Responsible project leader: Prof. Jouko Halttunen
Duration of the project: 2011 – 2014
Project description:
The project Wood Behavior in Mechanical Pulping is a part of the consortium project Wood Material Fatigue (WoodMat). The consortium project has three members; the responsible persons and institutes being Lauri Salminen, consortium manager, Technical Research Center of Finland (VTT), Professor Mikko Alava, Aalto University and Professor Jouko Halttunen, Tampere University of Technology (TUT). It spans from 1.1.2011 to 31.12.2014.
The consortium project studies wood fatigue physics. The origins of fatigue and how to efficiently generate it in fresh wood are still uncertain and these are the main issue to be solved in the project. The problem is worth solving because fatigue is a significant phenomenon in mechanical pulping, an energy-intense industrial process (annual electrical energy consumption in Finland roughly 10 TWh) and it is commonly accepted that a better fatigue utilization improves the energy efficiency. Our proposed working solution is to identify the changes resulting from controlled fatigue treatments by quantifying the rheological and geometrical changes in the cellular wood structure (methods include ultrasonic evaluation, computer tomography imaging and theoretical considerations).
This part project Wood Behavior in Mechanical Pulping concentrates on wood deformation properties under industrial defibration circumstances i.e. high strain rate loading at high temperatures. This includes compressive loading experiments in an encapsulated split-Hopkinson device in co-operation with Mid-Sweden University, highspeed photography with stress-strain analysis and theoretical analysis of the fundamental behavior of wood.
The consortium combines three competences: experience in the ESS provided by the inventor of the concept (Björkqvist/TUT and Lucander/VTT), wide infrastructure for mechanical pulping research (VTT) and outstanding accomplishments in complex material physics (TKK). The university collaborators strengthen the fundamental physical aspects often overlooked in applied research.
Funding:
Academy of Finland, Tampere University of Technology
Partners:
Technical Research Center of Finland, Aalto University
Personnel:
Research fellow, Dr. Tech. Tomas Björkqvist
Publications:
Björkqvist, T., On the specific energy consumption in mechanical pulping, IMPC 2011. International Mechanical Pulping Conference, Xian, China, June 27 - 29, 2011, Accepted as oral presentation
Salmi, A., Salminen, L., Montonen, R., Engberg, B. A., Björkqvist, T., Hæggström, E., Lucander, M., Cyclic impacting of wood creates localized fatigue, IMPC 2011. International Mechanical Pulping Conference, Xian, China, June 27 - 29, 2011, Accepted as oral presentation