PSI - Issue 47

Jaroslav Václavík et al. / Procedia Structural Integrity 47 (2023) 282–289 Author name / Structural Integrity Procedia 00 (2019) 000–000

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test rig, loaded with the vertical force is presented in Fig. 7b. The testing set-up including the level of testing force was derived using FEM calculation (Fig. 8a).

a) b) Fig.7 a) Selection of a structural node from the bottom of the bus frame, b) set-up for the fatigue test of this structural node – loading with the vertical force at the middle of the longitudinal beam

a) b) Fig. 8a) FEM model of the structural beam which was used for CFRP plate length and position optimalisation, b) Crack at the transversal weld under the CFRP plate during fatigue test

a) b) Fig. 9a) The history of the strain at the structural joint during the fatigue test at the end of the CFRP strip ( ε CFRP), on the steel before the end of the strip ( ε steel), and further at the bottom weld where the crack occurred ( ε max, ε a). The crack propagated slowly due to the glued CFRP tape, b) fatigue test results, referenced to stress at a location 10 mm in front of the butt weld. An increase in the fatigue strength of the hybrid node with glued CFRP strips can be seen.