Issue 43

D. Gentile, Frattura ed Integrità Strutturale, 43 (2018) 155-170; DOI: 10.3221/IGF-ESIS.43.12 167 Parameter Value Error A 0.1814411 0.0126216 B 0.0030053 7.08419E-4 R SD N P 0.8846366 0.0213166 7 0.0081516 Table 7: Linear regression for M30-1:   y A Bx In Fig. 15 and in Tab. 8 are reported the results for material designed M30-8 Figure 15: M30-8 Summary of crack resistance data. Parameter Value Error A 0.2910397 0.081719 B 0.0044296 0.0034419 R SD N P 0.4988296 0.1242753 7 0.2544621 Table 8: Linear regression for M30-8:   y A Bx A summary of strain energy release rates for DCB tested materials is reported in Fig. 16. A summary of strain energy release rates for DCB tested specimens vs. thickness is reported in Fig. 17. There is no distinction about materials but only different thickness of the samples. In Fig. 18 is reported a sample of bridging fibers in DCB specimens. ENF specimens In the following, similarly to the DCB results, the ENF data, for each specimen tested, are given. For what concerning G II , in addition to the value calculated with the relationship given in the prescription EN6034, other two values, the nonlinear and visual nonlinear, are also given, Fig. 4a. As discussed in the previous paragraph, the crack propagation resulted to be unstable for all specimens tested and only a single value of G II could be determined since, after the propagation, the crack extends up to the specimen midspan L where no further propagation is possible. The results are summarized in Tab. 9.