Influence of strain rate, temperature and fatigue on the radial compression behaviour of Norway spruce

Carolina Moilanen*, Tomas Bjorkqvist, Markus Ovaska, Juha Koivisto, Amandine Miksic, Birgitta A. Engberg, Lauri I. Salminen, Pentti Saarenrinne, Mikko Alava

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)

Abstract

A dynamic elastoplastic compression model of Norway spruce for virtual computer optimization of mechanical pulping processes was developed. The empirical wood behaviour was fitted to a Voigt-Kelvin material model, which is based on quasi static compression and high strain rate compression tests (QSCT and HSRT, respectively) of wood at room temperature and at high temperature (80-100 degrees C). The effect of wood fatigue was also included in the model. Wood compression stress-strain curves have an initial linear elastic region, a plateau region and a densification region. The latter was not reached in the HSRT. Earlywood (EW) and latewood (LW) contributions were considered separately. In the radial direction, the wood structure is layered and can well be modelled by serially loaded layers. The EW model was a two part linear model and the LW was modelled by a linear model, both with a strain rate dependent term. The model corresponds well to the measured values and this is the first compression model for EW and LW that is based on experiments under conditions close to those used in mechanical pulping.

Original languageEnglish
Pages (from-to)505-514
Number of pages10
JournalHolzforschung
Volume71
Issue number6
DOIs
Publication statusPublished - Jun 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • radial compression behaviour
  • dynamic modelling of defibration
  • earlywood
  • high strain rate test
  • latewood
  • moist Norway spruce
  • split-Hopkinson pressure bar
  • Voigt-Kelvin material model
  • WET SPRUCE
  • WOOD
  • PRESSURE
  • FIBERS
  • DEGRADATION
  • FREQUENCY
  • REDUCTION
  • MODEL

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