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Duke DJ, Clarke AL, Stephens AL, Djumas L, Gregory SD. A computational fluid dynamics assessment of 3D printed ventilator splitters and restrictors for differential multi-patient ventilation. 3D Print Med 2022; 8:2. [PMID: 34985624 PMCID: PMC8727976 DOI: 10.1186/s41205-021-00129-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The global pandemic of novel coronavirus (SARS-CoV-2) has led to global shortages of ventilators and accessories. One solution to this problem is to split ventilators between multiple patients, which poses the difficulty of treating two patients with dissimilar ventilation needs. A proposed solution to this problem is the use of 3D-printed flow splitters and restrictors. There is little data available on the reliability of such devices and how the use of different 3D printing methods might affect their performance. METHODS We performed flow resistance measurements on 30 different 3D-printed restrictor designs produced using a range of fused deposition modelling and stereolithography printers and materials, from consumer grade printers using polylactic acid filament to professional printers using surgical resin. We compared their performance to novel computational fluid dynamics models driven by empirical ventilator flow rate data. This indicates the ideal performance of a part that matches the computer model. RESULTS The 3D-printed restrictors varied considerably between printers and materials to a sufficient degree that would make them unsafe for clinical use without individual testing. This occurs because the interior surface of the restrictor is rough and has a reduced nominal average diameter when compared to the computer model. However, we have also shown that with careful calibration it is possible to tune the end-inspiratory (tidal) volume by titrating the inspiratory time on the ventilator. CONCLUSIONS Computer simulations of differential multi patient ventilation indicate that the use of 3D-printed flow splitters is viable. However, in situ testing indicates that using 3D printers to produce flow restricting orifices is not recommended, as the flow resistance can deviate significantly from expected values depending on the type of printer used. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- Daniel J. Duke
- Department of Mechanical & Aerospace Engineering, Monash University, Clayton, 3800 Victoria Australia
| | - Alexander L. Clarke
- Department of Anaesthesia, Royal Women’s Hospital, Parkville, 3052 Victoria Australia
- Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, 3052 Victoria Australia
| | - Andrew L. Stephens
- CardioRespiratory Engineering and Technology Laboratory (CREATElab), Baker Heart and Diabetes Institute, Melbourne, 3004 Victoria Australia
| | - Lee Djumas
- Department of Materials Engineering, Monash University, Clayton, 3800 Victoria Australia
| | - Shaun D. Gregory
- Department of Mechanical & Aerospace Engineering, Monash University, Clayton, 3800 Victoria Australia
- CardioRespiratory Engineering and Technology Laboratory (CREATElab), Baker Heart and Diabetes Institute, Melbourne, 3004 Victoria Australia
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Landry SA, Mann DL, Djumas L, Messineo L, Terrill PI, Thomson LDJ, Beatty CJ, Hamilton GS, Mansfield D, Edwards BA, Joosten SA. Laboratory performance of oronasal CPAP and adapted snorkel masks to entrain oxygen and CPAP. Respirology 2020; 25:1309-1312. [PMID: 32748429 PMCID: PMC7436923 DOI: 10.1111/resp.13922] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/19/2020] [Accepted: 07/06/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Shane A Landry
- Department of Physiology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia
| | - Dwayne L Mann
- Department of Physiology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia.,School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD, Australia
| | - Lee Djumas
- Woodside Innovation Centre, Department of Materials Science and Engineering, Monash University, Melbourne, VIC, Australia
| | - Ludovico Messineo
- Adelaide Institute for Sleep Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Adelaide, SA, Australia
| | - Philip I Terrill
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD, Australia
| | - Luke D J Thomson
- Department of Physiology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Caroline J Beatty
- Department of Physiology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Garun S Hamilton
- Monash Lung and Sleep, Monash Medical Centre, Melbourne, VIC, Australia.,School of Clinical Sciences, Monash University, Melbourne, VIC, Australia.,Monash Partners - Epworth, Melbourne, VIC, Australia
| | - Darren Mansfield
- Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia.,Monash Lung and Sleep, Monash Medical Centre, Melbourne, VIC, Australia.,Monash Partners - Epworth, Melbourne, VIC, Australia
| | - Bradley A Edwards
- Department of Physiology, School of Biomedical Sciences and Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia.,Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia
