scholarly journals Fish-inspired flexible protective material systems with anisotropic bending stiffness

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katia Zolotovsky ◽  
Swati Varshney ◽  
Steffen Reichert ◽  
Eric M. Arndt ◽  
Ming Dao ◽  
...  
Keyword(s):  
Material Properties ◽  
Mechanical Anisotropy ◽  
Design Strategies ◽  
Protective Material ◽  
Design Rules ◽  
Complex Shapes ◽  
Material Systems ◽  
3D Printed ◽  
Polypterus Senegalus ◽  
Protective Systems

AbstractBiological structures integrate morphometry (shape-based rules) with materials design to maximize organism survival. The exoskeleton of the armored fish, Polypterus senegalus, balances flexibility with protection from predatory and territorial threats. Material properties of the exoskeleton are known; however, the geometric design rules underlying its anisotropic flexibility are uncharacterized. Here, we show how scale shape, articulation, and composite architecture produce anisotropic mechanics using bio-inspired, multi-material 3D-printed prototypes. Passive loading (draping) shows that compliant connections between the scales contribute to mechanical anisotropy. Simulated and experimental active loading (bending) show orientation-dependent stiffness ranging over orders of magnitude, including ‘mechanical invisibility’ of the scales where they do not add stiffness to the exoskeleton. The results illustrate how morphometry provides a powerful tool to tune flexibility in composite architectures independent of varying constituent materials composition. We anticipate that introducing morphometric design strategies will enable flexible, protective systems tuned to complex shapes and functions.

Effects of infill patterns on the strength and stiffness of 3D printed topologically optimized geometries

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nadim S. Hmeidat ◽  
Bailey Brown ◽  
Xiu Jia ◽  
Natasha Vermaak ◽  
Brett Compton
Keyword(s):  
Material Properties ◽  
Failure Modes ◽  
Mechanical Anisotropy ◽  
Failure Behavior ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Orthotropic Composite ◽  
Material Extrusion ◽  
Specific Material ◽  
Strength And Stiffness

Purpose Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM. Design/methodology/approach A benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens. Findings Experiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures. Originality/value This study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.

Simplified LBB Guidance: Stage 1 — Development of a New Software Tool and Initial Scoping Calculations

2018 ◽  
Author(s):  
Peter Gill ◽  
John Sharples ◽  
Chris Aird
Keyword(s):  
Fracture Toughness ◽  
Material Properties ◽  
Software Tool ◽  
Pipe Material ◽  
Loading Conditions ◽  
Design Rules ◽  
Inner Radius ◽  
Inner Diameter ◽  
Stage 1 ◽  
Leak Before Break

This study is focussed on establishing more simplified Leak-before-Break (LbB) guidance for inclusion into Section III.11 of the R6 procedure. The approach adopted has involved the development of a universal software tool for LbB simplified assessments which can be used to perform initial scoping calculations to demonstrate typical LbB cases. It is envisaged that this simplified methodology will enable plant assessment engineers to be more informed on which sites on plant are likely to have LbB successfully applied and to be able to undertake LbB assessments in a more simplistic way than is currently available. Using the developed software tool, a range of LbB calculations for different cracks and loading conditions have been performed to provide guidance on where LbB is more likely to be applied on plant. Loading conditions include primary and secondary stresses, where through-wall changes have been accounted for. The pipe geometries included in this study have been defined by the inner radius and the wall thickness, calculated by minimum pipe thickness required according to meet the design rules of ASME III. The pipe inner radius varies from 40mm to 200mm (80mm to 400mm inner diameter (ID)). All pipe outer diameters are less than 0.5m. All cracks considered in this study are through-wall and circumferential. Pipe material properties are chosen to be broadly representative of an Austenitic Stainless Steel, where the fracture toughness varies from 100 to 180MPa√m and the yield stress is 150MPa.

scholarly journals 3D Printed Chromophoric Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 317
Author(s):  
Zachary Brounstein ◽  
Jarrod Ronquillo ◽  
Andrea Labouriau
Keyword(s):  
Thermal Stability ◽  
3D Printing ◽  
Material Properties ◽  
Chemical Structure ◽  
Elevated Temperatures ◽  
Advanced Manufacturing ◽  
Color Changes ◽  
Printed Sensors ◽  
3D Printed ◽  
Manufacturing Techniques

Eight chromophoric indicators are incorporated into Sylgard 184 to develop sensors that are fabricated either by traditional methods such as casting or by more advanced manufacturing techniques such as 3D printing. The sensors exhibit specific color changes when exposed to acidic species, basic species, or elevated temperatures. Additionally, material properties are investigated to assess the chemical structure, Shore A Hardness, and thermal stability. Comparisons between the casted and 3D printed sensors show that the sensing devices fabricated with the advanced manufacturing technique are more efficient because the color changes are more easily detected.

scholarly journals Microstructural Control of Polymers Achieved Using Controlled Phase Separation During 3D Printing with Oligomer Libraries: Dictating Drug Release for Personalized Subdermal Implants

2020 ◽  
Author(s):  
Laura Ruiz-Cantu ◽  
Gustavo Trindade ◽  
Vincenzo Taresco ◽  
Zuoxin Zhou ◽  
Laurence Burroughs ◽  
...  
Keyword(s):  
Phase Separation ◽  
3D Printing ◽  
Drug Release ◽  
Material Properties ◽  
High Throughput Screening ◽  
Ink Jet ◽  
Versatile Tool ◽  
3D Printed ◽  
Subdermal Implants ◽  
Level Of Understanding

