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Wood structure
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Softwood: Cedar
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Hardwood: Oak
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Wood Structure
Modified; after Fig. 5.14 in Dinwoodie © Van Nostrand Reinhold. All ri ghts reserved. This content i s excludedfrom our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
Stress strain curves
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Balsa
Figure removed due to co pyright re strictions. See Figure 3: Easterling, K. E., R. Harrysson, et al . "On the
Mechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Balsa: Tangential
Figure removed due to co pyright re strictions. See Figure 4: Easterling, K. E., R. Harrysson, et al . "On theMechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Figure removed due to co pyright re strictions. See Figure 7: Easterling, K. E., R. Harrysson, et al . "On the
Mechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Balsa: Radial
Figure removed due to co pyright re strictions. See Figure 5: Easterling, K. E., R. Harrysson, et al . "On the
Mechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Balsa: Axial
Figure removed due to co pyright re strictions. See Figure 6: Easterling, K. E., R. Harrysson, et al . "On theMechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Douglas Fir: Tangential Comp
Figure removed due to copyright restrictions. See Bodig, J., and B. A. Jayne.
Mechanics of Wood and Wood Composites. Van Nostrand Reinhold, 1982.
Douglas fir: Radial comp.
Figure removed due to co pyright re strictions. See Bodig, J., and B. A. Jayne.
Mechanics of Wood and Wood Composites. Van Nostrand Reinhold, 1982.
Norway spruce: Axial comp
Images removed due to copyright restrictions. See Figure 5.14: Dinwoodie,J. M. Timber: Its Nature and Behaviour. Van Nostrand Reinhold, 1981.
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Model for wood microstructure
Figure removed due to copyright restrictions. See Figure 2: Easterling, K. E., R. Harrysson, et al. "On the
Mechanics of Balsa and Other Woods." Proceedings The Royal of Society. A 383, no. 1784 (1982): 31-41.
Gibson, L. J., and M. F. Ashby. Cellular Solids: Structure and Properties. 2nd ed. Cambridge
University Press, © 1997. Figure courtesy of Lorna Gibson and Cambridge University Press.
Wood: Honeycomb Models
Gibson, L. J., and M. F. Ashby. Cellular Materials in Nature and Medicine. 2nd ed. Cambridge
University Press, © 2010. Figure courtesy of Lorna Gibson and Cambridge University Press.
Wood: Honeycomb Models
YO
UN
G’S
MO
DU
LUS,
E (
GPa
)
1000
100
10
10
1.0
1.0 3.0
0.1
0.1 0.30.01
0.03
balsa
balsa
spruce
spruce
oak
oak
teak
slope 1
slope 3
teak
pine
pine(LD)
(LD)
(MD)
(MD)
(HD)
(HD)
woods,parallelto grain
woods,perpendicular
to grain
celluloseE = 120-140 GPa
Modulus - Densityfor woods
(HD), (MD), (LD) = High/Medium/Low Density
DENSITY, (Mg/m3)(a)
hemicelluloseE = 5-8 GPa
solid composites ofcellulose, lignin and
hemicellulose liein this envelope
ligninE = 2.5-3.7 GPa
woodcell wall
Diagram removed due to copyright restrictions. See Figure 5b: Gibson, L. J. "The Hierarchical Structureand Mechanics of Plant Materials." Journal of the Royal Society Interface 9 (2012): 2749-66.
Wood in Bending: E1/2/ρ (E* ) (Es ) " ρ
* = s %$ * 'ρ ρ ρ
1/2 1/2
s # &
1/2
Stiffness performance index for wood in bending is similar to that for best engineering composites
Modified from Ashby (1992) © Butterworth Heinemann. All rights reserved. This content is excluded
from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
Wood in Bending: σ 2/3f /ρ
σ f*( )2 /3ρ*
=σ ys( )2 /3ρs
ρsρ*
#
$%&
'(
1/3
Strength performance index for wood in bending is similar to that for best engng composites
Modified from Ashby (1992) © Butterworth Heinemann. All rights reserved. This content is excluded
from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.
Figure removed due to copyright restrictions. See The internationalbook of wood. Bramwell, M, ed. Artists House, 1982. pp 186-87.
Engineered Wood Products: A Guide for Specifiers, Designers and Users, S. Smulski Ed. PFS Research Foundation, 1997
Image of graceful glued-laminated timber arch bridge removed due to copyright
restrictions. See Figure 13: Engineered Wood Products: A Guide for Specifiers,
Designers and Users. Smulski, S., ed. PFS Research Foundation, 1997.
MIT OpenCourseWarehttp://ocw.mit.edu
3.054 / 3.36 Cellular Solids: Structure, Properties and ApplicationsSpring 2015
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