Strength Degradation of Wood Members Based on the Correlation of Natural and Accelerated Decay Experiments
Strength Degradation of Wood Members Based on the Correlation of Natural and Accelerated Decay Experiments
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DOI：
10.32604/jrm.2020.09020
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发表时间：
2020
影响因子：
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通讯作者：
Xueliang Wang;Qiangang Xu;X. Wang;Junhui Guo;Wancheng Cao;Chun Xiao
中科院分区：
文献类型：
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作者：
Xueliang Wang;Qiangang Xu;X. Wang;Junhui Guo;Wancheng Cao;Chun Xiao
同时进行加速衰减试验和自然衰减试验，探讨长期暴露于自然环境下腐朽木构件的强度退化情况。进行自然衰减试验，测定木材构件的抗弯强度、平行纹抗压强度和弹性模量，6组试件分别在自然环境中衰减3 ~ 18个月。与相应的衰变试验进行比较，其中在加速条件下测量了另外6组试件。收集的实验数据用Pearson积差进行相关性评估。结果表明，加速衰减的力学性能与自然环境下的力学性能高度相关，两者均呈相同的下降趋势。在给定的试验条件下，对加速衰减试验数据均值进行曲线拟合，得到抗弯强度、平行粒抗压强度、弹性模量随时间变化的退化模型。基于高相关性，推导了两种试验的加速度位移因子（ASF），其中抗弯强度为2.934，抗压强度为2.519，弹性模量为2.346，建立了长期自然环境下的强度退化模型。结果表明，指数函数1 / 4 0e t能够准确地反映自然环境下木材构件力学性能的退化情况。
An accelerated decay test and a natural decay test were conducted synchronically to explore the strength degradation of decaying wood members under long-term exposure to natural environment. A natural decay test was carried out to measure the bending strength, compressive strength parallel to grain and modulus of elasticity of the wood members, with 6 groups of specimens decayed in natural environment for 3 to 18 months respectively. To compare with corresponding decay test, in which 6 other groups of specimens were measured under accelerated conditions. The experimental data collected were evaluated by Pearson productmoment for the correlation. The results indicate that the mechanical properties of the accelerated decay were highly correlated with those in natural environment, both of which decreased in the same trend. Under the given test conditions, the mean value of the accelerated decay test data were curve-fitted to achieve the time-dependent degradation model of the bending strength, the compressive strength parallel to grain, as well as the modulus of elasticity. Due to the high correlation, the acceleration shift factors (ASF) of the two tests were derived, where the bending strength of 2.934, the compressive strength parallel to grain of 2.519 and the elastic modulus of 2.346 were employed to formulate the strength degradation models in the long-term natural environment. The results verify that the exponential function 1⁄4 0e t enables to exactly capture the degradation of the mechanical properties of wood members decayed in natural environment.