Modelling and simulation of radial spruce compression to optimize energy efficiency in mechanical pulping

Carolina Moilanen, Tomas Björkqvist, Markus Ovaska, Juha Koivisto, Amandine Miksic, Birgitta Engberg, Lauri Salminen, Pentti Saarenrinne, Mikko Alava

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


Energy efficiency of mechanical pulping is rather low. One possibility to facilitate design of more energy efficient defibration is to model and simulate wood compression. This paper presents an effort to model the behavior of Norwegian spruce in radial compression at defibration circumstances. To identify strain rate dependent properties, compression tests were conducted at both quasi-static conditions and at high strain rate. All tests were done at relevant moisture content and up to defibration zone temperatures and strain rates. Additionally the tests were performed both on native wood and on pre-fatigued wood to include behavior dependency of fatigue. The compression tests were monitored on fiber level to separately model behavior of early- and latewood. The chosen continuum model structure for earlywood and latewood was Voight-Kelvin to enable explicit viscous behavior conditioned by strain rate in parallel to the elastic behavior. The presented model is the first wood compression behavior model individually for earlywood and latewood that is based on wood experiments at industrial defibration circumstances. The influences of temperature and pre-fatigue rise are both softening as expected, The utilization of the compression model was demonstrated in an initial multilayered wood compression simulation.

Original languageEnglish
Title of host publicationInternational Mechanical Pulping Conference 2016, IMPC 2016
PublisherTAPPI Press
Number of pages18
ISBN (Electronic)9781510830738
Publication statusPublished - 2016
MoE publication typeA4 Conference publication
EventInternational Mechanical Pulping Conference - Jacksonville, United States
Duration: 26 Sept 201628 Sept 2016


ConferenceInternational Mechanical Pulping Conference
Abbreviated titleIMPC
Country/TerritoryUnited States


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