基于X射线计算机断层扫描技术的重组竹湿热耦合老化评估

Hydrothermal aging evaluation method of recombinant bamboo based on X-ray computed tomography technology

  • 摘要: 为了预测重组竹制品在实际使用中的寿命,基于X射线计算机断层扫描技术(X-ray computed tomography technology,X-CT),采用标准BS EN 1087-1:1995作为重组竹湿热耦合老化条件,以其CT值和老化分析指标的数学模型评估重组竹湿热耦合老化后结构强度的损失。结果表明:重组竹老化后密度、内胶合强度和CT值均小于老化前,且老化前后差异显著。随老化时间增加,其密度、内胶合强度和CT值的损失均增加,且变化趋势基本一致,在1~2 h阶段变化较大,在2.5~4.5 h阶段变化较平缓,在老化4.5 h时达到峰值;将CT值差值与密度差值拟合为线性模型,模型相关系数R2=0.9270,验证模型R2=0.9438。CT值差值与内胶合强度差值拟合为Allometric模型,模型相关系数R2=0.9488,验证模型R2=0.9439;竹材自身的植物学特征及重组竹压制工艺造成了试验数据离散及老化前后离散程度发生改变。可通过改善重组竹制备工艺提高其内部均匀性及降低老化前后离散程度变化,以提高模型预测精度。

     

    Abstract: To predict their lifespan of reconstituted bamboo products in practical use, X-ray computed tomography technology (X-CT) was employed and the standard of BS EN 1087-1:1995 was used as the hydrothermal aging condition of recombinant bamboo. The loss of structural strength was evaluated by the mathematical model of the CT value and the aging analysis indicators after hydrothermal aging of reconstituted bamboo. The results show that:the density, the internal bond strength and the CT value of recombinant bamboo are decreased after aging than before aging, and the differences are significant before and after aging. With the increasing of the aging time, the losses of the density, the internal bond strength and the CT value are increased and their changing trends are basically the same, which rapidly change in 1-2 h and gently change in 2.5-4.5 h and reach the peak at 4.5 h; the CT value difference and the density difference are fitted into linear model whose model correlation coefficient R2 and validation model R2 are 0.9270 and 0.9438, respectively, and the CT value difference and the internal bond strength difference are fitted into Allometric model whose model correlation coefficient R2 and validation model R2 are 0.9488 and 0.9439, respectively; the botanical characteristics of bamboo and the press technology of reconstituted bamboo cause the discretizing of the experimental data and the change of the discretizing before and after aging. The internal uniformity of reconstituted bamboo can be improved and the change of the discretizing before and after aging can be reduced by improving the press technology to enhance the prediction accuracy of the models.

     

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