PSI - Issue 39

Daniele Amato et al. / Procedia Structural Integrity 39 (2022) 582–598 Author name / Structural Integrity Procedia 00 (2019) 000–000

595

14

Figure 11 Specimen No. 4, non-proportional loading condition: 0_1_40_1.

5.2 Spurious results The experimental results for a phase shift of 90° were not consistent, with exception of those cases in which = 0.76 . In the case of specimens 0_1_90_1 and 1_1_90_1 ( = 1.31 ), Figure 12 and Figure 13 illustrate three different results for three different specimens undergoing the same loading conditions. Therefore, a unique deflection angle could not be determined.

Specimens 0_1_90_2 and 1_1_90_2 ( = 1 ) are shown in Figure 14. With regards to Figure 14 (a), it is possible to see that the fracture surface exhibit the same deflection angle at both free surfaces. Specimen 1_1_90_2, depicted in Figure 14 (b), shows on average a flat propagation across the complete thickness of the specimen with some wavy deflection very near the free surface. Figure 12 Three different experimental crack surfaces for loading conditions 0_1_90_1 .