scholarly journals Measuring and upscaling micromechanical interactions in a cohesive granular material

Soft Matter ◽  
2021 ◽  
Author(s):  
Arnaud Hemmerle ◽  
Yuta Yamaguchi ◽  
Marcin Michal Makowski ◽  
Oliver Baeumchen ◽  
Lucas Goehring
Keyword(s):  
Mechanical Properties ◽  
Granular Material ◽  
Heterogeneous Medium ◽  
Complex Interplay ◽  
Local Interactions ◽  
Length Scales ◽  
Multiple Length Scales

The mechanical properties of a disordered heterogeneous medium depend, in general, on a complex interplay between multiple length scales. Connecting local interactions to macroscopic observables, such as stiffness or fracture,...

Simulations of Filled Polymers on Multiple Length Scales

2000 ◽  
Vol 661 ◽  
Author(s):  
Francis W. Starr ◽  
Sharon C. Glotzer
Keyword(s):  
Mechanical Properties ◽  
Filler Particle ◽  
Polymer Chains ◽  
Filled Polymers ◽  
Ginzburg Landau ◽  
Length Scales ◽  
Mesoscale Structure ◽  
Multiple Length Scales ◽  
Dynamics Simulations ◽  
Present Simulation

ABSTRACTWe present simulation results of the effect of nanoscopic and micron-sized fillers on the structure, dynamics and mechanical properties of polymer melts and blends. At the smallest length scales, we use molecular dynamics simulations to study the effect of a single nano-filler on the structure and dynamics of the surrounding melt. We find a tendency for polymer chains to be elongated and flattened near the filler surface. Additionally, the simulations show that the dynamics of the polymers can be dramatically altered by the choice of polymer-filler interactions. We use time-dependent Ginzburg-Landau simulations to model the mesoscale phase-separation of an ultra-thin blend film in the presence of an immobilized filler particle. These simulations show the influence of filler particles on the mesoscale blend structure when one component of the blend preferentially wets the filler. Finally, we present some preliminary finite element calculations used to predict the effect of mesoscale structure on macroscopic ultrathin film mechanical properties.

Stress fields in granular material and implications for performance of robot locomotion over granular media

2015 ◽  
Vol 8 (1) ◽  
pp. 2005-2009
Author(s):  
Diandong Ren ◽  
Lance M. Leslie ◽  
Congbin Fu
Keyword(s):  
Mechanical Properties ◽  
Granular Material ◽  
Granular Media ◽  
Rotation Frequency ◽  
Legged Locomotion ◽  
Working Environment ◽  
Navier Stokes ◽  
Maximum Speed ◽  
Sigmoid Curve ◽  
Multi Body

 Legged locomotion of robots has advantages in reducing payload in contexts such as travel over deserts or in planet surfaces. A recent study (Li et al. 2013) partially addresses this issue by examining legged locomotion over granular media (GM). However, they miss one extremely significant fact. When the robot’s wheels (legs) run over GM, the granules are set into motion. Hence, unlike the study of Li et al. (2013), the viscosity of the GM must be included to simulate the kinematic energy loss in striking and passing through the GM. Here the locomotion in their experiments is re-examined using an advanced Navier-Stokes framework with a parameterized granular viscosity. It is found that the performance efficiency of a robot, measured by the maximum speed attainable, follows a six-parameter sigmoid curve when plotted against rotating frequency. A correct scaling for the turning point of the sigmoid curve involves the footprint size, rotation frequency and weight of the robot. Our proposed granular response to a load, or the ‘influencing domain’ concept points out that there is no hydrostatic balance within granular material. The balance is a synergic action of multi-body solids. A solid (of whatever density) may stay in equilibrium at an arbitrary depth inside the GM. It is shown that there exists only a minimum set-in depth and there is no maximum or optimal depth. The set-in depth of a moving robot is a combination of its weight, footprint, thrusting/stroking frequency, surface property of the legs against GM with which it has direct contact, and internal mechanical properties of the GM. If the vehicle’s working environment is known, the wheel-granular interaction and the granular mechanical properties can be grouped together. The unitless combination of the other three can form invariants to scale the performance of various designs of wheels/legs. Wider wheel/leg widths increase the maximum achievable speed if all other parameters are unchanged.

