scholarly journals Erratum: Corrigendum: 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Maiti ◽  
W. Small ◽  
J. P. Lewicki ◽  
T. H. Weisgraber ◽  
E. B. Duoss ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Cellular Solid ◽  
3D Printed

scholarly journals 3D printed cellular solid outperforms traditional stochastic foam in long-term mechanical response

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Maiti ◽  
W. Small ◽  
J. P. Lewicki ◽  
T. H. Weisgraber ◽  
E. B. Duoss ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Mechanical Performance ◽  
Compressive Strain ◽  
Mechanical Strain ◽  
Element Analysis ◽  
Cellular Solid ◽  
3D Printed ◽  
Long Term Performance ◽  
Term Performance

Abstract 3D printing of polymeric foams by direct-ink-write is a recent technological breakthrough that enables the creation of versatile compressible solids with programmable microstructure, customizable shapes, and tunable mechanical response including negative elastic modulus. However, in many applications the success of these 3D printed materials as a viable replacement for traditional stochastic foams critically depends on their mechanical performance and micro-architectural stability while deployed under long-term mechanical strain. To predict the long-term performance of the two types of foams we employed multi-year-long accelerated aging studies under compressive strain followed by a time-temperature-superposition analysis using a minimum-arc-length-based algorithm. The resulting master curves predict superior long-term performance of the 3D printed foam in terms of two different metrics, i.e., compression set and load retention. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material, which might explain the latter’s improved long-term stability and mechanical performance.

scholarly journals A millifluidic chip for cultivation of fish embryos and toxicity testing fabricated by 3D printing technology

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20507-20518
Author(s):  
Petr Panuška ◽  
Zuzana Nejedlá ◽  
Jiří Smejkal ◽  
Petr Aubrecht ◽  
Michaela Liegertová ◽  
...  
Keyword(s):  
3D Printing ◽  
Toxicity Testing ◽  
Toxicity Screening ◽  
Printing Technology ◽  
3D Printing Technology ◽  
Fish Embryos ◽  
3D Printed ◽  
Novel Design

A novel design of 3D printed zebrafish millifluidic system for embryonic long-term cultivation and toxicity screening has been developed. The chip unit provides 24 cultivation chambers and a selective individual embryo removal functionality.

scholarly journals Recurrent contracted sockets treated with personalized, three-dimensionally printed conformers and buccal grafts

2021 ◽  
pp. 112067212110000
Author(s):  
Annabel LW Groot ◽  
Jelmer S Remmers ◽  
Roel JHM Kloos ◽  
Peerooz Saeed ◽  
Dyonne T Hartong
Keyword(s):  
Three Dimensional ◽  
Case Series ◽  
Secondary Outcome ◽  
Retrospective Case ◽  
Upper Eyelid ◽  
Ocular Prosthesis ◽  
Buccal Mucosal Graft ◽  
Custom Made ◽  
3D Printed

Purpose: Recurrent contracted sockets are complex situations where previous surgeries have failed, disabling the wear of an ocular prosthesis. A combined method of surgery and long-term fixation using custom-made, three-dimensional (3D) printed conformers is evaluated. Methods: Retrospective case series of nine patients with recurrent excessive socket contraction and inability to wear a prosthesis, caused by chemical burns ( n = 3), fireworks ( n = 3), trauma ( n = 2) and enucleation and radiotherapy at childhood due to optic nerve glioma ( n = 1) with three average previous socket surgeries (range 2–6). Treatment consisted of a buccal mucosal graft and personalized 3D-printed conformer designed to be fixated to the periosteum and tarsal plates for minimal 2 months. Primary outcome was the retention of an ocular prosthesis. Secondary outcome was the need for additional surgeries. Results: Outcomes were measured at final follow-up between 7 and 36 months postoperatively (mean 20 months). Eight cases were able to wear an ocular prosthesis after 2 months. Three cases initially treated for only the upper or only the lower fornix needed subsequent surgery for the opposite fornix for functional reasons. Two cases had later surgery for cosmetic improvement of upper eyelid position. Despite pre-existing lid abnormalities (scar, entropion, lash deficiency), cosmetic outcome was judged highly acceptable in six cases because of symmetric contour and volume, and reasonably acceptable in the remaining two. Conclusions: Buccal mucosal transplant fixated with a personalized 3D-designed conformer enables retention of a well-fitted ocular prosthesis in previously failed socket surgeries. Initial treatment of both upper and lower fornices is recommended to avoid subsequent surgeries for functional reasons.

scholarly journals Simulation of long-term thermo-mechanical response of clay using an advanced constitutive model

2018 ◽  
Vol 14 (2) ◽  
pp. 295-311 ◽  
Author(s):  
Despina M. Zymnis ◽  
Andrew J. Whittle ◽  
Xiaohui Cheng
Keyword(s):  
Constitutive Model ◽  
Mechanical Response

Deconstructing the Anterior Cruciate Ligament: What We Know and Do Not Know About Function, Material Properties, and Injury Mechanics

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Scott G. McLean ◽  
Kaitlyn F. Mallett ◽  
Ellen M. Arruda
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Joint ◽  
Mechanical Response ◽  
Cruciate Ligament ◽  
Complex Structure ◽  
Acute Injury ◽  
Research Attention ◽  
Increased Risk ◽  
Anterior Cruciate

