mechnificent sea horse. why does sea horse tails are squares, instead of circular in cross-sectional area

1. Why seahorse tails are
square?
Science Engineering Inspired by Nature
SIF2004/SMES2204 MECHANICS
GROUP ASSIGNMENT & Soft Skill Assessment
SEM I 2017/2018
(Prof. Sithi V Muniandy)

2. P1. Forces- bioinspired mechanics
Name Matric No Role
Nor Fadilah binti Pikau SIF160060 Project Designer & Technical
Aina Izzati binti Mat Dah SIF160004 Technical Team
Muhammad Hussin bin Abdul Jabar IIS150012 Technical Team
Che Sulaiman Muttaqin bin Che Umar IIS150003 Technical Team
Sanjeev Raj A/L Gopal SEM150057 Technical Team
Muhammad Shahrul Arif bin Adi Rumi SIF160050 Science Communicator & Logistic/Planning
Group members:

4. Introduction
• Seahorses do not use their tails for swimming because they lack a caudal fin.
• Instead, it acts as:
1. Flexible prehensile appendages that allow them to hide and or withstand
predators’ high impact and crushing pressure jaws.
2. Capture prey by anchoring to objects such as seagrasses, mangrove roots,
and coral reef.

5. Experimental data of
the seahorse tail design
• An assistant professor of robotics at Oregon State University, Ross Hatton
and his team ran experiments by creating 3-D printed models of square and
round structures. This gave the team a point of comparison for testing the
square tail’s abilities.
Michael M. P., Dominique A., Ross L. H., Marc A. M., Joanna M. . (3 July 2015).
Why the seahorse tail is square. sciencemag.org, 349(6243), 46-52.
doi:10.1126/science.aaa6683

6. Fig. 1 Seahorse skeletons are composed of
highly articulated bony plates that surround
a central vertebral column.

8. • the square prototype
returns to its linearly
aligned resting position
after impact
• Whereas the cylindrical
one remains partially
deformed and
misaligned
Fig. 6. Impact and crushing performance of the prototypes.
• Images of the square (A) and cylindrical (B) prototypes subject to impact by a rubber mallet.
• Models of the artificial skeletons (left) and representative schematics of solid rings (right) subject to
transverse uniaxial and transverse biaxial compression, showing the locations of primary and
secondary plastic hinges with red arrows in (C) and (D) and red dots in (E) and (F).
• All units are in millimeters.

9. Fig. 7 Unilateral compression of the prototypes
and solid rings.
• (A) Plot of the compressive load versus normalized displacement for
the square (black) and cylindrical (blue) prototypes subject to
unilateral compression between two rigid plates. The solid lines
correspond to direct experimental measurements, and the dashed
lines correspond to theoretical predictions of load and displacement
from Eqs. 2 and 3.
• (B and C) Images of the square (top) and cylindrical (bottom)
prototypes subject to transverse unilateral compression just before
strut disjoining, corresponding to the red arrows in (A).
• (D) Plot of the compressive load versus normalized displacement for
a square (black dashed line) and circular (blue dashed-dotted line)
solid ring subject to transverse unilateral compression between two
rigid plates.
• (E) Magnified plot illustrating the elastic region and yield points of
the load-displacement curves in (D).
• (F and G) Images of the square (top) and circular (bottom) solid rings
subject to transverse unilateral compression just before fracture,
corresponding to the red arrows in (D).

11. Compression and the real skeletal structure of the
seahorse
• while the cylindrical tail gets smooshed and damaged if enough force is applied,
• the square tail flattens out by allowing its bony plates to slide past each other,
deflecting damage away from the vertebral column and giving it the ability to
absorb more energy before it is broken.

12. Gripping
• The square tail compared to
cylindrical, enjoys more contact
points with the surfaces it grabs
onto, allowing it to be a more
dexterous gripping device.
Figure 9 : Models of the cylindrical tail (left)
and the square-prism tail.
(Michael M Porter, Clemson University)