PSI - Issue 50

V. Ilinykh Artem et al. / Procedia Structural Integrity 50 (2023) 113–118 Illinykh Artem V. et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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Fig. 1. (a) Instron 2620-603 mounted extensometer; (b) tensile cylindrical samples.

Torsion experiments were carried out on an Instron Electropuls E10000 servo-electric test system. Due to the small size of the working area of the samples (20 mm) it is impossible to install a hinged shear strain gauge. Therefore, a three-dimensional digital optical system Vic-3D with a set of high-resolution cameras was used to measure shear strains (Fig. 2b). Figure 2a shows torsion cylindrical samples. Before the start of the experiment, paint is applied to the sample to obtain a contrast image in the working area of the sample. Next, the VIC 3D optical system is installed and calibrated to the sample surface. The twisting of the sample was carried out at a speed of 4 degrees per minute until the destruction of the sample. Based on the results of processing the obtained experimental data, the following mechanical characteristics were determined: shear modulus (G, GPa), proportionality limit ( τ pc, MPa), conditional yield strength ( τ 0.3, MPa) and ultimate strength ( τ b, MPa) in torsion.

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Fig. 2. ( а ) torsion cylindrical samples; ( б ) three-dimensional digital optical system Vic-3D with a set of high-resolution cameras

3. Results and discussions After testing according to the data obtained from the Instron 8801 testing system the deformation diagrams of the samples were built, shown in Figure 3a. According to GOST 1497-84 the mechanical characteristics of the material for samples grown at angles of 0, 30, 45, 60, and 90º to the substrate plane were obtained from the diagrams. The obtained values of mechanical characteristics are presented in table 1.