PSI - Issue 68

Tuncay Yalçinkaya et al. / Procedia Structural Integrity 68 (2025) 325–331 Yalc¸inkaya et al. / Structural Integrity Procedia 00 (2024) 000–000

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4. Conclusion

A comprehensive evaluation of ten uncoupled damage criteria in predicting fracture initiation and formability limits during flow forming is conducted for IN718 alloy. The experimental forming limit of the part, which is tested at 3 di ff erent reduction ratios of 37.5%, 50% and 70%, is found to be just above 50% as cracks begin to appear on its outer surface. Various tensile tests and their FE analyzes are performed for calibration the damage models to be used in comparison. The results indicate that the fracture prediction capacities of the KH and RT models are high in various stress states. Through detailed FE simulations and experimental comparisons, the Ayada model demonstrates superior performance in accurately predicting failure at various thickness reduction ratios. Although the KH model predicts cracks on the inner surface in a small area, it also has a good prediction capacity like Ayada. 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