Issue 47

L. Marsavina et al., Frattura ed Integrità Strutturale, 47 (2019) 266-276; DOI: 10.3221/IGF-ESIS.47.20 268 series. Orientation 1 corresponds to an out-of-plane loading, and orientation 2 corresponds to an in-plane loading direction. Typical force - displacement curves are shown in Fig. 2. It could be observed that for orientation 1, which is the one most used for PB, higher values of loads were obtained comparing with direction 2 and a quasi-brittle behavior Figure 1 : Three point bending specimen Figure 2 : Typical force - displacement curves Based on the EN 310 standard [40], the Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) were determined. The three point bending results are shown in Fig. 3. It could be observed that the maximum values of MOR and MOE were obtained for direction 1 and 16 mm thickness PB: 11.5 MPa, respectively 1782 MPa. The obtained values are in accordance with those from literature for PB, as follow: 11 MPa for MOR and 1725 MPa for MOE. In Fig. 3 boxes marked with 1 and 2 are related to sample orientation according to loading direction. a. Modulus of rupture b. Modulus of elasticity Figure 3 : Mechanical properties of particleboard Mode I fracture toughness tests Mode I fracture toughness tests were carried out on Single Edge Notched Bend (SENB) specimens [41], Fig. 4a loaded in three point bending using Zwick Roell Z005, at room temperature, under displacement control with a loading speed of 10 mm/min. The maximum load F max recorded during the tests was considered to calculate Mode I fracture toughness (K IC ) , given by Eq. (1): 0 2 4 6 0 100 200 300 400 500 Standard travel in mm Force in N 11.50 10.63 9.30 9.24 0 2 4 6 8 10 12 14 16_1 25_1 16_2 25_2 Modulus of rupture [MPa] Thickness [mm] 1 2 1782.0 1245.6 1406.7 1153.6 0 500 1000 1500 2000 2500 16_1 25_1 16_2 25_2 Modulus of elasticity [MPa] Thickness [mm] 1 2 25_1 25_2 16_2 16_1