Example 3: [two-way rectangle (REC) outer grid staggered over
small square (SS) grid] |
. |
 |
 |
 |
click image to enlarge |
a) barrel vault |
b) cylinder |
c) unit cell |
RT (purple), ST (green) |
M = 17 J = 8 |
Fig. 282 - Arched spaceframes - 3
(demonstration models) |
17 < 3 ( 8 ) - 6, needs + 1 M |
|
|
Example 4: [two-way rectangle (REC) outer grid over two-way
small square (SS) grid] |
. |
 |
 |
 |
click image to enlarge |
a) barrel vault |
b) cylinder |
c) unit cell |
ST (blue), RT (purple), IT (red) |
M = 17 J = 8 |
Fig. 283 - Arched spaceframes - 4
(demonstration models) |
17 < 3 ( 8 ) - 6, needs + 1 M |
|
|
Hyperboloid cylinders |
. |
Thus far
we have been concerned with how to stabilize spaceframes. However,
intriguing |
structures can also be created by intentionally destabilizing lattices.
For example, the |
rhombohedral unit cell of the Tri-1 lattice can be modified slightly by
removing one of its |
struts
as shown on the next page (Fig. 285). The spaceframe built from it
can be flexed |
into the
model of a curved structure called a hyperboloid cylinder. |
. |
 |
Fig. 284 - Hyperboloid cylinder |
 |
◄ flexing in |
overhead view ► |
(built from all LT or ST) |
(demonstration model) |
click image to enlarge |
|
. |
The
contour of this model depends on the way that it is flexed. Flexing
it so that the grid |
with the
missing struts faces inwards results in the narrow diameter hyperboloid
above. |
. |
Back
to Knowhere |
 |
Page 151
- Building stability - Hyperboloid cylinders |
 |
|