Issue 53

Y. Saadallah, Frattura ed Integrità Strutturale, 53(2020) 417-425; DOI: 10.3221/IGF-ESIS.53.32 421 domains. The slope of the densification domain exhibits the strongest nonlinearity by comparing it with the other two domains. Figure 4: Stress-strain curves in compression in the non-radial direction of cork at different densities. Density (gm 3 ) 0.2340 0.2477 0.2534 15.5 F (MPa) 2.85 3.33 3.45 D (MPa) 13.2 16.5 20  e . (MPa) 1.3 1.4 1.1  f . (MPa) 2.55 2.9 2.7  d at 66.9 % (MPa) 4.36 5.16 5.37 Table 1: Trilinear model parameters as a function of density. Fig. 6 shows the difference in absolute value between the experimental recordings and the model results for the three samples of different densities. There is a minimum difference in the elastic range and the buckling step with a maximum value of 0.14 MPa. However, the intersection of the straight lines of buckling and densification knows a significant gap that reaches 0.29 MPa. It retains its importance in the field of densification where it reaches its maximum value of 0.29 MPa as well. As a function of density, the highest difference is found in the densest sample. (a)