scholarly journals Totimorphic assemblies from neutrally stable units

2021 ◽  
Vol 118 (42) ◽  
pp. e2107003118
Author(s):  
Gaurav Chaudhary ◽  
S. Ganga Prasath ◽  
Edward Soucy ◽  
L. Mahadevan
Keyword(s):  
Mechanical Response ◽  
Multiple Scales ◽  
Plastic Material ◽  
Structural Materials ◽  
Unit Cell ◽  
Rigid Plastic ◽  
Deformation Response ◽  
Material Theory ◽  
Hinged Structure ◽  
Kinematic Mechanisms

Inspired by the quest for shape-shifting structures in a range of applications, we show how to create morphable structural materials using a neutrally stable unit cell as a building block. This unit cell is a self-stressed hinged structure with a one-parameter family of morphing motions that are all energetically equivalent. However, unlike kinematic mechanisms, the unit cell is not infinitely floppy and instead exhibits a tunable mechanical response akin to that of an ideal rigid-plastic material. Theory and simulations allow us to explore the properties of planar and spatial assemblies of neutrally stable elements, and solve the inverse problem of designing assemblies that can morph from one given shape into another. Simple experimental prototypes of these assemblies corroborate our theoretical results and show that the addition of switchable hinges allows us to create load-bearing structures. Altogether, totimorphs pave the way for structural materials whose geometry and deformation response can be controlled independently and at multiple scales.

Machine Learning for Structural Materials

2020 ◽  
Vol 50 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Taylor D. Sparks ◽  
Steven K. Kauwe ◽  
Marcus E. Parry ◽  
Aria Mansouri Tehrani ◽  
Jakoah Brgoch
Keyword(s):  
Machine Learning ◽  
Data Science ◽  
Mechanical Response ◽  
Materials Science ◽  
Multiple Scales ◽  
Dimensional Space ◽  
Structural Materials ◽  
High Entropy ◽  
Composition Property ◽  
Using Data

The development of structural materials with outstanding mechanical response has long been sought for innumerable industrial, technological, and even biomedical applications. However, these compounds tend to derive their fascinating properties from a myriad of interactions spanning multiple scales, from localized chemical bonding to macroscopic interactions between grains. This diversity has limited the ability of researchers to develop new materials on a reasonable timeline. Fortunately, the advent of machine learning in materials science has provided a new approach to analyze high-dimensional space and identify correlations among the structure-composition-property-processing relationships that may have been previously missed. In this review, we examine some successful examples of using data science to improve known structural materials by analyzing fatigue and failure, and we discuss approaches to develop entirely new classes of structural materials in complex composition spaces including high-entropy alloys and bulk metallic glasses. Highlighting the recent advancement in this field demonstrates the power of data-driven methodologies that will hopefully lead to the production of market-ready structural materials.

The Role of Mechanical Tension in Neurons

2010 ◽  
Vol 1274 ◽  
Author(s):  
Taher Saif ◽  
Jagannathan Rajagopalan ◽  
Alireza Tofangchi
Keyword(s):  
Mechanical Response ◽  
Mechanical Forces ◽  
Active Tension ◽  
Mechanical Tension ◽  
Deformation Response ◽  
Linear Force ◽  
Tension Regulation ◽  
Over Time

AbstractWe used high resolution micromechanical force sensors to study the in vivo mechanical response of embryonic Drosophila neurons. Our experiments show that Drosophila axons have a rest tension of a few nN and respond to mechanical forces in a manner characteristic of viscoelastic solids. In response to fast externally applied stretch they show a linear force-deformation response and when the applied stretch is held constant the force in the axons relaxes to a steady state value over time. More importantly, when the tension in the axons is suddenly reduced by releasing the external force the neurons actively restore the tension, sometimes close to their resting value. Along with the recent findings of Siechen et al (Proc. Natl. Acad. Sci. USA 106, 12611 (2009)) showing a link between mechanical tension and synaptic plasticity, our observation of active tension regulation in neurons suggest an important role for mechanical forces in the functioning of neurons in vivo.

