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Re: Trains and stacks of narrow-spread tether set

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  • roderickjosephread
    OK on the array front... Today my mission is a new kinda sketch... I think A kite array with piezoelectric multilayer bending actuators. The array is going to
    Message 1 of 15 , Sep 27, 2011
      OK on the array front...
      Today my mission is a new kinda sketch... I think

      A kite array with piezoelectric multilayer bending actuators. The array is going to be 3d.
      Each kite will have one or more piezoelectric multilayer bending actuators.
      The top layer of the array will be set out and addressed as per VGA (yes video) standards. e.g. a printed cut set of micro kite ribbons glued side by side with...
      Below each node will hang a reciprocally vibrating fish tail ribbon(as per Dave S design) At the bottom of each tail will be Piezoelectric energy harvesting circuits.
      below that will be a kite layer
      below that will be a generator layer
      ...

      I am concerned that "Particular attention must always be paid to ensuring that the mechanical strain arising during deformation of the piezoceramic shows the same orientation overall" http://www.piezoproducts.com/index.php?id=144&L=0

      In a stable array like this though... Up is the average tension vector.

      I'm pretty sure this can be done.
      Phew back to electronics at last my home turf....
      probably where I'll go furthest wrong
    • roderickjosephread
      Actually A tall wide shallow (shallow downwind single kite even) array is probably better than say a 640 (wide) x 480 (deep downwind) vga x tall standard.
      Message 2 of 15 , Sep 27, 2011
        Actually
        A tall wide shallow (shallow downwind single kite even) array is probably better than say a 640 (wide) x 480 (deep downwind) vga x tall standard.

        Makes more sense ... downwind kites would all suffer wind shaddow ... but would add to structural redundancy and stability of mesh...

        Single front array of kites with tails downwind can be print cut easily though.
        And it will make for easy back attachment of generator wings using a reel to scroll the kite print sheet ... alligning the gen strings between the kite cuts at the back... yep that's it
        ok off to draw
      • roderickjosephread
        Sketch should now be in the photos section ... if not it s on my site. Anyone know a good large scale rolling, cutting, seeming process facilities engineer?
        Message 3 of 15 , Sep 27, 2011
          Sketch should now be in the photos section ...
          if not it's on my site.

          Anyone know a good large scale rolling, cutting, seeming process facilities engineer?
          Have been asking piezo folks about in-line stringing. awaiting response.
        • Bob Stuart
          Kite design is one of the most weight-sensitive jobs in engineering, so I would like to recommend the works of J.E. Gordon as being by far the easiest way to
          Message 4 of 15 , Sep 27, 2011
            Kite design is one of the most weight-sensitive jobs in engineering,
            so I would like to recommend the works of J.E. Gordon as being by far
            the easiest way to get a sense for what approaches tend to work, and
            why. Rather than start right off with definitions and math, he tells
            the story of the first students of science to come to an
            understanding of what was going on all around them. In particular,
            "Structures" has a chapter on designing for minimum weight that
            explains why faster airplanes always have fewer wires and struts
            exposed. Large, lightly loaded artifacts can only be made
            efficiently if based on tension structures for a few inescapable
            mathematical reasons, and he explains them in excellent, entertaining
            english. Did you know that the "bicycle" wheel was actually invented
            for an attempt at an airplane around 1850? The actual math is very
            simple, but he keeps it to just a few handy formulas in the appendix
            for those who want to start serious calculations. With a good
            understanding of the forces at work, a few operations on a basic
            calculator can tell you how light you can go on any particular
            member, closer than the usual range for selection.

            Best,
            Bob Stuart
          • Joe Faust
            Forum members are invited to add links to the folder: Structural design for kite systems
            Message 5 of 15 , Sep 27, 2011

              Forum members are invited to add links to the folder:

              Structural design for kite systems

              and add sub-folders that fit your focus, if needed.

            • Muzhichkov
              A bicycle wheel with spokes from rope, by the way, can be a good idea for light turbine.
              Message 6 of 15 , Sep 27, 2011
                A bicycle wheel with spokes from rope, by the way, can be a good idea for light turbine.
              • dave santos
                Rod,   A Forum conclusion from years back is that conventional piezo is not a practical basis for AWE. The main reason is inefficiency in driving an
                Message 7 of 15 , Sep 27, 2011
                  Rod,
                   
                  A Forum conclusion from years back is that conventional piezo is not a practical basis for AWE. The main reason is inefficiency in driving an inherently high-frequency (~10000hz) technology like thin-film piezo at far lower kite motion frequencies (~1hz). An exception is to somehow create the high frequency mechanical resonance to tap. Bulk piezo character of a megascale AWE latticework is of course based on different principles, where the frequency match is natural.
                   
                  Other objections to thin piezo relate to availability, capital cost, complex interconnects, durability, etc.. Far better to just use rag and conventional generators, for now,
                   
                  daveS

                   
                • Bob Stuart
                  A bicycle wheel is a wonderfully efficient design for its purpose, and can benefit from Kevlar spokes. If you have a bike wheel and want to cobble together a
                  Message 8 of 15 , Sep 28, 2011
                    A bicycle wheel is a wonderfully efficient design for its purpose, and can benefit from Kevlar spokes.  If you have a bike wheel and want to cobble together a small generator, it can save time.  However, as a turbine design, it leaves much to be desired.  The spokes encourage a high-solidity disk, which is mostly superfluous.  The rim, like other ducts, is material that would do more good adding to the swept area.  A few designs take advantage of the high rim speed to improve transmission efficiency, but this comes at the cost of bearing complexity and friction.  

                    Bob Stuart

                    On 27-Sep-11, at 1:55 PM, Muzhichkov wrote:

                    A bicycle wheel with spokes from rope, by the way, can be a good idea for light turbine.


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