PSI - Issue 54

T. Fekete et al. / Procedia Structural Integrity 54 (2024) 314–321 Investigation on geometric imperfections… Structural Integrity Procedia 00 (2019) 000–000

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Fig. 7. Geometric evolution of F1 (top) and its Digital Twin (bottom) during the test

In Figure 7, plot 'b', the DT indicates that the strain field is approximately homogeneous along the gauge length, but the distribution shows a slight asymmetry towards the two ends of the specimen. According to plot 'c', the DT provides a qualitatively correct, quantitatively acceptable approximation of the asymmetric location of the necking region. Plot 'd' is also evidence of this. Simulation predicts the position of the minimum cross-section of the necking to be slightly closer to the specimen head than observations show ( DT predicts this to be +10 mm from the initial symmetry plane –see Figure 5 left–, while observations show it to be +8.3 mm, with an error of 20.5%). In Figure 8, plot 'b', DT already shows that the strain field is slightly inhomogeneous along the gauge length, but this is not yet detectable with unaided eyes. Plot 'c' shows that DT provides a very good estimate for the necking region. Plot 'd' also shows that the DT is very accurate in predicting the location of the necking region. Simulation estimates the minimum cross-section of the necking to be located slightly further inwards from the head than observations indicate ( DT predicts this cross-section to be at –11.5 mm from the initial symmetry plane –see Figure 5 right–, while observations show it to be at –12 mm; the difference is 5%).

Fig. 8. Geometric evolution of F2 (top) and its Digital Twin (bottom) during the test