An experimental and numerical study of moisture flow and moisture-induced strain in fast-grown Sitka spruce

O'Ceallaigh, Conan, Sikora, Karol, McPolin, Daniel, & Harte, Annette M. (2019). An experimental and numerical study of moisture flow and moisture-induced strain in fast-grown Sitka spruce. Maderas: Ciencia y tecnologia, 21(1), 45-64. doi: 10.4067/S0718-221X2019005000105

Abstract

The use of fast-grown timber in the manufacture of engineered wood products is increasing; however, the fast growth rate results in a low-density timber that is susceptible to significant swelling and shrinkage deformations under changing moisture content. The current study focuses on the characterisation of the moisture diffusion and swelling/shrinkage of fast-grown Sitka spruce and the prediction of the moisture-induced strain development in Sitka spruce glulam beams under variable humidity cycles. Moisture content evolution and swelling/shrinkage coefficients were measured and the longitudinal swelling/shrinkage was found to be significantly greater than for slow-grown timber. Sitka spruce glued-laminated beams were subjected to controlled relative humidity cycling for 52 weeks and the moisture distribution and moisture-induced strains were measured continuously. Coupled moisturedisplacement numerical models, incorporating the experimentally measured material parameters were developed. The effect of the glue-line was found to have an insignificant effect on moisture transport, however, the material orientation greatly influenced the predicted moisture-induced strain. Accurately mapping the material orientation produced significantly better predictions of the experimental results over the 52-week period. Keywords: Adsorption,

Funder

Department of Agriculture, Food and the Marine

Publisher

Departamento de Ingeniería en Maderas de la Universidad del Bio-Bio en Concepción, Chile

Rights

Attribution-NonCommercial-NoDerivs 3.0 Ireland

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Collections

Civil Engineering (Scholarly Articles)