PSI - Issue 53

Martin Stepanek et al. / Procedia Structural Integrity 53 (2024) 58–64 Kepka et al./ Structural Integrity Procedia 00 (2023) 000–000

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Cyclic tests were carried out with samples printed from MS1 steel with an alternating load cycle. Samples with geometry according to Fig. 1a were tested in torsion with a controlled torque load mode. Only part of the samples with geometry according to Fig. 1c were tested in force-controlled tension-compression loading mode. Part of the samples was tested in the mode of combined tension/compression-torque stress. Two loading paths were tested for combined loading: proportional loading with alternating cycle, see Fig. 4a, and a non-proportional loading with a constant value of the normal load, see Fig. 4b.

Fig. 4. Loading path: a) proportional loading, b) non-proportional loading with a constant value of the normal stress.

The 316L steel samples were tested in five loading modes. With alternating pure pull/pressure, passing pull and twisting, with load mode with controlled force, respectively with controlled torque. The remaining sample samples were tested in the mode of combined tension/compression-torsion stress. Two loading paths were tested for combined loading: proportional loading with alternating cycle, see Fig. 5a, and a non-proportional load with a phase shift of the torque and axial force by an angle of π /2, see Fig. 5b.

Fig. 5. Loading path: a) proportional loading, b) non-proportional loading with phase shift of torque and axial force.

Relatively representative sets of test samples were produced and tested for the selected materials, available production and testing equipment, verified process parameters of printing. Through the implementation of the test program, among other things, a set of sufficiently representative experimental data was obtained for the verification of the criteria included in the programming of fatigue life calculations under multiaxial loading.