Anterior cruciate ligament (ACL) injury is a common and potentially catastrophic knee joint injury, afflicting a large number of males and particularly females annually. Apart from the obvious acute injury events, it also presents with significant long-term morbidities, in which osteoarthritis (OA) is a frequent and debilitative outcome. With these facts in mind, a vast amount of research has been undertaken over the past five decades geared toward characterizing the structural and mechanical behaviors of the native ACL tissue under various external load applications. While these efforts have afforded important insights, both in terms of understanding treating and rehabilitating ACL injuries; injury rates, their well-established sex-based disparity, and long-term sequelae have endured. In reviewing the expanse of literature conducted to date in this area, this paper identifies important knowledge gaps that contribute directly to this long-standing clinical dilemma. In particular, the following limitations remain. First, minimal data exist that accurately describe native ACL mechanics under the extreme loading rates synonymous with actual injury. Second, current ACL mechanical data are typically derived from isolated and oversimplified strain estimates that fail to adequately capture the true 3D mechanical response of this anatomically complex structure. Third, graft tissues commonly chosen to reconstruct the ruptured ACL are mechanically suboptimal, being overdesigned for stiffness compared to the native tissue. The net result is an increased risk of rerupture and a modified and potentially hazardous habitual joint contact profile. These major limitations appear to warrant explicit research attention moving forward in order to successfully maintain/restore optimal knee joint function and long-term life quality in a large number of otherwise healthy individuals.

scholarly journals On the development of instabilities in an annulus and a shell composed of a poro-hyperelastic material

2018 ◽  
Vol 474 (2218) ◽  
pp. 20180239 ◽  
Author(s):  
A. P. S. Selvadurai ◽  
A. P. Suvorov
Keyword(s):  
Soft Tissues ◽  
Mechanical Response ◽  
Numerical Solutions ◽  
Pore Space ◽  
Stability Loss ◽  
Computational Approach ◽  
Hyperelastic Material ◽  
Porous Skeleton ◽  
Internal Pressures

The paper investigates the development of instability in an internally pressurized annulus of a poro-hyperelastic material. The theory of poro-hyperelasticity is proposed as an approach for modelling the mechanical behaviour of highly deformable elastic materials, the pore space of which is saturated with a fluid. The consideration of coupling between the mechanical response of the hyperelastic porous skeleton and the pore fluid is important when applying the developments to soft tissues encountered in biomechanical applications. The paper examines the development of an instability in a poro-hyperelastic annulus subjected to internal pressure. Using a computational approach, numerical solutions are obtained for the internal pressures that promote either short-term or long-term instability in a poro-hyperelastic annulus and a poro-hyperelastic shell. In addition, time-dependent effects of stability loss are examined. The analytical solutions are used to benchmark the accuracy of the computational approach.

scholarly journals Long-Term Behavior of Coarse-Grained Rockfill Material and Their Constitutive Modeling

2021 ◽  
Author(s):  
Erich Bauer
Keyword(s):  
Mechanical Response ◽  
Coarse Grained ◽  
Geological Condition ◽  
Dam Foundation ◽  
Solid Hardness ◽  
Rockfill Materials ◽  
Materials Used ◽  
Creep And Stress Relaxation ◽  
Long Term Behavior

For the long-term behavior and safety assessment of rockfill dams, not only the shape of the dam body, the loading history, the geological condition of the dam foundation and abutments, the assessment of possible seismic hazards and seepage events caused by defects of the sealing are important, but also the time dependent mechanical behavior of the dam materials used can be of significant influence. In this paper a novel hypoplastic constitutive model for moisture sensitive, coarse-grained rockfill materials is presented. In the constitutive equations, the so-called solid hardness is a key parameter to reflect the influence of the state of weathering on the mechanical response. With respect to the evolution equation for the solid hardness, creep and stress relaxation can be modeled for dry and wet states of the material in a unified manner. The performance of the model is demonstrated by comparing the numerical simulation with experimental data.

scholarly journals Long-lasting impact of starvation experience on fly activity and place preference

2020 ◽  
Author(s):  
Deepthi Mahishi ◽  
Tilman Triphan ◽  
Ricarda Hesse ◽  
Wolf Huetteroth
Keyword(s):  
Activity Patterns ◽  
Petri Dish ◽  
Sensory Stimulation ◽  
Place Preference ◽  
Substrate Layer ◽  
Hunger Motivation ◽  
Internal States ◽  
3D Printed ◽  
Integration Strategies

AbstractAnimal behaviours are demonstrably governed by sensory stimulation, previous experience and internal states like hunger. With increasing hunger, priorities shift towards foraging and feeding. During foraging, flies are known to employ efficient path integration strategies. However, general long-term activity patterns for both hungry and satiated flies in conditions of foraging remain to be better understood. Similarly, little is known about how chronic contact chemosensory stimulation affects locomotion. To address these questions, we have developed a novel, simplistic fly activity tracking setup – the Panopticon. Using a 3D-printed Petri dish inset, our assay allows recording of walking behaviour, of several flies in parallel, with all arena surfaces covered by a uniform substrate layer. We tested two constellations of providing food: i) in single patches, and ii) omnipresent within the substrate layer. Fly tracking is done with FIJI, further assessment, analysis and presentation is done with a custom-built MATLAB analysis framework. We find that starvation history leads to a long-lasting reduction in locomotion, as well as a delayed place preference for food patches not driven by immediate hunger motivation.

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).

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