Page 386 - Control Theory in Biomedical Engineering

352 Control theory in biomedical engineering

Fig. 34 (A) Waterbomb base crease. (B) Simple waterbomb structure.

It is possible to obtain a more complex geometry that displays much
more interesting properties by tessellating the base by n m units over a rect-
angle and with each alternating row (or column) having the waterbomb base
phase shifted by 180degrees. For the two-dimensional base that can be
approximated into a circular cylinder with smooth curvature, a minimum
of six rows is required, if the cylinder is rolled along its length. The crease
pattern and the completed structure is shown in Fig. 35. Furthermore, this
origami structure is made up of a variant of the hexagonal re-entrant struc-
ture and hence can display interesting auxetic behavior (Fig. 36).
The waterbomb cylinder has recently received much interest recently,
especially with respect to practical applications like stent grafts. However,

Fig. 35 (A) Waterbomb tessellating crease. (B) Waterbomb phase shifts. (C) Completed
waterbomb tube.