木材乾燥に適応可能な新規レオロジーモデルの開発

在测定杉木和桧木箱心木材的表面和内层的粘弹性蠕变性质之后，然后使用悬臂蠕变试验在20、65、80和90°C的温度下进行木材的表面和内层的机械吸附蠕变性质的测定。在20 ° C和65°C的温度下，施加其断裂载荷的20%的载荷用于蠕变试验。在80 ° C和95°C的温度下进行蠕变试验的情况下，在悬臂的自由端施加其断裂载荷的10%的载荷。应变片在第四跨度处粘结在试样的上表面和下表面上。在恒温恒湿箱中，对承受载荷和相对湿度（RH）循环变化36 h的试件进行挠度和应变测量。将机械吸附蠕变定义为累积含水率变化的函数，并采用由一个Kelvin单元和一个阻尼器串联组成的模型来确定木材的机械吸附蠕变特性。从蠕变试验结果来看，温度对木材的蠕变性能有显著的影响。木材表层和内层试样的蠕变柔量随温度的升高而增大。此外，在第一次RH循环时观察到试样的最大挠度和蠕变速率。用本研究中所用的模型对实验数据进行拟合，结果吻合较好。因此，本研究所获得的模型参数适用于木材的机械吸附蠕变性能的识别。

Following determination of viscoelastic creep properties of surface and inner layer of Sugi and Hinoki boxed-heart timber, determination of mechano-sorptive creep properties of surface and inner layer of the timbers was then conducted at temperature of 20, 65, 80 and 90°C using cantilever creep test. A load of 20% from its rupture load was applied for the creep test at temperature of 20 and 65°C. In case of the creep test at temperature of 80 and 95°C, a load of 10% from its rupture load was applied at the free-end of the cantilever. Strain gauges was bonded at a fourth span on upper and bottom faces of the specimen. Deflection and strain were measured on the specimen subjected to load and cycling change of relative humidity (RH) in a temperature and humidity chamber for 36 h. Mechano-sorptive creep is defined as a function of cumulative moisture content change and a model consisted of one Kelvin unit and one dashpot connected in a series was used to determined mechano-sorptive creep properties of the timber. From the creep test results, it was found that temperature had significant effects on the creep properties of the timber. The creep compliance of surface and inner layer specimen of the timbers tended to increase as temperature increased. In addition, the largest deflection and creep rate of the specimen was observed at the first RH cycle. Fitting experimental data with model used in this research shows a good agreement. Therefore, model parameters obtained in this research were applicable for identification of mechano-sorptive creep properties of the timber.