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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and fatigue strength under cyclic loading. Under quasi-static axial loading, the averaged maximum tensile force of 31 kN has been determined for E = 300 kJ/m and this decreases if the energy per unit length is increased. Due to the comparably low penetration depths, the weld seams unbutton under quasi-static loading. Under cyclic loading, the steel-aluminium adapters V1 of test series 6C show a higher fatigue strength of F a ( N f = 2ꞏ10 6 ) = 1.31 kN compared to lap joints, even though the averaged ratio of weld width to penetration depth is lower with w w / p d = 0.7, as reported in Möller et al. (2017). In order to fulfil the demands of ship design, a compact geometry of a steel-aluminium adapter is necessary. Therefore, a reduction of the adapter length to 70 mm according to the schematic presentation of the laser beamwelded adapter of variant 2 (V2) in Fig. 2(b) is realised and denoted as test series “6E”.

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Fig. 2. Laser beam welded adapters: (a) variant 1 (V1); (b) variant 2 (V2).

2.4. Explosive welded steel-aluminium adapters In addition to lap joints and adapters of the developed laser beam welding, specimens manufactured from explosive welded adapters, as already applied in shipbuilding, are investigated. Since explosive welded joints are laminar composites made of steel S355, unalloyed aluminium AlSi99 and aluminium alloy EN AW-6082, additional sheet metal had to be welded to the adapter. Afterwards, the specimen shape of Fig. 3(a) has been extracted by water cutting and the resulting flat specimen, Fig. 3(b), has been polished. According to Table 2, this test series has the abbreviation “Ex”.

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Fig. 3. Specimen manufactured from explosive welded adapters: (a) technical drawing (b) schematic 3D geometry.