<p>Controlling the microstructure of materials by means of phase separation is a versatile tool for optimizing material properties. In this study, we show that ink jet 3D printing of polymer blends gives rise to controllable phase separation that can be used to tailor the release of drugs. We predicted phase separation using high throughput screening combined with a model based on the Flory-Huggins interaction parameter, and were able to show that drug release from 3D printed structures can be predicted from observations based on single drops of mixtures. This new understanding gives us hierarchical compositional control, from droplet to device, allowing release to be ‘dialed up’ without any manipulation of geometry. This is an important advance for implants that need to be delivered by cannula, where the shape is highly constrained and thus the usual geometrical freedoms associated with 3D printing cannot be exploited, bringing a hitherto unseen level of understanding to emergent material properties of 3D printing.</p>

Modeling and Experimental Characterization of Viscoelastic 3D Printed Spring/Damper Systems

2017 ◽  
Author(s):  
Heather L. Lai ◽  
Cuiyu Kuang ◽  
Jared Nelson
Keyword(s):  
Dynamic Behavior ◽  
Material Properties ◽  
Dynamic Properties ◽  
Viscoelastic Materials ◽  
Vibration Isolators ◽  
Damping Behavior ◽  
Wide Range ◽  
3D Printed ◽  
Printed Materials

The development of flexible, viscoelastic materials for consumer 3D printers has provided the opportunity for a wide range of devices with damping behavior such as tuned vibration isolators to be innovatively developed and inexpensively manufactured. However, there is currently little information available about the dynamic behavior of these 3D printed materials necessary for modeling of dynamic behavior prior to print. In order to fully utilize these promising materials, a deeper understanding of the material properties, and the subsequent dynamic behavior is critical. This study evaluates the use of three different types of models: transient response, frequency response and hysteretic response to predict the dynamic behavior of viscoelastic 3D printed materials based on static and dynamic material properties. Models of viscoelastic materials are presented and verified experimentally using two 3D printable materials and two traditional viscoelastic materials. The experimental response of each of the materials shows agreement with the modeled behavior, and underscores the need for improved characterization of the dynamic properties of viscoelastic 3D printable materials.

Characterisation of Cryogenic Material Properties of 3D-Printed Superconducting Niobium using a 3D Lumped Element Microwave Cavity

2020 ◽  
pp. 1-1
Author(s):  
Ben T. McAllister ◽  
Jeremy Bourhill ◽  
Wing Him J. Ma ◽  
Tim Sercombe ◽  
Maxim Goryachev ◽  
...  
Keyword(s):  
Material Properties ◽  
Microwave Cavity ◽  
Lumped Element ◽  
3D Printed

scholarly journals Collagen Structure and Mechanical Properties of the Human Sclera: Analysis for the Effects of Age

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Baptiste Coudrillier ◽  
Jacek Pijanka ◽  
Joan Jefferys ◽  
Thomas Sorensen ◽  
Harry A. Quigley ◽  
...  
Keyword(s):  
Material Properties ◽  
Collagen Fiber ◽  
Image Correlation ◽  
Mechanical Anisotropy ◽  
Matrix Stiffness ◽  
Fiber Structure ◽  
Human Donor ◽  
Full Field ◽  
X Ray Scattering ◽  
The Difference

The objective of this study was to measure the collagen fiber structure and estimate the material properties of 7 human donor scleras, from age 53 to 91. The specimens were subjected to inflation testing, and the full-field displacement maps were measured by digital image correlation. After testing, the collagen fiber structure was mapped using wide-angle X-ray scattering. A specimen-specific inverse finite element method was applied to calculate the material properties of the collagen fibers and interfiber matrix by minimizing the difference between the experimental displacements and model predictions. Age effects on the fiber structure and material properties were estimated using multivariate models accounting for spatial autocorrelation. Older age was associated with a larger matrix stiffness (p = 0.001), a lower degree of fiber alignment in the peripapillary sclera (p = 0.01), and a lower mechanical anisotropy in the peripapillary sclera (p = 0.03).

3D Printed Composites With Continuous Carbon Fiber Reinforcements

2017 ◽  
Author(s):  
Ali N. Sarvestani ◽  
Nekoda van de Werken ◽  
Pouria Khanbolouki ◽  
Mehran Tehrani
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
High Performance ◽  
Mechanical Response ◽  
Failure Mechanisms ◽  
Micro Structure ◽  
Design Rules ◽  
Continuous Carbon Fiber ◽  
Fiber Reinforcements ◽  
3D Printed

Additively manufactured polymers can be reinforced with high-performance reinforcements such as carbon fibers. Printed thermoplastics with embedded continuous carbon fibers are up to two orders of magnitude stronger and stiffer than high-grade 3D printed polymers. In this work, the mechanical response of such 3D printed carbon fiber specimens is evaluated. While the precursor carbon fiber reinforced filaments achieve a stiffness of 50GPa and strength 700MPa, mechanical properties of their printed parts are highly affected by printed carbon fiber curvatures. In this work, the structure of 3D printed parts was examined, and some design rules for 3D printing with continuous carbon fibers are suggested. Moreover, failure mechanisms in these samples are discussed and correlated to the micro-structure of the composites and the carbon fiber configuration.

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