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MULTISCALE mechanics OF BIOLOGICAL AND BIOLOGICALLY INSPIRED MATERIALS AND STRUCTURES

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Acta Mechanica Solida Sinica 2010年第6期23卷 471-483页

作者： Markus J.Buehler laboratory for atomistic and molecular mechanics Department of Civil and Environmental EngineeringMassachusetts Institute of Technology Center for Computational Engineering Massachusetts Institute of Technology Center for Materials Science and Engineering Massachusetts Institute of Technology

The world of natural materials and structures provides an abundance of applications in which mechanics is a critical issue for our understanding of functional material properties. In particular, the mechanical properties of biological materials and structures play an important role in virtually all physiological processes and at all scales, from the molecular and nanoscale to the macroscale, linking research fields as diverse as genetics to structural mechanics in an approach referred to as materiomics. Example cases that illustrate the importance of mechanics in biology include mechanical support provided by materials like bone, the facilitation of locomotion capabilities by muscle and tendon, or the protection against environmental impact by materials as the skin or armors. In this article we review recent progress and case studies, relevant for a variety of applications that range from medicine to civil engineering. We demonstrate the importance of fundamental mechanistic insight at multiple time- and length-scales to arrive at a systematic understanding of materials and structures in biology, in the context of both physiological and disease states and for the development of de novo biomaterials. Three particularly intriguing issues that will be discussed here include： First, the capacity of biological systems to turn weakness to strength through the utilization of multiple structural levels within the universality-diversity paradigm. Second, material breakdown in extreme and disease conditions. And third, we review an example where the hierarchical design paradigm found in natural protein materials has been applied in the development of a novel hiomaterial based on amyloid protein.

关键词： biological materials materiomics mechanics mechanical properties mutability,tunability deformation failure

Designing architected materials for mechanical compression via simulation, deep learning, and experimentation

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npj Computational Materials 2023年第1期9卷 1534-1542页

作者： Andrew J.Lew Kai Jin Markus J.Buehler laboratory for atomistic and molecular mechanics(lamm) Massachusetts Institute of Technology77 Massachusetts Ave.CambridgeMA 02139USA Department of Chemistry Massachusetts Institute of Technology77 Massachusetts Ave.CambridgeMA 02139USA Center for Computational Science and Engineering Schwarzman College of ComputingMassachusetts Institute of Technology77 Massachusetts Ave.CambridgeMA 02139USA

Architected materials can achieve enhanced properties compared to their plain *** architecting serves as a powerful design lever to achieve targeted behavior without changing the base ***,the connection between architected structure and resultant properties remains an open field of great interest to many fields,from aerospace to civil to automotive ***,we focus on properties related to mechanical compression,and design hierarchical honeycomb structures to meet specific values of stiffness and compressive *** do so,we employ a combination of techniques in a singular workflow,starting with molecular dynamics simulation of the forward design problem,augmenting with data-driven artificial intelligence models to address the inverse design problem,and verifying the behavior of de novo structures with experimentation of additively manufactured *** thereby demonstrate an approach for architected design that is generalizable to multiple material properties and agnostic to the identity of the base material.

关键词： thereby additive starting

Elasticity,Strength and Resilience:A Comparative Study on Mechanical Signatures ofα-Helix,β-Sheet and Tropocollagen Domains

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Nano Research 2008年第1期1卷 63-71页

作者： Markus J.Buehler Sinan Keten laboratory for atomistic and molecular mechanics Department of Civil and Environmental EngineeringMassachusetts Institute of Technology77 Massachusetts Ave.Room 1-235 A&BCambridgeMA02139-4307USA

In biology,structural design and materials engineering is unified through formation of hierarchical features with atomic resolution,from nano to *** molecular building blocks are particularly prevalent in all structural protein materials:alpha helices(AHs),beta-sheets(BSs)and tropocollagen(TC).In this article we present a comparative study of these three key building blocks by focusing on their mechanical signatures,based on results from full-atomistic simulation *** fi nd that each of the basic structures is associated with a characteristic material behavior:AH protein domains provide resilience at large deformation through energy dissipation at low force levels,BS protein domains provide great strength under shear loading,and tropocollagen molecules provide large elasticity for deformation *** suggests that AHs,BSs,and TC molecules have mutually exclusive mechanical *** correlate each of these basic properties with the molecule’s structure and the associated fundamental rupture *** study may enable the use of abundant protein building blocks in nanoengineered materials,and may provide critical insight into basic biological mechanisms for bio-inspired *** transfer towards the design of novel nanostructures could lead to new multifunctional and mechanically active,tunable,and changeable materials.

