Deformation of wet wood under combined shear and compression
2005 (English)In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 39, no 6, 460-471 p.Article in journal (Refereed) Published
During refining of mechanical pulp, a process occurring at high speed at temperatures of 140-160 degrees C, the flexibility and bonding ability of wood fibres are increased. To understand the mechanical behaviour of the fibres in this operation, deformations at low speed of wet wood specimens at 50 degrees C were studied under two different combinations of shear and compression loadings. The results were compared with the behaviour of wet wood in pure compression. Some features of the deformation that occurred in earlywood were analysed using an image analysis procedure. During pure compression the cell walls bend independently of the shape of the fibre cells and their cell wall thickness. Under combined shear and compression, however, mainly the corners of the fibre cells get deformed. In a second deformation performed in compression, the fibre cells follow the same deformation pattern as given by the first deformation type whether in compression or in combined shear and compression. The interpretation was that permanent defects in the cells themselves were introduced already in the first load cycle of the wood samples. The load combination with lower shear gave the same permanent strain as the case of pure compression but using less energy.
Place, publisher, year, edition, pages
2005. Vol. 39, no 6, 460-471 p.
Compaction, Deformation, Image analysis, Mechanical pulp, Natural fibers, Bonding ability, Interpretation, Wet woods
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-6261DOI: 10.1007/s00226-005-0025-xISI: 000232606100005OAI: oai:DiVA.org:kth-6261DiVA: diva2:10928
QC 201010052005-10-142005-10-142010-10-05Bibliographically approved