| | - Simon A Joosten
- Monash Lung and Sleep, Monash Medical Centre, Melbourne, VIC, Australia.,School of Clinical Sciences, Monash University, Melbourne, VIC, Australia.,Monash Partners - Epworth, Melbourne, VIC, Australia
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Djumas L, Simon GP, Estrin Y, Molotnikov A. Deformation mechanics of non-planar topologically interlocked assemblies with structural hierarchy and varying geometry. Sci Rep 2017; 7:11844. [PMID: 28928369 PMCID: PMC5605519 DOI: 10.1038/s41598-017-12147-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/04/2017] [Indexed: 12/20/2022] Open
Abstract
Structural hierarchy is known to enhance the performance of many of Nature's materials. In this work, we apply the idea of hierarchical structure to topologically interlocked assemblies, obtained from measurements under point loading, undertaken on identical discrete block ensembles with matching non-planar surfaces. It was demonstrated that imposing a hierarchical structure adds to the load bearing capacity of topological interlocking assemblies. The deformation mechanics of these structures was also examined numerically by finite element analysis. Multiple mechanisms of surface contact, such as slip and tilt of the building blocks, were hypothesised to control the mechanical response of topological interlocking assemblies studied. This was confirmed using as a model a newly designed interlocking block, where slip was suppressed, which produced a gain in peak loading. Our study highlights the possibility of tailoring the mechanical response of topological interlocking assemblies using geometrical features of both the element geometry and the contact surface profile.
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Affiliation(s)
- Lee Djumas
- Department of Materials Science and Engineering and New Horizons Research Centre, Monash University, Victoria, 3800, Australia.
| | - George P Simon
- Department of Materials Science and Engineering and New Horizons Research Centre, Monash University, Victoria, 3800, Australia
| | - Yuri Estrin
- Department of Materials Science and Engineering and New Horizons Research Centre, Monash University, Victoria, 3800, Australia
- Laboratory of Hybrid Nanostructured Materials, National University of Science and Technology "MISIS", Leninsky prospect 4, 119049, Moscow, Russia
| | - Andrey Molotnikov
- Department of Materials Science and Engineering and New Horizons Research Centre, Monash University, Victoria, 3800, Australia.
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Djumas L, Molotnikov A, Simon GP, Estrin Y. Enhanced Mechanical Performance of Bio-Inspired Hybrid Structures Utilising Topological Interlocking Geometry. Sci Rep 2016; 6:26706. [PMID: 27216277 PMCID: PMC4877644 DOI: 10.1038/srep26706] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/05/2016] [Indexed: 01/24/2023] Open
Abstract
Structural composites inspired by nacre have emerged as prime exemplars for guiding materials design of fracture-resistant, rigid hybrid materials. The intricate microstructure of nacre, which combines a hard majority phase with a small fraction of a soft phase, achieves superior mechanical properties compared to its constituents and has generated much interest. However, replicating the hierarchical microstructure of nacre is very challenging, not to mention improving it. In this article, we propose to alter the geometry of the hard building blocks by introducing the concept of topological interlocking. This design principle has previously been shown to provide an inherently brittle material with a remarkable flexural compliance. We now demonstrate that by combining the basic architecture of nacre with topological interlocking of discrete hard building blocks, hybrid materials of a new type can be produced. By adding a soft phase at the interfaces between topologically interlocked blocks in a single-build additive manufacturing process, further improvement of mechanical properties is achieved. The design of these fabricated hybrid structures has been guided by computational work elucidating the effect of various geometries. To our knowledge, this is the first reported study that combines the advantages of nacre-inspired structures with the benefits of topological interlocking.
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Affiliation(s)
- Lee Djumas
- Department of Materials Science and Engineering Monash University, Victoria, 3800, Australia
| | - Andrey Molotnikov
- Department of Materials Science and Engineering Monash University, Victoria, 3800, Australia
| | - George P. Simon
- Department of Materials Science and Engineering Monash University, Victoria, 3800, Australia
| | - Yuri Estrin
- Department of Materials Science and Engineering Monash University, Victoria, 3800, Australia
- Laboratory of Hybrid Nanostructured Materials, NUST MISiS, Moscow 119490 Russia
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