Stamping Rectangular Plates into Doubly-Curved Dies

1984 ◽  
Vol 198 (2) ◽  
pp. 109-125 ◽  
Author(s):  
T X Yu ◽  
W Johnson ◽  
W J Stronge
Keyword(s):  
Plastic Material ◽  
Rectangular Plates ◽  
Rigid Plastic ◽  
Punch Force ◽  
Plate Buckling ◽  
Rigid Plastic Material ◽  
Force Contact ◽  
Curvature Distribution ◽  
Doubly Curved ◽  
Deformation Modes

Shallow spheroidal shell segments have been press formed from rectangular plates by stamping between a die and matching punch that have two degrees of curvature. Experiments on mild steel, copper and aluminium plates that were not clamped in the die have measured the punch force, contact regions and final curvature distribution; and have observed plate buckling for a range of die curvature ratios and plate sizes. An analysis based on a rigid/plastic material idealization and decoupled in-plane forces and bending moments has been correlated with these experiments. The sequence of deformation modes has been identified; initially these are bending but in later stages, in-plane forces predominate.

A Micro-Architectural Based Structural Model for Elastomeric Electrospun Scaffolds

2010 ◽  
Author(s):  
Antonio D’Amore ◽  
John A. Stella ◽  
David E. Schmidt ◽  
William R. Wagner ◽  
Michael S. Sacks
Keyword(s):  
Tissue Engineering ◽  
Structural Model ◽  
Mechanical Response ◽  
Multiple Scales ◽  
Sem Images ◽  
Form Complex ◽  
Novel Approach ◽  
Structural Deformations ◽  
Mechanical Models ◽  
Specific Tissue

Interest in electrospun polymeric nano-microfibers for tissue engineering applications has rapidly grown during the last decade. In spite of this technique’s flexibility and ability to form complex fiber assemblies, additional studies are required to elucidate how the fibrous microstructure translates into specific tissue (or meso-scale) level mechanical behavior. Deterministic structural models can quantify how key structures contribute to the mechanical response as a function of bulk deformation across multiple scales, as well as provide a better understanding of cellular mechanical response to local micro-structural deformations. Our ultimate aim is to utilize such models to assist tissue engineering scaffold design. In the current work, we present a novel approach to automatically quantify key micro-architectural descriptors (fiber overlaps, connectivity, orientation, and diameter) from SEM images of electrospun poly (ester urethane) urea (PEUU) to recreate statistically equivalent scaffold mechanical models. An appropriate representative volume element (RVE) size was determined by quantifying the point of stabilization of the architectural descriptors over image areas of increasing size. Material models were then generated specifying: fiber overlap density, fiber orientation, connectivity and fiber diameter. Macro-meso mechanical response was predicted via FEM simulations.

Places and Causes of Mismanaged Plastic Materials in the Life Cycle of Flexible Plastic Packaging Based on Mechanical Recycling Context

2021 ◽  
Vol 888 ◽  
pp. 129-138
Author(s):  
Munzir Hadengganan ◽  
Djoko Sihono Gabriel
Keyword(s):  
Life Cycle ◽  
Plastic Material ◽  
Life Cycles ◽  
Plastic Waste ◽  
Production Cycle ◽  
Mechanical Recycling ◽  
Rigid Plastic ◽  
Plastic Packaging ◽  
Quality Degradation ◽  
Plastic Materials

