Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 45: Topical Session (Symposium MM): Fundamentals of Fracture
MM 45.5: Vortrag
Mittwoch, 14. März 2018, 18:15–18:30, TC 006
A multi-physics approach to investigate the effect of hydrogen on short fatigue crack growth — •Volker Schippl1, Sven Brück1, Hans-Jürgen Christ1, and Claus-Peter Fritzen2 — 1Institut für Werkstofftechnik, Universität Siegen, 57068 Siegen, Germany — 2Institut für Mechanik und Regelungstechnik - Mechatronik, Universität Siegen, 57068 Siegen, Germany
Hydrogen leads to a macroscopic embrittlement and under cyclic loading to increasing crack growth rate and a shorter fatigue life of mechanically loaded components. To address this problem, a better understanding of the hydrogen damaging mechanism is needed.
As the short crack propagation could dominate the whole fatigue life, a two-dimensional model is presented to simulate short crack propagation to get a better understanding of the fundamental mechanisms leading to failure. The model includes intergranular and transgranular crack growth and considers the plastic deformation along shear bands. The hydrogen concentration in the microstructure is calculated and the amount of the local hydrogen at the crack tip changes the crack growth mechanism. This multi-physics problem is addressed by using a sequential staggered BEM & FEM approach. At first, stresses and displacements are calculated by using a boundary element method. Based on the calculated hydrostatic stress field, the redistribution of hydrogen is determined using a finite element method. With this approach, it could be found that hydrogen leads to an increasing part of the irreversible plastic deformation at the crack tip which results in increasing crack growth rates and thus to shorter lifetime.