Structural Modelling of Tensegrity Structures

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  • @Jesusbill thanks, seems to be running. Now I need to figure out how it works ;)

    Jesusbill
  • @brunopostle Great! I will make a new thread when I have some time to gather some links to useful resources.

  • edited May 2020

    Tensegrity structure under ground excitation with Code_Aster.
    Input files for this analysis can be found in our dedicated GitHub repo https://github.com/Jesusbill/code-aster-examples/tree/master/TensegritySeismic

    MoultReD_CoDEpaullee
  • @Jesusbill very impressive. This is also my experience with tensegrity structures.

    Jesusbill
  • @brunopostle with the right tools and the right modelling choices, in this case cable elements for cables with no stiffness in compression and large displacements/large rotations analysis settings to satisfy the equilibrium in the deformed configuration, one should be able to simulate the actual, or let's say a realistic, behavior of a structure. In this particular case it is also impressive to watch :) certainly a nice "eye-candy" for Code_Aster

  • @Jesusbill I meant this is my experience with real tensegrity structures

  • Yes I thought so @brunopostle, sounds great. To be honest I didn't know about tensegrity structures until a few months ago.
    I would be curious to know what you have worked on

  • @Jesusbill we never got past the physical mockup stage. Even the most famous tensegrity designs are extremely elastic, we quickly realised from our 2m high models that a 20m high structure wasn't going to be feasible.

  • @brunopostle Yes they look like quite unstable structures by design

  • edited May 2020

    I've heard somewhere (no idea if true) that NASA is very interested in intensegrity structures - because if a space frame could be designed with a tensegrity structure, that would allow very large structures to be fabricated in space, with a much lower weight payload to bring up from Earth, as half the elements are tensile. I also heard how they were considering some form of extruder that would extrude out modules of this tensegrity space frame.

    No idea how that might or might not work, but sounded fascinating to me ;)

  • edited May 2020

    @Moult a solar farm designed in this way and will be implemented in the space by NASA
    However, maybe I'm wrong, but the solvers and the approach you use is not interesting for NASA :)) (A clue: Iso...?)

  • So in space the intensegrity structures would rely on centrifugal force instead of gravity? It does seem like it could be more stable if the forces where radial.

  • Never mind looked it up it. Looks like they where exploring rovers using tensegrity structures.

    paullee
  • Yes, I saw this one too.
    I think gravity doesn't matter because it has a structure that causes always the sum of stresses be zero
    For NASA these kinds of challenges are easy to solve
    I think the main focus is or could be "MATERIALS"

  • @baswein said:
    Looks like they where exploring rovers using tensegrity structures.

    Interesting video, that would be relevant to tensegrity robotics. I even found a relevant GitHub repo https://github.com/NASA-Tensegrity-Robotics-Toolkit/NTRTsim

    @Moult said:
    I've heard somewhere (no idea if true) that NASA is very interested in intensegrity structures

    I did a quick search and came up with this https://www.nasa.gov/feature/tensegrity-approaches-to-in-space-construction-of-a-1g-growable-habitat/. They call it "Growth-Adapted Tensegrity Structures (GATS)" and in some part it says:

    The critical enabling technology for our GATS technology is Tensegrity Engineering, where new design methods, new dynamic models, and new control approaches are specialized for networks of axially-loaded elements, allowing the structural mass to be minimized, while the dynamic response can be controlled with minimal energy, with repairable, growable structural methods, using tractable analytical tools that are now available.

    The fact that they mention that the dynamic response is controlled with minimal energy leads me to think about active control systems, where one for example would alter the tension in the cables real-time and based on a feedback loop of the response of the structure to control and dissipate vibrations, but that's only an interpretation.

    Moultbaswein
  • IGA: Isogeometric analysis is a computational approach that offers the possibility of integrating finite element analysis (FEA) into conventional NURBS-based CAD design tools. Currently, it is necessary to convert data between CAD and FEA packages to analyse new designs during development, a difficult task since the two computational geometric approaches are different. Isogeometric analysis employs complex NURBS geometry (the basis of most CAD packages) in the FEA application directly. This allows models to be designed, tested and adjusted in one go, using a common data set.
    https://en.wikipedia.org/wiki/Isogeometric_analysis

  • @ReD_CoDE it looks like an interesting approach but I have not seen any robust practical applications yet.

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