Failure Modes
from Mechanics of Wood and Wood Composites, J. Bodig & B.A. Jayne, Krieger Publishing, 1993, pp. vii, 5, 291, 297, 299, 305.

Compression

Jeff Thomas, 2010

Failure types of nonbuckling clear wood in compression parallel to grain: (a) crushing, (b) wedge splitting, (c) shearing, (d) splitting, (e) crushing and splitting, (f) brooming or end rolling.

 

 

Tension

Failure types of clear wood in tension parallel to grain: (a) splintering tension, (b) combined tension and shear, (c) shear, (d) brittle tension.

Failure types of clear wood in tension perpendicular to grain: (a) tension failure of earlywood, (b) shearing along a growth ring, (c) tension failure of wood rays.

 

Flexure

Failure types of clear wood in bending with span parallel to grain: (a) simple tension, (b) cross-grain tension, (c) splintering tension, (d) brash tension, (e) compression, (f) horizontal shear.

Failure Models

from Engineering Materials 2, M.F.  Ashby, R.H. Jones, Pergamon Press, 1986, p. 260.

Polymeric foams, showing polyhedral cells.  Some foams have closed cells, others have cells which are open.  Wood cells are similar to closed foam cells.  from Engineering Materials 2: An Introduction to Microstructures, Processing and Design, M.F. Ashby & D.R.H. Jones, Pergamon, 1994, pp. 250, 252-3, 258.

Cell wall bending gives the linear-elastic portion of the stress-strain curve.	When an elastomeric foam is compressed beyond the linear region, the cell walls buckle elastically, giving a long plateau of the stress-strain curve.	When a plastic foam is compressed beyond the linear region, the cell walls bend plastically, giving a long plateau on the stress-strain curve.