Fracture resistance of human cortical bone across multiple length-scales at physiological strain rates

Biomaterials ◽  
2014 ◽  
Vol 35 (21) ◽  
pp. 5472-5481 ◽  
Author(s):  
Elizabeth A. Zimmermann ◽  
Bernd Gludovatz ◽  
Eric Schaible ◽  
Björn Busse ◽  
Robert O. Ritchie
Keyword(s):  
Cortical Bone ◽  
Fracture Resistance ◽  
Strain Rates ◽  
Physiological Strain ◽  
Length Scales ◽  
Human Cortical Bone ◽  
Multiple Length Scales

Patterning of Soft Matter across Multiple Length Scales

2016 ◽  
Vol 26 (16) ◽  
pp. 2609-2616 ◽  
Author(s):  
Pim van der Asdonk ◽  
Hans C. Hendrikse ◽  
Marcos Fernandez-Castano Romera ◽  
Dion Voerman ◽  
Britta E. I. Ramakers ◽  
...  
Keyword(s):  
Soft Matter ◽  
Length Scales ◽  
Multiple Length Scales

Surface integrity analysis of machined Inconel 718 over multiple length scales

CIRP Annals ◽  
2012 ◽  
Vol 61 (1) ◽  
pp. 99-102 ◽  
Author(s):  
Rachid M'Saoubi ◽  
Tommy Larsson ◽  
José Outeiro ◽  
Yang Guo ◽  
Sergey Suslov ◽  
...  
Keyword(s):  
Surface Integrity ◽  
Inconel 718 ◽  
Length Scales ◽  
Multiple Length Scales ◽  
Integrity Analysis

An Energetic Approach to Modeling Cytoskeletal Architecture in Maturing Cardiomyocytes

2021 ◽  
Author(s):  
William F Sherman ◽  
Mira Asad ◽  
Anna Grosberg
Keyword(s):  
Cardiac Tissue ◽  
Length Scales ◽  
Functional Changes ◽  
Physical Constraints ◽  
Scale Parameters ◽  
Structure And Dynamics ◽  
Energetic Approach ◽  
Cytoskeletal Network ◽  
Multiple Length Scales ◽  
Potential Factors

Abstract Through a variety of mechanisms, a healthy heart is able to regulate its structure and dynamics across multiple length scales. Disruption of these mechanisms can have a cascad- ing effect, resulting in severe structural and/or functional changes that permeate across different length scales. Due to this hierarchical structure, there is interest in understand- ing how the components at the various scales coordinate and influence each other. However, much is unknown regarding how myofibril bundles are organized within a densely packed cell and the influence of the subcellular components on the architecture that is formed. To elucidate potential factors influencing cytoskeletal development, we proposed a compu- tational model that integrated interactions at both the cel- lular and subcelluar scale to predict the location of indi- vidual myofibril bundles that contributed to the formation of an energetically favorable cytoskeletal network. Our model was tested and validated using experimental metrics derived from analyzing single cell cardiomyocytes. We demonstrated that our model-generated networks were capable of repro- ducing the variation observed in experimental cells at different length scales as a result of the stochasticity inher- ent in the different interaction between the various cellu- lar components. Additionally, we showed that incorporat- ing length-scale parameters resulted in physical constraints that directed cytoskeletal architecture towards a structurally consistent motif. Understanding the mechanisms guiding the formation and organization of the cytoskeleton in individual cardiomyocytes can aid tissue engineers towards developing functional cardiac tissue.

Osteogenesis Imperfecta: Molecular and Mesoscale Disease Mechanisms

2009 ◽  
Author(s):  
Alfonso Gautieri ◽  
Sebastien Uzel ◽  
Simone Vesentini ◽  
Alberto Redaelli ◽  
Markus J. Buehler
Keyword(s):  
Mechanical Properties ◽  
Osteogenesis Imperfecta ◽  
Multiple Scales ◽  
Genetic Disorder ◽  
Single Point ◽  
Single Point Mutation ◽  
Mesoscale Simulation ◽  
Disease Mechanisms ◽  
Multiple Length Scales ◽  
Collagenous Tissues

Osteogenesis Imperfecta (OI) is a genetic disorder in collagen characterized by mechanically weakened tendon and fragile bones that affects more than 1 in 10,000 individuals. Even though many studies have attempted to associate specific mutation types with phenotypic severity, the mechanisms by which a single point mutation influences the mechanical behavior of tissues at multiple length-scales remain unknown. Here we show by a hierarchy of full atomistic and mesoscale simulation that OI mutations severely compromise the mechanical properties of collagenous tissues at multiple scales, from single molecules to collagen fibrils.

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