PSI - Issue 18

Benjamin Möller et al. / Procedia Structural Integrity 18 (2019) 556–569 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fatigue tests have been performed under cyclic tensile pulsating loading (load ratio of R = 0) on servohydraulic test rigs at room temperature until total rupture of the specimen. Except for some tests of series 1E_KO, where the effect of exposure time of the corrosive media on the fatigue life of controlled-welded lap joints with a single weld is investigated, a test frequency of 30 Hz has been applied in all of the experiments. Fatigue tests of controlled-welded steel-aluminium adapters V2 under the influence of the corrosive media have exclusively been executed at 30 Hz. In addition to constant amplitude loading (CAL, also referred to as Wöhler tests ), variable amplitude loading (VAL, Gaßner tests ) using a linear spectrum has been applied to laser beam welded adapters V2 (test series 6E_VA). Additionally, two fatigue tests have been performed on explosive welded adapter specimens. An overview of the test program is given in Fig. 4. Denotations and characteristic details of each fatigue test series are documented in Table 3.

Fig. 4. Fatigue investigations on corresponding specimen types under constant amplitude loading (CAL) and variable amplitude loading (VAL) and optional corrosive environment

Table 3: Overview of characteristic details of test series for fatigue testing of lap joints with one and three weld seams, adapter specimens with six weld seams and explosive welded adapter specimens Test series Specimen type Number of weld seams Load ratio Loading type Environ- ment Remark (TS) R [-] 1A LBW lap joint 1 0.0 CAL air E = 300 kJ/m 1B LBW lap joint 1 0.0 CAL air E = 360 kJ/m 1C LBW lap joint 1 0.0 CAL air E = 300 kJ/m 1D LBW lap joint 1 0.0 CAL air oscillated 1E_KA LBW lap joint 1 0.0 CAL air controlled 1E_KO LBW lap joint 1 0.0 CAL corrosion 5%-NaCl 3B LBW lap joint 3 0.0 CAL air E = 360 kJ/m 3C LBW lap joint 3 0.0 CAL air E = 300 kJ/m 6C LBW adapter ‘V1’ 6 0.0 CAL air E = 300 kJ/m 6E_KA LBW adapter ‘V2’ 6 0.0 CAL air controlled 6E_VA LBW adapter ‘V2’ 6 0.0 VAL air linear spectrum 6E_KO LBW adapter ‘V2’ 6 0.0 CAL corrosion 5%-NaCl Ex explosive welded - 0.0 CAL air