This paper introduces, with the development of user-subroutines in the finite-element software Abaqus FEA®, a new practical analysis tool to simulate transient nonlinear moisture transport in wood. The tool is used to revisit the calibration of moisture simulations prior to the simulation of mechanical behaviour in bending subjected to climate change. Often, this calibration does not receive sufficient attention, since the properties and mechanical behaviour are strongly moisture dependent. The calibration of the moisture transport simulation is made with the average volumetric mass data experimentally obtained on a paired specimen of Norway spruce (Picea abies) with the dimensions 30×15×640mm3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$30\times 15\times 640\, {\mathrm{mm}}^{3}$$\end{document}. The data, from a 90-day period, were measured under a constant temperature of 60 °C and systematic relative humidity cycles between 40 and 80%. A practical method based on analytical expressions was used to incorporate hysteresis and scanning behaviour at the boundary surface. The simulation tool makes the single-Fickian model and Neumann boundary condition readily available and the simulations more flexible to different uses. It also allows for a smoother description of inhomogeneity of material. The analysis from the calibration showed that scanning curves associated with hysteresis cannot be neglected in the simulation. The nonlinearity of the analysis indicated that a coherent set of moisture dependent diffusion and surface emission coefficient is necessary for the correct description of moisture gradients and mass transport.

中文翻译：

---

木材三维正交各向异性非线性瞬态水分模拟：分析扫描曲线和非线性的影响

随着有限元软件 Abaqus FEA® 中用户子程序的开发，本文介绍了一种新的实用分析工具，用于模拟木材中的瞬态非线性水分传输。该工具用于在模拟受气候变化影响的弯曲机械行为之前重新审视水分模拟的校准。通常，这种校准没有得到足够的重视，因为特性和机械性能与湿度有很大关系。水分输送模拟的校准是使用在尺寸为 30×15×640mm3\documentclass[12pt]{minimal}\usepackage{amsmath}\ 的挪威云杉（Picea abies）配对标本上实验获得的平均体积质量数据进行的。 usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$30\times 15\次 640\，{\mathrm{mm}}^{3}$$\end{document}。90 天的数据是在 60 °C 的恒温和 40% 到 80% 的系统相对湿度循环下测量的。使用基于解析表达式的实用方法来结合边界表面的滞后和扫描行为。该仿真工具使单 Fickian 模型和 Neumann 边界条件易于使用，并且仿真对于不同用途更加灵活。它还允许更平滑地描述材料的不均匀性。校准分析表明，在模拟中不能忽略与滞后相关的扫描曲线。分析的非线性表明，要正确描述水分梯度和质量传输，需要一组连贯的水分相关扩散和表面发射系数。