Fatigue life prediction of wire arc additively manufactured WAAM steel using finite element method
Faizan, Ali (2025)
Diplomityö
2025
School of Energy Systems, Konetekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe20251215118956
https://urn.fi/URN:NBN:fi-fe20251215118956
Tiivistelmä
This thesis focuses on the investigation of the fatigue behaviour of a wire arc additive manufactured (WAAM), low-alloy steel specimen subjected under a displacement controlled cyclic loading parameter. The aim of the study is to assess the fatigue life performance based on finite element analysis with focusing on strain-based failure mechanism. A bone-like geometry, typical of parts built by WAAM, was modelled and the part was subjected to full elastic-plastic material behaviour considering a bilinear isotropic hardening law.
Stress and strain distribution, which were extracted from critical regions, showed large plastic deformation and cyclic energy dissipation that is associated with low-cycle fatigue. Hysteresis response was applied to measure stabilized strain amplitudes that used as input in strain-life fatigue prediction. Damage evolution modelling was also able to assess damage initiation and propagation behaviour in correlation with continuum damage mechanics and Paris law fracture trends. Mesh sensitivity studies ensured numerical and physical consistency in the results.
The results prove that numerical simulation is an effective surrogate for physical testing in the fatigue analysis of WAAM. The methodology - validated and cost-effective way of predicting fatigue life, determining the critical stress zones and supporting design optimization in additively manufactured steel components.
Stress and strain distribution, which were extracted from critical regions, showed large plastic deformation and cyclic energy dissipation that is associated with low-cycle fatigue. Hysteresis response was applied to measure stabilized strain amplitudes that used as input in strain-life fatigue prediction. Damage evolution modelling was also able to assess damage initiation and propagation behaviour in correlation with continuum damage mechanics and Paris law fracture trends. Mesh sensitivity studies ensured numerical and physical consistency in the results.
The results prove that numerical simulation is an effective surrogate for physical testing in the fatigue analysis of WAAM. The methodology - validated and cost-effective way of predicting fatigue life, determining the critical stress zones and supporting design optimization in additively manufactured steel components.