Modeling and experimental validation of elastic modulus of Pinus yunnanensis exposed to high relative humidity

Wood as a renewable engineering material has widely been used for structural purpose for decades, but its static bending modulus of elasticity (Eb) has not been seriously researched in large-scale relative humidity fluctuant environment. This paper presents an experimental and numerical study for the assessment of Eb of Pinus yunnanensis as a function of moisture content and its distribution in high relative humidity environment. For this, a moisture transfer model based on a multi-phase-type approach and a classical theory of laminated plate was used. The experimental results indicated that the predicted Eb had good agreement with measured data making it possible for researchers, designers, and industry in the field of wood mechanics and products to directly obtain the wood Eb by way of calculation. Furthermore, it was also found that there was a decrease in Eb in the short term when the environment relative humidity increased substantially. This phenomenon reminds designers and industry in the field of wood mechanics and products that using so-called Eb with equilibrium moisture content as the actual mechanical value of structural-use wood may bear a potential risk.