Strain distribution during the heat treatment of wood with digital image correlation, material characterization, and deformation analysis under mechanical stress of heat- treated wood

Abstract

Abstract This paper was to investigate the strain distribution with digital image correlation (DIC) during the heat treatment of Beech and Uludag Fir woods at 170, 190, and 210°C for 4 h and the effects of the heat treatment process on the deformation behavior during mechanical testing of heat-treated wood, and the physical, mechanical, morphological, thermal, chemical properties of the heat-treated woods. According to the mechanical test, the heat treatment parameters can be optimized by using the DIC methods during the treatment, and therefore, it can be said that the DIC method can provide important data in the design of structurally heat-treated wood materials. Although heat treatment can provide improved physical and thermal properties, it caused micro-crack formations and collapses in the wood cells in morphological structure and so, it negatively affected the mechanical properties. FTIR showed that different peaks weren’t detected in the spectra of untreated and heat-treated woods, but it was seen to be slight shifts in the intensity of some peaks of the heat-treated woods. The x-ray diffraction results showed a slight difference in the XRD patterns of the heat-treated woods and while the thermal treatment was raised, the crystallinity generally increased more.