Mineralogy 33, no 1 (9 février 2021) : 77–112. http://dx.doi.org/10.5194/ejm-33-77-2021.
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Abstract. In this paper, we present the results of a multi-analytical characterization of a glaucophane sample collected in the Piedmont region of northwestern Italy. Investigation methods included optical microscopy, powder X-ray diffraction, Fourier-transform infrared spectroscopy, µ-Raman spectroscopy, Mössbauer spectroscopy, electron probe microanalysis, environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy, and scanning/transmission electron microscopy combined with energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. In addition to the crystal–chemical characterization of the sample from the mesoscale to the near-atomic scale, we have also conducted an extended study on the morphology and dimensions of the mineral particles. The main finding is that studying the same particle population at different magnifications yields different results for mineral habit, dimensions, and dimensional distributions. As glaucophane may occur as an elongate mineral particle (e.g., asbestiform glaucophane occurrences in California and Nevada), the observed discrepancies therefore need to be considered when assessing potential breathability of such particles, with implications for future regulations on elongate mineral particles. While the sample preparation and particle counting methods are not directly investigated in this work, our findings suggest that different magnifications should be used when characterizing an elongate mineral particle population, irrespective of whether or not it contains asbestiform material. These results further reveal the need for developing improved regulation for elongate mineral particles. We thus propose a simple methodology to merge the datasets collected at different magnifications to provide a more complete description and a better risk evaluation of the studied particle population.
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Azpilicueta, Leyre, Peio Lopez-Iturri, Jaime Zuñiga-Mejia, Mikel Celaya-Echarri, Fidel Alejandro Rodríguez-Corbo, Cesar Vargas-Rosales, Erik Aguirre, David G. Michelson et Francisco Falcone. « Fifth-Generation (5G) mmWave Spatial Channel Characterization for Urban Environments’ System Analysis ». Sensors 20, no 18 (18 septembre 2020) : 5360. http://dx.doi.org/10.3390/s20185360.
Texte intégralRésumé :
In this work, the channel characterization in terms of large-scale propagation, small-scale propagation, statistical and interference analysis of Fifth-Generation (5G) Millimeter Wave (mmWave) bands for wireless networks for 28, 30 and 60 GHz is presented in both an outdoor urban complex scenario and an indoor scenario, in order to consider a multi-functional, large node-density 5G network operation. An in-house deterministic Three-Dimensional Ray-Launching (3D-RL) code has been used for that purpose, considering all the material properties of the obstacles within the scenario at the frequency under analysis, with the aid of purpose-specific implemented mmWave simulation modules. Different beamforming radiation patterns of the transmitter antenna have been considered, emulating a 5G system operation. Spatial interference analysis as well as time domain characteristics have been retrieved as a function of node location and configuration.
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Romano, Maria Grazia, Michele Guida, Francesco Marulo, Michela Giugliano Auricchio et Salvatore Russo. « Characterization of Adhesives Bonding in Aircraft Structures ». Materials 13, no 21 (28 octobre 2020) : 4816. http://dx.doi.org/10.3390/ma13214816.
Texte intégralRésumé :
Structural adhesives play an important role in aerospace manufacturing, since they provide fewer points of stress concentration compared to faster joints. The importance of adhesives in aerospace is increasing significantly because composites are being adopted to reduce weight and manufacturing costs. Furthermore, adhesive joints are also studied to determine the crashworthiness of airframe structure, where the main task for the adhesive is not to dissipate the impact energy, but to keep joint integrity so that the impact energy can be consumed by plastic work. Starting from an extensive campaign of experimental tests, a finite element model and a methodology are implemented to develop an accurate adhesive model in a single lap shear configuration. A single lap joint finite element model is built by MSC Apex, defining two specimens of composite material connected to each other by means of an adhesive; by the Digimat multi-scale modeling solution, the composite material is treated; and finally, by MSC’s Marc, the adhesive material is characterized as a cohesive applying the Cohesive Zone Modeling theory. The objective was to determine an appropriate methodology to predict interlaminar crack growth in composite laminates, defining the mixed mode traction separation law variability in function of the cohesive energy (Gc), the ratio between the shear strength τ and the tensile strength σ (β1), and the critical opening displacement υc.
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Lee, Hoon Jeong, Arlene Chiu, Yida Lin, Sreyas Chintapalli, Serene Kamal et Susanna Mitrani Thon. « (Invited) Parameter Prediction in Colloidal Quantum Dot Solar Cells Using Residual Neural Networks Trained on Experimental Data ». ECS Meeting Abstracts MA2024-01, no 23 (9 août 2024) : 1375. http://dx.doi.org/10.1149/ma2024-01231375mtgabs.
Texte intégralRésumé :
Colloidal quantum dots (CQDs) are an attractive third-generation material for photovoltaics, especially as infrared materials for multi-junction solar cells. Characterization and materials parameter prediction both play a critical role in the rising efficiencies in this field. However, there are numerous materials properties that need to be measured in order to fully characterize a device, leading to high research costs and slow development times. Here, we leverage recent advancements in machine learning (ML), along with a recently-demonstrated multimodal spectral characterization method [1], to predict complex materials parameters in CQD solar cells from simple current density-voltage (JV) curves, using an algorithm trained on experimental data.[2] Past work ML prediction of materials properties has focused on using simulated data due to the difficulty in collecting enough experimental data to fully train an algorithm. While it is not feasible to fabricate thousands of devices in a typical research lab, it is possible to measure several thousand points on a single device. We used a micrometer-resolution 2D characterization method with millimeter-scale field of view to acquire enough training data using only a handful of devices, while learning the spatial relationships between materials parameters. Photoluminescence, trap state density, transient photovoltage, transient photocurrent, and carrier mobility were predicted (Figure 1) by five different residual neural networks, each using a ResNet block and containing over 300k learnable parameters. The design of the networks were based on the ResNet50 architecture [3]. We also implemented a novel neighborhood approach to reduce errors and account for spatial correlations in device behavior, leading to insights into transport mechanisms and correlation lengths in CQD thin films. This method could be used to study a wide range of material systems and devices, ultimately leading to a universal prediction model that greatly simplifies the characterization process for optoelectronic devices and accelerates development times. References [1] Y. Lin, T. Gao, X. Pan, M. Kamenetska & S. M. Thon, Local Defects in Colloidal Quantum Dot Thin Films Measured via Spatially-Resolved Multi-Modal Optoelectronic Spectroscopy. Advanced Materials 32, 1906602 (2020). [2] H. J. Lee, A. Hofelmann, Y. Lin, & S. M. Thon, Predicting Materials Parameters in Colloidal Quantum Dot Photovoltaic Devices Using Machine Learning Models Trained On Experimental Data. 2022 IEEE 49th Photovoltaic Specialists Conference, 0862-0866 (2022). [3] O. Elharrouss, N. Almaadeed, S. Al-Maadeed, & Y. Akbari, Image inpainting: A review. Neural Processing Letters 51, 2007–2028 (2020). Figure 1