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Building the space elevator: lessons from biological design

One of the biggest perceived challenges in building megastructures, such as the space elevator, is the unavailability of materials with sufficient tensile strength. The presumed necessity of very strong materials stems from a design paradigm which requires structures to operate at a small fraction o...

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Detalles Bibliográficos
Autores principales: Popescu, Dan M., Sun, Sean X.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6228488/
https://www.ncbi.nlm.nih.gov/pubmed/30333242
http://dx.doi.org/10.1098/rsif.2018.0086
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author Popescu, Dan M.
Sun, Sean X.
author_facet Popescu, Dan M.
Sun, Sean X.
author_sort Popescu, Dan M.
collection PubMed
description One of the biggest perceived challenges in building megastructures, such as the space elevator, is the unavailability of materials with sufficient tensile strength. The presumed necessity of very strong materials stems from a design paradigm which requires structures to operate at a small fraction of their maximum tensile strength (usually, 50% or less). This criterion limits the probability of failure by giving structures sufficient leeway in handling stochastic components, such as variability in material strength and/or external forces. While reasonable for typical engineering structures, low working stress ratios—defined as operating stress as a fraction of ultimate tensile strength—in the case of megastructures are both too stringent and unable to adequately control the failure probability. We draw inspiration from natural biological structures, such as bones, tendons and ligaments, which are made up of smaller substructures and exhibit self-repair, and suggest a design that requires structures to operate at significantly higher stress ratios, while maintaining reliability through a continuous repair mechanism. We outline a mathematical framework for analysing the reliability of structures with components exhibiting probabilistic rupture and repair that depend on their time-in-use (age). Further, we predict time-to-failure distributions for the overall structure. We then apply this framework to the space elevator and find that a high degree of reliability is achievable using currently existing materials, provided it operates at sufficiently high working stress ratios, sustained through an autonomous repair mechanism, implemented via, e.g. robots.
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spelling pubmed-62284882018-12-12 Building the space elevator: lessons from biological design Popescu, Dan M. Sun, Sean X. J R Soc Interface Life Sciences–Engineering interface One of the biggest perceived challenges in building megastructures, such as the space elevator, is the unavailability of materials with sufficient tensile strength. The presumed necessity of very strong materials stems from a design paradigm which requires structures to operate at a small fraction of their maximum tensile strength (usually, 50% or less). This criterion limits the probability of failure by giving structures sufficient leeway in handling stochastic components, such as variability in material strength and/or external forces. While reasonable for typical engineering structures, low working stress ratios—defined as operating stress as a fraction of ultimate tensile strength—in the case of megastructures are both too stringent and unable to adequately control the failure probability. We draw inspiration from natural biological structures, such as bones, tendons and ligaments, which are made up of smaller substructures and exhibit self-repair, and suggest a design that requires structures to operate at significantly higher stress ratios, while maintaining reliability through a continuous repair mechanism. We outline a mathematical framework for analysing the reliability of structures with components exhibiting probabilistic rupture and repair that depend on their time-in-use (age). Further, we predict time-to-failure distributions for the overall structure. We then apply this framework to the space elevator and find that a high degree of reliability is achievable using currently existing materials, provided it operates at sufficiently high working stress ratios, sustained through an autonomous repair mechanism, implemented via, e.g. robots. The Royal Society 2018-10 2018-10-17 /pmc/articles/PMC6228488/ /pubmed/30333242 http://dx.doi.org/10.1098/rsif.2018.0086 Text en © 2018 The Authors. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Life Sciences–Engineering interface
Popescu, Dan M.
Sun, Sean X.
Building the space elevator: lessons from biological design
title Building the space elevator: lessons from biological design
title_full Building the space elevator: lessons from biological design
title_fullStr Building the space elevator: lessons from biological design
title_full_unstemmed Building the space elevator: lessons from biological design
title_short Building the space elevator: lessons from biological design
title_sort building the space elevator: lessons from biological design
topic Life Sciences–Engineering interface
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6228488/
https://www.ncbi.nlm.nih.gov/pubmed/30333242
http://dx.doi.org/10.1098/rsif.2018.0086
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