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In this work, a two-dimensional mathematical model of the moisture transport and stress–strain phenomena during the conventional drying process of Eucalyptus nitens wood is presented. The model consists of a system of partial differential nonlinear second-order equations, where the moisture transport phenomenon is modeled on the concept of effectiv...
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... numerical integration of this differential mathematical model was performed through the finite element control volume method (CVFEM); for more details see Salinas et al. (2011b). The physical and mechanical parameters of the model that were determined according to the previous discussion are given in Table 1, where the constants used in Eq. (3) to determine the effective diffusion coefficients are presented. In addition, the averages of effective coefficient diffusion for the radial and tangential directions are indicated. ...Similar publications
An investigation was carried out to examine the potential to use modified wood as a replacement for metallic connections in timber structures. In recent years, there have been several studies examining the potential to utilise modified wood to improve the performance of engineered wood products. This study describes the development of finite elemen...
Citations
... The mechanical hygroscopic strain and delayed elastic strain were considered in this model [48]. Salinas et al. tested and simulated the drying stress of Pinus radiata D. Don, and obtained the solutions by combining the method of volume control and finite element [53,54]. Then, a two-dimensional mathematical model of stress in the conventional drying process of eucalyptus was established based on the assumption of viscoelastic deformation [54]. ...
... Salinas et al. tested and simulated the drying stress of Pinus radiata D. Don, and obtained the solutions by combining the method of volume control and finite element [53,54]. Then, a two-dimensional mathematical model of stress in the conventional drying process of eucalyptus was established based on the assumption of viscoelastic deformation [54]. ...
Wood drying stress causes various drying defects, which result from the wood microstructure and the transfer of heat and mass during the drying. It is the fundamental way to solve the problem of defects to clarify the law and mechanism of wood stress and strain development during drying. In this paper, based on the defects of wood drying, the theory and experimental testing methods of drying stress and strain were summarized. Meanwhile, artificial neural networks (ANN) and their application in the wood drying field were also investigated. The traditional prong and slicing methods were used practically in the research and industry of wood drying, but the stress changes in-process cannot be trapped. The technologies of image analysis and near-infrared spectroscopy provide a new opportunity for the detection of drying stress and strain. Hence, future interest should be attached to the combination of the theory of heat and mass transfer and their coupling during drying with the theory of microscopic cell wall mechanics and macroscopic drying. A more complete image acquisition and analysis system should be developed to realize the real-time monitoring of drying strain and cracking, practically. A more feasible and reasonable prediction model of wood drying stress and strain should be established to achieve the accuracy of the prediction.
... Some researchers (Gerhards and Link 1987;Barrett and Foschi 1987;Fridley et al. 1992) laid the foundation for the study of wood cumulative damage model and creep model, followed by a series of studies on wood creep (Hanhijärvi 1995(Hanhijärvi , 2000aPavel et al. 2015;Qin and Yang 2018;Huang 2016;Huc 2019). With the enrichment of the test data, scholars further studied the effects of different sizes and temperatures on creep (Peng et al. 2017;Chang and Lam 2018;Hsieh and Chang 2018;Chiniforush et al. 2019), moisture-induced stress (Frandsen 2007;Fortino et al. 2009;Angst-Nicollier 2012;Angst-Nicollier and Malo 2013;Salinas et al. 2020), and constitutive models (Hassani et al. 2015). The effects of creep induced by both load and humidity on the long-term performance of wood members have also been analyzed (Massaro and Malo 2019). ...
... In recent years, based on Hanhijärvi's studies, two-dimensional and three-dimensional moisture induced stress models and orthotropic constitutive models considering mechanical adsorption have been studied (Frandsen 2007;Hassani et al. 2015;Salinas et al. 2020). Fortino et al. (2009) developed a 3D orthotropic-viscoelastic-mechanosorptive model for wood, and it was further developed by many other authors later and currently. ...
Wood is an indispensable building material for modern structures. As a kind of biological material, it is more likely than other materials to be affected by the environment. It has been shown that the effect of long-term exposure to humidity will accelerate the decrease in mechanical properties and long-term strength of wood and wood-based products. The most commonly used methods for studying the deterioration of the mechanical properties of wood and wood-based products under the action of long-term humidity exposure are artificially accelerated aging and outdoor exposure. Many scholars have studied various artificially accelerated aging tests, which can accelerate the aging of wood and wood-based products and save substantial time. However, the results of outdoor exposure tests can be better correlated with the aging of the materials in the actual environment. Scholars have established a relationship between artificially accelerated aging tests and the results of outdoor exposure tests and have studied the results of outdoor exposure tests under different climatic conditions. This paper not only reviews the artificially accelerated aging tests used for wood and wood-based products in the past twenty years, but also summarizes their characteristics and application scope. In addition, the relationship between the outdoor exposure tests and the artificially accelerated aging tests is reviewed. At the end of the paper, the challenges and prospects for the future works are put forward.
... Despite the potential of Eucalyptus nitens timber to be used as a structural element, its application in Chile is still incipient. On the one hand, the tensions induced by the tree growth processes and the subsequent drying process of the sawn timber affect the quality of its mechanical properties [5,6]. On the other hand, since Chilean Eucalyptus nitens forests are mainly managed for the pulp and paper industry, tree pruning or thinning processes are not usual, since the aim is to saw the wood in short rotation periods. ...
... Firstly, the recommendation of [44] was followed to approximate some elastic properties of hardwoods as a proportion of Exdt ( 0.14 , 0.08 , 0.10 , 0.032 , 0.07 ). Secondly, a constant value of 0.35 was assumed for the three Poisson coefficients, as indicated in other investigations [4,5]. Finally, the local variation of Exdt was implemented by dividing the wood boards into 12 segments each of them with a length of 200 mm. ...
Eucalyptus nitens is a fast-growing wood species with a relevant presence in countries like Australia and Chile. The sustainable construction goals have driven the search of structural applications for Eucalyptus nitens; however, this process has been complicated due to the defects usually presented in these timber boards. This study aims to evaluate the dynamic elasticity modulus (Exd) of Eucalyptus nitens timber boards through non-destructive vibration-based tests. Thirty-six timber boards with different levels of knots and cracks were instrumented and tested in a simply supported condition by measuring longitudinal and transverse vibrations. In the first stage, the Exd was calculated globally through simplified normative formulas. Then, in a second stage, the local variability of the Exd was estimated using operational modal analysis (OMA), finite element numerical simulations (FEM), and regional sensitivity analysis (RSA). The positive correlation found between the global static modulus of elasticity and Exd suggests that non-destructive techniques could be used as a reliable and fast alternative for the assessment of bending stiffness. Finally, the proposed method to estimate the local variability of Exdt based on the combination of OMA, FEM, and RSA techniques was useful to improve the structural selection process of timber boards for lightweight social housing floors.
The growth process of eucalyptus plants in the form of log volume is influenced by abiotic, and biotic factors, which then have a relationship with climate, genotype, soil conditions, both physical, and chemical, silvicultural practices, and forest management. Therefore, to improve forest resilience, and productivity, identification of eucalyptus plants is needed. The most promising tool available to help government, and companies is to use eucalyptus-based models. This model is useful for getting the right planning, assessing the variables that affect climate, and determining long-term direction, and for seeing changes in the forest sector. Individual growth models with trees, and st, anding levels are needed to estimate future forest structures. The purpose of this study is to provide information about the models, and simulations used in the process of replanting eucalyptus plants that have benefits in various sectors of life.
