Effect of Sample Geometry on EMC And Moisture Hysteresis of Red Oak (<i>QUERCUS</i> SP.)


  • Rubin Shmulsky
  • Kosasi Kadir
  • Robert Erickson


Wood moisture content, drying hysteresis, drying size effect, drying stress, <i>Quercus</i> sp


Past researchers have shown that equilibrium moisture content (EMC) is influenced by mechanical stress. It has also been widely demonstrated that the size effect in drying produces varying amounts of stress. This experiment related the internal stress developed during drying to the EMC of red oak (Quercus sp.) samples. The results indicated that larger pieces, with larger potential differential stresses, had significantly different EMCs than relatively smaller pieces. The influence of sample size on hysteresis ratio was also examined. The difference between the adsorbing and desorbing EMCs increased with sample size. As sample thickness decreased to 50 μm, the hysteresis ratio reached unity. Thus as internal drying stresses were eliminated from the wood, the hysteresis effect was eliminated. This behavior suggests that differential drying stresses and/or strains are a causal agent for the observed moisture hysteresis in wood.


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