Plastic waste has become a big issue in the world for its large amount of plastic waste in the sea. Most of the plastic waste is plastic packaging which consists of flexible and rigid plastic packaging. This research discusses flexible plastic packaging. Until now, most researches on the loss of plastic materials discuss how to manage plastic waste disposal once it has been used by community: only a few discuss production cycle: while none of them discusses flexible plastic packaging area. This research aims to examine the number of mismanaged materials throughout flexible plastic packaging life cycle using a combination of Material Flow Analysis (MFA) and Life Cycle Analysis (LCA). Based on the literature review, interviews and observations conducted by the author to all stakeholders in the life cycle of flexible plastic packaging, mismanagement of plastic material occurred in each cycle, mostly caused by quality degradation of flexible plastic that could cause plastic waste was not acceptable in the mechanical recycle. The results of this study show that: (1) mismanaged material occurred in all cycles throughout the life cycles of flexible plastic packaging, (2) quality degradation is the main caused of mismanaged material in several cycles, and (3) the mismanaged materials in the life cycle of flexible plastic packaging were 98.29%.

scholarly journals INFLUENCE OF PRINTING AND LOADING DIRECTION ON MECHANICAL RESPONSE IN 3D PRINTED MODELS OF HUMAN TRABECULAR BONE

2018 ◽  
Vol 18 ◽  
pp. 24 ◽  
Author(s):  
Tomáš Doktor ◽  
Ivana Kumpová ◽  
Sebastian Wroński ◽  
Maciej Śniechowski ◽  
Jacek Tarasiuk ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Mechanical Response ◽  
Plastic Region ◽  
Human Donor ◽  
Deformation Response ◽  
Human Trabecular Bone ◽  
Loading Mode ◽  
Loading Direction ◽  
3D Printed ◽  
X Ray Computed

The paper deals with investigation on directional variations of mechanical response in 3D printed models of human trabecular bone. Sample of trabecular bone tissue was resected from human donor and 3D model was obtained by X-ray computed tomography. Then a series of cubical samples was prepared by additive manufacturing technique and tested by uniaxial compression loading mode. Mechanical response was compared in nine different combinations of direction of 3D printing and loading direction. The results show neglectible influence on the deformation response in elastic region (stiffness) and significant changes of the behaviour in plastic region (stress and strain at yield point, strain at full collapse).

Theory of compression of a compressible rigid-plastic material

1974 ◽  
Vol 10 (3) ◽  
pp. 323-326
Author(s):  
I. S. Degtyarev ◽  
V. L. Kolgomorov
Keyword(s):  
Plastic Material ◽  
Rigid Plastic ◽  
Rigid Plastic Material

Structure, Process, and Material Influences for 3D Printed Lattices Designed With Mixed Unit Cells

2020 ◽  
Author(s):  
Gabriel Briguiet ◽  
Paul F. Egan
Keyword(s):  
Elastic Modulus ◽  
Mechanical Testing ◽  
Mechanical Response ◽  
Cell Types ◽  
Unit Cell ◽  
Ultraviolet Curing ◽  
Mechanical Responses ◽  
Lattice Design ◽  
Unit Cells ◽  
3D Printed

Abstract Emerging 3D printing technologies are enabling the design and fabrication of novel architected structures with advantageous mechanical responses. Designing complex structures, such as lattices, with a targeted response is challenging because build materials, fabrication process, and topological design have unique influences on the structure’s mechanical response. Changing any factor may have unanticipated consequences, even for simpler lattice structures. Here, we conduct mechanical compression experiments to investigate varied lattice design, fabrication, and material combinations using stereolithography printing with a biocompatible polymer. Mechanical testing demonstrates that a higher ultraviolet curing time increases elastic modulus. Material testing demonstrated that anisotropy does not strongly influence lattice mechanics. Designs were altered by comparing homogenous lattices of single unit cell types and heterogeneous lattices that combine two types of unit cells. Unit cells for heterogeneous structures include a Cube design for a high elastic modulus and Cross design for improved shear response. Mechanical testing of three heterogeneous layouts demonstrated how unit cell organization influences mechanical outcomes, therefore enabling the tuning of an elastic modulus that surpasses the law of averages designed for application-dependent mechanical needs. These findings provide a foundation for linking design, process, and material for engineering 3D printed structures with preferred properties, while also facilitating new directions in design automation and optimization.

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