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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.

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Presentation on theme: "THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett REACTION WOODS INSPIRATION FOR SMART MATERIALS."— Presentation transcript:

1 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

2 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

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

4 Wood microstructure 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

5 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

6 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

7 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

8 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

9 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

10 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 WoodPoplar – Tension Wood

11 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

12 THE UNIVERSITY OF READING CENTRE FOR BIOMIMETICS Wood Matters – A celebration of the work of John R. Barnett Tension or Compression Wood Cell element

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

14 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

15 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

16 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

17 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


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