Lomnitz-type viscoelastic behavior of clear spruce wood as identified by creep and relaxation experiments: influence of moisture content and elevated temperatures up to 80 °C

Abstract

The strong dependence of viscoelastic behavior of wood on temperature and moisture content is well documented in the literature. In this paper, viscoelastic behavior of spruce wood is monitored experimentally and modeled with a (logarithmic) Lomnitz-type creep model. Creep tests are performed at different levels of temperature (25-80∘C) and moisture content (0 to ≈ 15 mass-%). The variation of Lomnitz parameters as regards temperature and moisture content is well captured by Arrhenius-type dependencies. Furthermore, the uniqueness of the results is discussed and relaxation tests are performed in order to verify the so-obtained viscoelastic parameters.