Investigation of Fracture Mechanism in Single Point Incremental Forming of AA5052 Aluminum Alloy Using the Bao-Wierzbicki Damage Model

Document Type : Original Article

Author

• Ali Zahedi Dizajyekan

University of Mohaghegh Ardabili

10.22067/jacsm.2023.81834.1180

Abstract

Incremental sheet metal forming is one of the promising sheet forming processes, in which local nature of the applied forming forces and independency of the process on the die, induces higher formability in the sheet and increases flexibility of the process in producing intricated geometries. In current study, from damage mechanics window, one of the prominent features of the process, i.e. forming limits of AA5052 sheets has been investigated. For this purpose, firstly, Bao-Wierzbicki damage model is coded and implemented into Abaqus finite element program via VUMAT subroutine. The constants of the damage model, hardening model and Hill48 yield model have been obtained utilizing the uniaxial tensile experiments in three directions of 0º, 45º and 90º with respect to rolling direction. To examine the formability, truncated cone and pyramid geometries with variable increasing wall angles have been considered and the experimental tests and simulation of the process were conducted. Using the stress and strain distribution, fracture phenomena and onset of fracture were described. The results show that the sheet metal fractures before it reaches the designed final height, so that for the geometries of truncated pyramid and truncated cone, the fracture height is obtained 19.9 mm and 16.9 mm, respectively. Considering the sheet anisotropy properties in the process simulation, the fracture height of specimens was predicted with an average accuracy of 9%, and the results reveal that with excluding the anisotropy properties of the sheets, the prediction accuracy decreases. Also, an acceptable agreement was obtained in predicting the fracture location.

Keywords

• Incremental sheet forming
• damage model
• finite element
• stress analysis

Main Subjects

• Forming

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