Mechanical behavior of walnut (Juglans regia L.) and cherry (Prunus avium L.) wood in tension and compression in all anatomical directions. Revisiting the tensile/compressive stiffness ratios of wood

Abstract

Abstract The mechanical properties of walnut (Juglans regia L.) and cherry (Prunus avium L.) woods, as frequent raw materials in cultural heritage objects, have been investigated as a function of the anatomical directions and the moisture content (MC). The strength data are decreasing with increasing MC, whereas the tensile strength in the longitudinal direction is higher by factors of 1.5–2 compared to the compression strength. Moreover, the inequality of tensile and compressive stiffness is discussed, which is a matter of debate since a long time. This so-called bimodular behavior is difficult to describe in a generalized mode due to the high data variability if tension and compression properties are analyzed on different samples. If tensile and compressive stiffness tests are performed on the same samples of walnut and cherry wood, the ratio between these properties is significantly higher than 1.