Investigation into the long-term stress relaxation behaviors of white oak (Quercus alba L.) based on the time–temperature–moisture superposition principle

Abstract

ABSTRACT Curving woodworks exhibit wide applications in wooden furniture manufacturing due to the conformable visual and tactile experience, are welcome among consumers. However, the corresponding long-term shape stability facing the stress relaxation is an attention-worthy issue with the fundamental insights about the mesoscopic behaviors of vessels have not been provided. Here, we proposed the investigation into the effect of vessels on stress relaxation behavior of white oak (Quercus alba L.). Results demonstrated that stress relaxation modulus of specimen decreased with the elevation in MC and temperature, and vessel-containing specimens displayed more evident stress relaxation. Providing more physical connotation, Zener model is more suitable for the numerically investigation into the stress relaxation than logarithmic model. The time-temperature-moisture superposition principle (TTMSP) allows us to predict the~10 d and ~1 d stress relaxation behavior of white oak facing different temperatures and MCs. Additionally, stress relaxation of white oak with vessels is more evident, which can be attributed to the stress concentration and resultant deformation around the vessel. We believe that this work is beneficial for obtaining a mesoscopic understanding of vessels on stress relaxation behaviors of wood. It thus paves a way to exploit the methodologies to improve the shape-stability of curving woodworks.