Issue 53

I. Monetto et alii, Frattura ed Integrità Strutturale, 53 (2020) 372-393; DOI: 10.3221/IGF-ESIS.53.29 380 Figure 3: Correction factors of the average transverse stiffness for isotropic materials (  =  =1) with varying Poisson ratio  =0,0.3. Results for matching on 0 N d are in Tabs. 3 and 9. Figure 4: Relative rotation compliance coefficients under symmetrical transverse forces for isotropic materials (  =  =1) with varying Poisson ratio  =0,0.3. In Figs. 3 to 8 the results based on Timoshenko beam theory (continuous lines in all figures) are shown as functions of the relative thickness-wise position  of the delamination. Results obtained using the simplified model based on Euler- Bernoulli beam theory are presented in Figs. 3 and 9 to 11 (dashed lines). Fig. 3 shows the correction factors k w and EB w k evaluated for isotropic materials (  =  =1 and  xz =  zx =  ) on varying the Poisson ratio  =0,0.3. Figs. 4-11 show the root rotation and root displacement compliance coefficients obtained using Timoshenko and Euler-Bernoulli beam theory and the previously matched correction factors in isotropic and degenerate orthotropic specimens with  =1 and  =0.5. The matching coefficient is shown in the diagrams using triangle marks for 0 V d , circle marks for 0 M d and square marks for 0 N d ; the compliance coefficients derived using 2D elasticity in [3] and used for the matching are shown by dashed-dot lines and presented in Table 10. The diagrams, along with the equations in the previous section, highlight the features of the approach, its strengths and weaknesses.