Measurement of internal stress in Radiata pine sapwood during drying using an improved online sensor
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Silvia Ferrari
Abstract
Internal stress in wood as a result of kiln drying is an important factor that affects the quality of the final product. Internal stress is inherently difficult to measure and it is usually either assessed through destructive sample evaluation after drying, or is predictively modelled using extensive material property relations which require much effort to obtain. This study describes improvements of the design, accuracy, and precision of a previously constructed stress sensor for the direct measurement of internal stress in wood during drying. The sensor is designed to be placed directly into a wood block and it records online internal uniaxial stress. Lurethane® was found to be the best material for transmitting internal stress to the sensor because reduced creep was observed, compared with Teflon® which was originally used. Stress modelling showed that a linear relation could be theoretically obtained between the stress from the sensor and the actual primary axis stress that is likely to occur in an intact wood block. Accordingly, the response of a sensor placed in a certain area could be successfully calibrated. However, rotation of the sensor away from the primary stress axis caused a decrease in recorded stress but did not affect stress trends during drying, provided the angle remained constant. Finally, stress results from drying Pinus radiata D. Don at 70°C are also described and discussed.
©2010 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Original papers
- Galactoglucomannan stabilization during the initial kraft cooking of Scots pine
- A CP/MAS 13C-NMR study of cellulose fibril aggregation in eucalyptus dissolving pulps during drying and the correlation between aggregate dimensions and chemical reactivity
- Characteristics and discrimination of five types of wood-plastic composites by FTIR spectroscopy combined with principal component analysis
- Macro- and micromechanical characterization of wood-adhesive bonds exposed to alternating climate conditions
- Viscoelasticity of aspen wood strands during hot pressing: Experimentation and modeling
- Applying digital image correlation to wood strands: Influence of loading rate and specimen thickness
- Influence of loading conditions on the measurement of mode I critical stress intensity factor for wood and medium-density fiberboard by the single-edge-notched tension test
- Advancing the dynamic mechanical analysis of biomass: comparison of tensile-torsion and compressive-torsion wood DMA
- Improvement of water resistance and dimensional stability of wood through titanium dioxide coating
- Analysis of water vapour sorption of oleo-thermal modified wood of Acacia mangium and Endospermum malaccense by a parallel exponential kinetics model and according to the Hailwood-Horrobin model
- Influence of chemical treatments on moisture-induced dimensional change and elastic modulus of earlywood and latewood
- Measurement of internal stress in Radiata pine sapwood during drying using an improved online sensor
- Mechanical potential of eco-OSB produced from durable and nondurable species and natural resins
- Improvement of glued-in-rod joint system using compressed wooden dowel
- Short note
- On the long-term visco-elastic behaviour of polyethylene glycol (PEG) impregnated archaeological oak wood
- Meetings
- Meetings
- Acknowledgement
- Acknowledgement
Articles in the same Issue
- Original papers
- Galactoglucomannan stabilization during the initial kraft cooking of Scots pine
- A CP/MAS 13C-NMR study of cellulose fibril aggregation in eucalyptus dissolving pulps during drying and the correlation between aggregate dimensions and chemical reactivity
- Characteristics and discrimination of five types of wood-plastic composites by FTIR spectroscopy combined with principal component analysis
- Macro- and micromechanical characterization of wood-adhesive bonds exposed to alternating climate conditions
- Viscoelasticity of aspen wood strands during hot pressing: Experimentation and modeling
- Applying digital image correlation to wood strands: Influence of loading rate and specimen thickness
- Influence of loading conditions on the measurement of mode I critical stress intensity factor for wood and medium-density fiberboard by the single-edge-notched tension test
- Advancing the dynamic mechanical analysis of biomass: comparison of tensile-torsion and compressive-torsion wood DMA
- Improvement of water resistance and dimensional stability of wood through titanium dioxide coating
- Analysis of water vapour sorption of oleo-thermal modified wood of Acacia mangium and Endospermum malaccense by a parallel exponential kinetics model and according to the Hailwood-Horrobin model
- Influence of chemical treatments on moisture-induced dimensional change and elastic modulus of earlywood and latewood
- Measurement of internal stress in Radiata pine sapwood during drying using an improved online sensor
- Mechanical potential of eco-OSB produced from durable and nondurable species and natural resins
- Improvement of glued-in-rod joint system using compressed wooden dowel
- Short note
- On the long-term visco-elastic behaviour of polyethylene glycol (PEG) impregnated archaeological oak wood
- Meetings
- Meetings
- Acknowledgement
- Acknowledgement
