TUTCRIS

TY - JOUR

T1 - Influence of strain rate, temperature and fatigue on the radial compression behaviour of Norway spruce

AU - Moilanen, Carolina

AU - Björkqvist, Tomas

AU - Ovaska, Markus

AU - Koivisto, Juha

AU - Miksic, Amandine

AU - Engberg, Birgitta A.

AU - Salminen, Lauri I.

AU - Saarenrinne, Pentti

AU - Alava, Mikko

PY - 2017/6/27

Y1 - 2017/6/27

N2 - 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°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.

AB - 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°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.

KW - dynamic modelling of defibration

KW - earlywood

KW - high strain rate test

KW - latewood

KW - moist Norway spruce

KW - radial compression behaviour

KW - split-Hopkinson pressure bar

KW - Voigt-Kelvin material model

U2 - 10.1515/hf-2016-0144

DO - 10.1515/hf-2016-0144

M3 - Article

VL - 71

SP - 505

EP - 514

JO - Holzforschung

JF - Holzforschung

SN - 0018-3830

IS - 6

ER -