Investigation of the formability of ductile sheet materials under non-proportional loading with consideration of the anisotropic damage behaviour
Final Report Abstract
As part of the project, the influence of uniaxial pre-forming and pre-forming in the plane strain range on the formability and damage development of the two sheet materials AA6016-T4 and DP600 was investigated. It was found that the aluminium material is significantly less affected by a change in the direction of loading than the steel material. On the one hand, the yield strength of DP600 decreases significantly more than that of AA6016-T4. On the other hand, the formability of the DP600 also decreases significantly more. This is particularly true for the uniaxial pre-forming states. This behaviour was shown to be caused by pre-forming leading to the development of dislocation structures. If a change in the load direction occurs, these structures must be realigned. This results in the cancellation of the existing dislocation structures. This leads to plastic instability and therefore to early failure of the material after a change in the load direction. However, in order to trigger plastic instability, the structures must be sufficiently large and stable. Therefore, the decrease in formability only occurs above a certain pre-forming level. This was clearly demonstrated by means of tensile tests with different pre-forming levels.
Publications
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Experiments on forming behaviour of the aluminium alloy AA6016. IOP Conference Series: Materials Science and Engineering, 1238(1), 012023.
Norz, R.; Valencia, F.R.; Gerke, S.; Brünig, M. & Volk, W.
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Influence of Loading Direction on the Mechanical Parameters of Pre-formed Materials in Tensile Test. The Minerals, Metals & Materials Series, 899-908. Springer International Publishing.
Norz, R. & Volk, W.
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Prediction of Necking Initiation in Case of Abrupt Changes in the Loading Direction. The Minerals, Metals & Materials Series, 617-625. Springer International Publishing.
Norz, R.; Manopulo, N.; Sigvant, M.; Chezan, A. R. & Volk, W.
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Damage and fracture in thin metal sheets: New biaxial experiments. Advances in Industrial and Manufacturing Engineering, 7, 100129.
Gerke, Steffen; Valencia, Fabuer R.; Norz, Roman; Volk, Wolfram & Brünig, Michael
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Ductile damage and failure of thin sheet metals: New biaxial experiments and numerical simulations. PAMM, 23(2).
Gerke, Steffen; Valencia, Fabuer R. & Brünig, Michael
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Investigation of the influence of loading direction after pre-forming on the formability and mechanical properties of DP600. Materials Research Proceedings, 28, 747-754. Materials Research Forum LLC.
NORZ, R.
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Determination of the onset of yielding and the Young’s modulus after a change in the loading direction. International Journal of Material Forming, 17(3).
Norz, Roman; Vitzthum, Simon; Gruber, Maximilian; Maier, Lorenz; Kornmeier, Joana Rebelo; Maawad, Emad; Valencia, Fabuer R.; Gerke, Steffen; Brünig, Michael & Volk, Wolfram
