摘要
Time-temperature superposition principle (TTSP) was used to examine dynamic viscoelastic properties of Chinese Fir(Cunninghamia lanceolata) wood at an extremely low moisture content(0.6%).Storage modulus and loss factor data were obtained at different constant temperatures ranging from 25℃to 150℃in frequency multiplexing experiments(0.1 -20 Hz).All viscoelastic curves at other temperatures were shifted along the log-frequency axis to superimpose them on a reference temperature(i.e.135℃in this study) curve.The extended storage modulus and loss factor isothermal master curves were over a wide range of frequency.The shift factors were determined to be a function of temperature and fitted into the Arrhenius equation with the least squares method.The results showed that the storage modulus data were excellently fitted into the Arrhenius model,indicating the validity of the model to characterize the dynamic stiffness behavior of dry wood in the range of 25-150℃using the TTSP. However,the time-temperature equivalence was not able to predict the damping properties.
Time-temperature superposition principle (TTSP) was used to examine dynamic viscoelastic properties of Chinese Fir(Cunninghamia lanceolata) wood at an extremely low moisture content(0.6%).Storage modulus and loss factor data were obtained at different constant temperatures ranging from 25℃to 150℃in frequency multiplexing experiments(0.1 -20 Hz).All viscoelastic curves at other temperatures were shifted along the log-frequency axis to superimpose them on a reference temperature(i.e.135℃in this study) curve.The extended storage modulus and loss factor isothermal master curves were over a wide range of frequency.The shift factors were determined to be a function of temperature and fitted into the Arrhenius equation with the least squares method.The results showed that the storage modulus data were excellently fitted into the Arrhenius model,indicating the validity of the model to characterize the dynamic stiffness behavior of dry wood in the range of 25-150℃using the TTSP. However,the time-temperature equivalence was not able to predict the damping properties.
