Issue 47

F. Cucinotta et alii, Frattura ed Integrità Strutturale, 47 (2019) 367-382; DOI: 10.3221/IGF-ESIS.47.27 379 The impact tests show that the peak force and the stiffness are nearly independent from the impact energy, as well known from literature [20,21]. The absorbed energy is very similar between A and B sandwiches, as long as the sandwiches are not yet damaged (damage degree less than 1). To the maximum energy level tested there is a difference between the specimens. The damage degree of the Specimen B is equal to 1 and this states a perforation and complete failure. Fig. 13 reports the comparison between numerical and experimental results, again in terms of load-displacement curve. Energy A sandwich B sandwich 20 J (a) (b) 40 J (c) (d) 60 J (e) (f) Figure 13 : A sandwich and B sandwich: FEA and Experimental comparison of impact tests at 20 J (a) and (b) , 40 J (c) and (d) , 60 J (e) and (f) . Load, kN Load, kN Load, kN Load, kN Load, kN Load, kN