Square spaceframe lattices |
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Square
spaceframe lattices are comprised of a pair of two-way square grid layers that
are |
staggered relative to one another. To repeat, this spaceframe,
called Square-2, can be |
sliced
out of the octet truss parallel to the 100 plane. Doing so splits
the octahedra |
embedded
in the lattice in half thereby exposing their square shaped cross-sections.
The |
. |
 |
 |
click image to enlarge |
Fig. 250 - Staggering of square |
Fig. 251 - Square-2 spaceframe (red) |
grid layers |
sliced out of the octet truss |
|
. |
struts
comprising the web members of the spaceframe form oblique angles with the |
staggered grids thereby triangulating the structure. |
. |
Square-2 spaceframe: (self dual
tessellation - two-way square grid staggered over two-way |
square grid) |
. |
The
Square-2 lattice design is the most common spaceframe structure in use
today. |
. |
 |
 |
 |
click image to enlarge |
a) outer grid (looking
down) |
b) inner grid (looking up) |
c) strut diagram |
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Fig. 252 - Square-2 spaceframe
[demonstration model built from small
triangles (ST) ]* |
* can also be built with IT or LT |
|
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The
Square-2 cell is inherently unstable due to the square shaped openings in
the grids. |
. |
|
 |
 |
Fig. 253 - Stability analysis of |
the Square-2 unit cell |
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(demonstration model) |
click mage to enlarge |
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a) M = 11 J = 6 |
b) M = 12 J = 6 |
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11 < 3 ( 6 ) - 6 unstable |
12 = 3 ( 6 ) - 6 stable |
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to Knowhere |
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Page 142
- Building stability - Square spaceframe lattices |
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