Issue 54

B. Bartolucci et alii, Frattura ed Integrità Strutturale, 54 (2020) 249-274; DOI: 10.3221/IGF-ESIS.54.18

than those of Spruce and in fact are contained in a range from 0.26 to 0.315. Also, the Fir (Subalpine) has a value less than Spruce that turns out to be equal to 0.341 (ID17 [25]). Concerning the value of the Poisson’s ratio LR, we can notice that for Spruce the error scatter from the average value of approximately 0.4 is quite high and it can reach the value of 0.55; instead, for the Pine wood in Fig. 14 is evident a sharp decrease in the Poisson’s ratio LR that turns out to be 0.13 caused by the low wood moisture content (MC) (ID4 [12]). Trends slightly higher than those of LT are recorded for other types of pine. Concerning the RT Poisson’s ratio, we generally notice an increase in the Poisson’s ratio compared to LR, both for the different types of pine and for some types of Spruce (e.g. spruce dry Norway ID13 [21], Sitka, and Engelmann ID18 [4]). The maximum recorded value is assumed by this latter specie and it is equal to 0.53. In the paper ID10 [18], it is noticed a strong reduction in the value of the RT Poisson’s ratio, very probably due to the type of specimen geometry, that provides the value of 0.21. Consequently, it is therefore rather difficult to establish a common pattern for the trend followed by this parameter on the examined woods population.

Figure 14: Scatterplot of density (kg/m 3 ) versus Poisson Ratio (pure number) for both softwood (Top plot) and hardwood (Bottom plot) species in LT (Black dots), LR (Dark grey dots), and RT (Light grey dots) directions.

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