Published Date
Abstract
The theory that is thought to best explain the recovery of collapse reconditioning supposes that the S1 and S3 layers are largely responsible for providing restoring the cells to the un-collapsed shape. This is because these two layers are particularly important in providing circumferential stiffness to each individual cell lumen. Hence, it is the potential energy stored in these layers that principally provides the force to restore the cell shape. In contrast, the S2 layer is considered to be the most important for providing the inelastic material properties required to hold the cell in the collapsed or deformed state. While moisture content is important for its effect on the cell wall material properties (i.e. stiffness, creep, mechano-sorptive creep), the uptake or movement of moisture within the cell walls is not thought to be critical for collapse recovery. In this sense, the recovery phenomenon can largely be attributed to a thermal effect (Blakemore and Langrish, 2008), and hence it is the relationships with temperature for the various material properties which are critical for this modelling work. The effect of heat then is to soften the S2layer, which is holding the cell in the deformed shape, allowing the stored mechanical energy in the S1 and S3layers to restore the cell shape.
References
For further details log on website :
http://link.springer.com/chapter/10.1007/978-90-481-9550-3_5
Date:
Title
A Theoretical Model of Collapse Recovery
- Author
- Philip Blakemore
Abstract
The theory that is thought to best explain the recovery of collapse reconditioning supposes that the S1 and S3 layers are largely responsible for providing restoring the cells to the un-collapsed shape. This is because these two layers are particularly important in providing circumferential stiffness to each individual cell lumen. Hence, it is the potential energy stored in these layers that principally provides the force to restore the cell shape. In contrast, the S2 layer is considered to be the most important for providing the inelastic material properties required to hold the cell in the collapsed or deformed state. While moisture content is important for its effect on the cell wall material properties (i.e. stiffness, creep, mechano-sorptive creep), the uptake or movement of moisture within the cell walls is not thought to be critical for collapse recovery. In this sense, the recovery phenomenon can largely be attributed to a thermal effect (Blakemore and Langrish, 2008), and hence it is the relationships with temperature for the various material properties which are critical for this modelling work. The effect of heat then is to soften the S2layer, which is holding the cell in the deformed shape, allowing the stored mechanical energy in the S1 and S3layers to restore the cell shape.
References
- Astley RJ, Stol KA, Harrington JJ (1998) Modelling the elastic properties of softwood. Part II: The cellular microstructure. Holz Roh Werkst 56:43–50CrossRef
- Blakemore P (2008) Optimisation of steam reconditioning for regrowth-ash and plantation grown eucalypt species.PhD Thesis, The University of Sydney. 327 pp. http://hdl.handle.net/2123/2343. Accessed 3 August 2010
- Blakemore PA, Langrish TAG (2008) Effect of pre-drying schedule ramping on collapse recovery and internal checking with Victorian Ash eucalypts. Wood Sci Technol 42(6):473–492CrossRef
- Chafe SC, Barnacle JE, Hunter AJ, Ilic J, Northway RL, Rozsa AN (1992) Collapse: an introduction. CSIRO Division of Forest Products, Melbourne, 9 pp
- Harrington JJ, Booker R, Astley RJ (1998) Modelling the elastic properties of softwood. Part 1: The cell wall lamellae. Holz Roh Werkst. 56:37–41
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For further details log on website :
http://link.springer.com/chapter/10.1007/978-90-481-9550-3_5
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