Initiation of wood defibration in groundwood pulping, single asperity indentation and scratching

• To understand how the energy requirements of the mechanical pulping process can be reduced, the fundamental mechanisms behind fiber separation in Norway spruce were studied experimentally and analytically. Single tip scratching in heated water was used to reproduce initial defibration mechanisms found industrially. The resulting scratches were then compared with surfaces ground in a real industrial process. Moreover, the mechanical behavior of the wood microstructure was monitored with X-ray computed microtomography as a single hard tip was pressed into it. Subsequent digital image correlation was applied to estimate the strain field in the region around the indenting tip. Regions in the wood with high tensile or shear strains were identified, i.e. where cracking and fiber separation is believed to initiate.

Ämnesord

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Trävetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Wood Science (hsv//eng)

Nyckelord

Defibration

Scratching

Strain analysis

Teknisk fysik med inriktning mot tribomaterial

Engineering Science with specialization in Tribo Materials

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)