Issue 43

F. Berto et alii, Frattura ed Integrità Strutturale, 43 (2018) 1-32; DOI: 10.3221/IGF-ESIS.43.01 16 Figure 19: Synthesis by means of local SED of un-notched and V-notched specimens’ data. Dealing with Cu-Be alloy recently investigated, the fatigue data are plotted in terms of averaged strain energy density range over a control volume in Fig. 21 [122], considering a critical radius equal to 0.6 mm. Thanks to the SED approach it has been possible to summarize in a single scatterband all the fatigue data, independent of the specimen geometry, estimating also the characteristic radius for the considered material at high temperature. More recent data from 40CrMoV13.9 data from unnotched and notched specimens have been summarized by using the SED approach. On the basis of the experimental evidences of [123], the synthesis in terms of SED has been carried out up to 500°C considering the same critical radius used in Ref. [124] dealing with multiaxial fatigue tests performed on the same material ( R 0 =0.05 mm). In fact no reduction in the fatigue strength has been detected until 500°C both for unnotched and notched specimens. (a) (b) Figure 20: High temperature tests on plain (a) and notched specimens (b) .