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RESUMENSe determinó la variación del contenido de humedad de equilibrio (CHE) en el tiempo, en especies con diferente densidad básica (Db). Además, se generó un modelo para la predicción del CHE en función de los factores ambientales y algunas propiedades físicas de la madera.Probetas de 2.5 x 7.5 x 20 cm, en espesor, ancho y largo, respectivamente, provenientes de 3 coníferas y 6 latifoliadas, fueron ubicadas en un cobertizo al exterior, y se controló el peso (Pa) de ellas, así como también, la temperatura (T) y la humedad relativa(HR) del aire, una vez por semana y por dos años. Finalizado el ensayo, se determinó la densidad básica (Db), densidad anhidra (Da), peso específico de la pared celular anhidra (Gbpc) y la porosidad anhidra (V), de las probetas.La variación del CHE de la madera en el tiempo, fue mayor en especies de menor Db y mayor V. El modelo que consideró la T, HR, Gbpc y Pa, como variables independientes, explicó en un 98,5% la variación del CHE. El coeficiente de correlación (R) entre valores del CHE medidos y del CHE estimados por el modelo, fue 0.979.Palabras clave: Contenido de humedad de equilibrio, densidad de la madera, porosidad, peso específico de la pared celular, regresiones múltiples. ABSTRACTThe equilibrium moisture content (EMC) variation owing to the time in species with different basic density (BD) was determined. Further, of generating a model for the prediction of EMC as a function of environmental factors and some physical properties of wood.Small samples of 2.5 x 7.5 x 20 cm in depth, width and length, respectively, from 3 conifers and 6 hardwoods were located in a shed at the exterior. And the weight of small samples (WSS), as well as, the temperature (T) and relative humidity (RH) of air were controlled, once a week and for 2 years. After finishing the trial the basic density (BD), oven dry density (ODD), specific gravity of the cell wall (SGCW) and porosity (P) of the small samples were determined.

The objective of this work was to simulate the stresses produced during the drying of Eucalyptus nitens wood due to variations in the moisture content. The methodology involved experimental determination and simulation of drying stresses caused by the development of internal moisture content gradients. Modeling of the moisture transport was based on the concept of an effective diffusion coefficient. The mathematical model for stress-strain, and for moisture diffusion into the wood, was constituted by a system of second-order nonlinear partial differential equations with variable coefficients, which were numerically integrated by the control volume based on the finite element method (CVFEM). For validation purposes, tests were realized for evaluating deformations, stress drying, and moisture gradients that were produced during the drying of Eucalyptus nitens. The results showed satisfactory agreement between the experimental and simulated values, indicating an effective simulation.

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