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tentchoirAI and Robotics

Nov 15, 2013 (3 years and 10 months ago)

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THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

REACTION WOODS

INSPIRATION FOR SMART MATERIALS

AND STRUCTURES

George Jeronimidis

Compression

Wood

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett



WHAT IS INTERESTING ABOUT REACTION WOODS ?




IS THERE SOMETHING USEFUL TO LEARN ?




INSPIRATION FOR ENGINEERING SOLUTIONS




CONCLUSIONS

Reaction wood is used by trees to modulate shape of trunk and branches

Why aren’t all trees the shape of weeping willows ?

Adaptive shape change

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Wood microstructure

20
-
30

m
m

Fibres provide the key
organisational elements for
functional self
-
assembly

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Creating functional fibre architectures in plant cell walls

Barnett & Jeronimidis, 2003

Clair, 2001

Cave, 1980

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Physical interactions between cell walls during maturation

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Hygro
-

or thermal expansivity of angle
-
ply structures

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Interesting effects result from
coupled deformations in anisotropic
laminated structures


Neither component in the laminate
(fibres / matrix) has a negative or zero
thermal exapansion coefficient


Yet, the laminate can be designed to
have negative or zero expansivity for
some specified fibre angles

Depending on the microfibrillar orientation in the various cell
walls and their relative thickness, their interactions during
maturation can produce axial shrinkage, axial expansion, radial
shrinkage, radial expansion and twist

Axial contraction in tension wood

Axial expansion in compression wood

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Partial or total suppression of deformation (twist) due to cell
-
cell adhesion =
high internal stresses at interfaces

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Non
-
symmetric laminate

De
-
hydration / Maturation

Shape change (curvature)

normal wood

tension wood

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Differences between reaction wood and normal wood provide mechanism for shape change

Coutand
et al
, 2004

Poplar


Normal Wood

Poplar


Tension Wood

Inspiration for engineering solutions

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Adaptive roof element

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Tension or Compression Wood
“Cell” element

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

“Tissue / Organ” element

Tension wood side

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Tension wood side

Compression wood side

Element combining “tension” and “compression” wood

Stretching
-
Bending

Different materials

Different scale

Different actuation

…………………………….but


SAME FUNCTIONALITY

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

DIFFERENTIATION

AT THE “MATERIAL” LEVEL


(Anisotropy, Heterogeneity, Hierarchies)

FUNCTIONAL INTEGRATION

AT THE “SYSTEM” LEVEL

+

DIFFERENTIATION

AT THE “STRUCTURE” LEVEL


(Shape, Dimensions, Geometry
)

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett

Conclusions

THANK YOU JOHN FOR THE
INPIRATION AND SUPPORT
DURING ALL THESE YEARS

YES !!! IT IS ONE OF YOUR PICTURES

THE UNIVERSITY OF READING


CENTRE FOR BIOMIMETICS

Wood Matters


A celebration of the work of John R. Barnett