INSPIRATION FOR SMART MATERIALS 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

WHAT IS INTERESTING ABOUT REACTION WOODS ? 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

THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Adaptive shape change Why aren’t all trees the shape of weeping willows ? Reaction wood is used by trees to modulate shape of trunk and branches

THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Fibres provide the key organisational elements for functional self-assembly 20-30 mm Wood microstructure

Wood Matters – A celebration of the work of John R. Barnett 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 Cave, 1980 Barnett & Jeronimidis, 2003 Clair, 2001

Wood Matters – A celebration of the work of John R. Barnett 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 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 Hygro- or thermal expansivity of angle-ply structures

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 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

De-hydration / Maturation 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 normal wood tension wood Non-symmetric laminate Shape change (curvature) De-hydration / Maturation Poplar – Normal Wood Poplar – Tension Wood Coutand et al, 2004

THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Inspiration for engineering solutions Adaptive roof element

Tension or Compression Wood “Cell” 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

“Tissue / Organ” element THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Tension wood side “Tissue / Organ” element

Element combining “tension” and “compression” wood THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Compression wood side Tension wood side Element combining “tension” and “compression” wood

THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Stretching-Bending Different materials Different scale Different actuation …………………………….but SAME FUNCTIONALITY

DIFFERENTIATION AT THE “STRUCTURE” LEVEL THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Conclusions DIFFERENTIATION AT THE “MATERIAL” LEVEL (Anisotropy, Heterogeneity, Hierarchies) + DIFFERENTIATION AT THE “STRUCTURE” LEVEL (Shape, Dimensions, Geometry) FUNCTIONAL INTEGRATION AT THE “SYSTEM” LEVEL

THANK YOU JOHN FOR THE INPIRATION AND SUPPORT DURING ALL THESE YEARS THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett THANK YOU JOHN FOR THE INPIRATION AND SUPPORT DURING ALL THESE YEARS YES !!! IT IS ONE OF YOUR PICTURES