FE simulation of the influence of plastic strain on hydrogen distribution during an U-bend test

- A finite element modeling of the U-Bend test is proposed.
- Mechanically affected hydrogen transport is accounted for.
- A parametric study a the U-Bend test is performed.
- Influence of fabric parameters on hydrogen absorption is shown.
- The need of the Finite Elements tools to fully understand this test is demonstrated.

During an U-bend test, used for the macroscopic characterization of hydrogen embrittlement of thin sheets, a flat metallic strip is first given an U-shape and then submitted to hydrogen cathodic charging. Finite element simulations of this test have been performed for iron, based on the hydrogen transport equation accounting for diffusion and trapping. Focus is made on the influence of the geometric parameters of the forming process on the mechanical fields and hydrogen repartition in the sample. The results exhibit the variations of the total amount of hydrogen in the sample during the transient and steady-state stages. This parametric study is expected to be useful for the experimental choice of relevant test geometric parameters.

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