关键词： Fracture biology hierarchical materials materiomics proteins self-assembly mechanical properties theory strength

Linking atomic structural defects to mesoscale properties in crystalline solids using graph neural networks

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npj Computational Materials 2022年第1期8卷 1886-1898页

作者： Zhenze Yang Markus J.Buehler laboratory for atomistic and molecular mechanics(lamm) Massachusetts Institute of Technology77 Massachusetts Ave.CambridgeMA02139USA Department of Materials Science and Engineering Massachusetts Institute of Technology77 Massachusetts Ave.CambridgeMA02139USA Center for Computational Science and Engineering Schwarzman College of ComputingMassachusetts Institute of Technology77 Massachusetts AveCambridgeMA02139USA Center for Materials Science and Engineering 77 Massachusetts Ave CambridgeMA02139USA

Structural defects are abundant in solids,and vital to the macroscopic materials ***,a defect-property linkage typically requires significant efforts from experiments or simulations,and often contains limited information due to the breadth of nanoscopic design *** we report a graph neural network(GNN)-based approach to achieve direct translation between mesoscale crystalline structures and atom-level properties,emphasizing the effects of structural *** end-to-end method offers great performance and generality in predicting both atomic stress and potential energy of multiple systems with different ***,the approach also precisely captures derivative properties which strictly observe physical laws and reproduces evolution of properties with varying boundary *** incorporating a genetic algorithm,we then design de novo atomic structures with optimum global properties and target local *** method would significantly enhance the efficiency of evaluating atomic behaviors given structural imperfections and accelerates the design process at the meso-level.

关键词： structural solids crystalline

Computational and theoretical modeling of intermediate filament networks:Structure,mechanics and disease

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Acta Mechanica Sinica 2012年第4期28卷 941-950页

作者： Zhao Qin Markus J. Buehler laboratory for atomistic and molecular mechanics (lamm) Department of Civil and Environmental Engineering 77 Massachusetts Ave. Massachusetts Institute of Technology Room 1-235 A&B Cambridge 02139 MA USA Center for Computational Engineering Massachusetts Institute of Technology 77 Massachusetts Ave. Cambridge MA 02139 USA Center for Materials Science and Engineering Massachusetts Institute of Technology77 Massachusetts Ave. Cambridge MA 02139 USA

Intermediate filaments, in addition to microtubules and actin microfilaments, are one of the three major components of the cytoskeleton in eukaryotic cells. It was discovered during the recent decades that in most cells, intermediate filament proteins play key roles to reinforce cells subjected to large-deformation, and that they participate in signal transduction, and it was proposed that their nanome- chanical properties are critical to perform those functions. However, it is still poorly understood how the nanoscopic structure, as well as the combination of chemical composition, molecular structure and interfacial properties of these protein molecules contribute to the biomechanical properties of filaments and filament networks. Here we review recent progress in computational and theoretical studies of the intermediate filaments network at various levels in the protein＇s structure. A multiple scale method is discussed, used to couple molecular modeling with atomistic detail to larger-scale material properties of the networked material. It is shown that a finer-trains-coarser method- ology as discussed here provides a useful tool in understanding the biomechanical property and disease mechanism of intermediate filaments, coupling experiment and simulation. It further allows us to improve the understanding of associated disease mechanisms and lays the foundation for engineering the mechanical properties of biomaterials.

关键词： Intermediate filament network - Multiple scale method Nanoscopic structure mechanics Disease mechanism molecular mechanics

atomistic simulation study of tensile deformation in bulk nanocrystalline bcc iron

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Science China(Physics,mechanics & Astronomy) 2012年第9期55卷 1657-1663页

作者： YUAN FuPing State Key laboratory of Nonlinear mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

In the present work,the mechanical properties of bulk nanocrystalline(NC) bcc Fe under tensile deformation have been studied by molecular dynamics(MD) *** flow stress was found to decrease with grain refinement below 13.54 nm,indicating a breakdown in the Hall-Petch relation.A change from grain boundary(GB) mediated dislocation activities to GB activities may be a possible explanation of the breakdown in the Hall-Petch *** results also indicate that the average flow stress increases with increasing strain rates and decreasing *** induced phase transformations were observed during the tensile deformation of NC Fe,and such phase transformations were found to be reversible with respect to the applied *** maximum fraction of the cp atoms was also found to increase with increasing applied *** phase transformation occurred in the stacking fault zone due to dislocation activities for large grain size(13.54 nm),while significant phase transformation occurred in the GBs due to GB activities for small grain size(3.39 nm).At deformation temperature of 900 K and above,no apparent phase transformation occurred because all atoms at GBs and grain interior could easily rearrange their position by thermal activation to form local vacancies/disordered structures rather than ordered close packed(cp) structures.

