PSI - Issue 45

Dylan Agius et al. / Procedia Structural Integrity 45 (2023) 4–11 Dylan Agius et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4 (a) Grain 2 simulation results with the slip systems contributing to the localisation provided by the red lines and arrows; (b) Grain 2 lattice rotation angle field.

The kink band formation will impact the development of slip bands, therefore, it is important to understand how its formation is affecting the strain magnitude in regions of slip band formation. To do this, the strain within Grain 2 was analysed by extracting strain across a line of interest in the simulation and experiment. Results in Fig. 5 show the existence of areas across the grain where the magnitude is very similar, as indicated by the triangles. However, the circles in Fig. 5 highlight the areas within the grain where the simulated magnitude in strain deviates from the experiments. This deviation is caused by the slight difference in slip band orientation which is the consequence of the additional active slip system in the simulation contributing to the localisation. Therefore, future work will include investigating what is causing this additional slip system to activate and to what extent its activity is affecting the formation of slip bands.

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7. Conclusion A combined experimental and computational investigation into strain localisation occurring within -annealed Ti 6Al-4V is presented. Through this investigation, the following findings were made:  Using a nonlocal CP-FFT model, intergranular and transgranular slip bands were successfully predicted in locations across the ROI that were comparable with the DIC results.  Initial findings obtained from a deeper analysis of the simulation results suggest that the nonlocal CP-FFT model is capable of recognising the influence of a grain’s local environment on slip system activity within the grain. Additionally, the predicted magnitude of strain at locations across the grain were comparable to that measured experimentally.  Kink band formation remains incorrectly predicted by the model. This resulted in inaccurate locations of strain localisation which could affect the capability of the model to accurately predict crack initiation sites. This area of the crystal plasticity modelling requires further investigation and development. Fig. 5 Comparison of the experimental and simulated across Grain 2 where (a) is the simulated response, (b) is the experimental response and (c) is the value of along the red line traversing the grain as indicated in (a) and (b).