关键词： molecular dynamics simulation phase transformation dislocation activities grain boundary diffusion iron

Mechanical properties of crosslinks controls failure mechanism of hierarchical intermediate filament networks

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Theoretical & Applied mechanics Letters 2012年第1期2卷 27-31页

作者： Zhao Qin Markus J. Buehler laboratory for atomistic and molecular mechanics （lamm） Department of Civil and Environmental Engineering Massachusetts Institute of Technology 77 Massachusetts Ave. Room 1-235 A＆B Cambridge MA 02139 USA Center for Computational Engineering Massachusetts Institute of Technology 77 Massachusetts Ave. Cambridge MA 02139 USA Center for Materials Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Ave. Cambridge MA 02139 USA

Intermediate filaments are one of the key components of the cytoskeleton in eukaryotic cells, and their mechanical properties are found to be equally important for physiological function and disease. While the mechanical properties of single full length filaments have been studied, how the mechanical properties of crosslinks affect the mechanical property of the intermediate filament network is not well understood. This paper applies a mesoscopic model of the intermediate network with varied crosslink strengths to investigate its failure mechanism under the extreme mechanical loading. It finds that relatively weaker crosslinks lead to a more flaw tolerant intermediate filament network that is also 23% stronger than the one with strong crosslinks. These findings suggest that the mechanical properties of interfacial components are critical for bioinspired designs which provide intriguing mechanical properties.

关键词： failure mechanism flow tolerance intermediate filament protein network soft material,rupture crosslink strength bioinspired design

The effect of electric charge on the mechanical properties of graphene

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Science China(Physics,mechanics & Astronomy) 2013年第6期56卷 1148-1156页

作者： HAO Peng GAO YuanWen ZHOU YouHe Key laboratory of mechanics on Disaster and Environment in Western China The Ministry of Education of Chinaand Department of Mechanics and Engineering SciencesCollege of Civil Engineering and MechanicsLanzhou University

The effect of electric charge on the mechanical properties of graphene under tensile loading is investigated by using molecular dynamics method.A modified atomistic moment method based on the classical electrostatics theory is proposed to obtain the distribution of extra charges induced by an external electric field and net electric charges stored in *** electrostatic interactions between charged atoms are calculated using the coulomb *** results show that the Young's modulus and the critical fracture stress under uniaxial tension decrease with the increase of electric potential and net charges on *** failure of graphene induced by electric charges is found to be controlled by charge *** results indicate that the carbon-carbon bonds at the edge of graphene will break first.

关键词： charge distribution fracture mechanism electric charge mechanics

atomistic simulations of martensitic transformation processes for metastable FeMnCoCr high-entropy alloy

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Science China(Technological Sciences) 2023年第4期66卷 998-1006页

作者： WANG Peng LIN YiCheng CAO Yu ZHAO HaoRan LI QianQian WANG HongTao Shanghai Key laboratory of mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Center for X-mechanics Zhejiang UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityHangzhou 310027China Institute of Applied mechanics Zhejiang UniversityHangzhou 310027China

Non-equiatomic FeMnCoCr high-entropy alloy(HEA),which exhibits a great potential to break the strength-ductility trade-off relationship,has drawn abundant attention from researchers in ***,atomic simulations of such excellent alloys are limited due to the lack of proper interatomic *** this work,the complete martensitic transformation of nonequiatomic HEA is reproduced via atomic simulations with a novel interatomic potential under EAM *** physical parameters of interatomic potential agree well with experimental measurements and first-principles *** to the atomic simulation results of poly-crystalline under tension and compression,two basic transition models of TRIP-DP-HEA for martensitic transformation are revealed,i.e.,the overlapping of intrinsic stacking faults or the growth of hcp laminates ***,the pathway for martensitic transformation is elucidated with the gliding of Shockley partial dislocations of 1/6burgers vectors.

关键词： dual-phase high entropy-alloy molecular dynamics simulation FeMn-steels martensitic transformation