Influence of fatigue testing frequency on fracture and crack propagation rate in additive manufactured metals using the extended finite element method

• M. Awd ^[1] ; F. Walther ^[1]
  1. [1] Chair of Materials Test Engineering (WPT) TU Dortmund University
• Localización: Revista española de mecánica de la fractura, ISSN-e 2792-4246, Nº. 4 (comunicaciones 5th Iberian Conference on Structural Integrity), 2022, págs. 189-194
• Idioma: inglés
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• Resumen

  • Due to advancements in machine systems and scanning methods, the usage of selective laser melted materials has risen in industrial applications, leading to almost full-density products. However, the creation of microstructure and porosity during the melting process results in inconsistency in the mechanical behavior of the components under cyclic loading.

    This research examines the influence of fatigue testing frequency on fracture and crack propagation rate in additive manufactured metals, using micro-computed tomography (µ-CT) to analyze three-dimensional defects and their sequential behavior under quasi-static, high-cycle fatigue (HCF), and very high-cycle fatigue (VHCF) conditions for AlSi10Mg and Ti-6Al-4V alloys. In addition to microstructural analysis of the influence of defects on fatigue failure, fatigue crack propagation under cyclic loading is simulated using the extended finite element method from internal porosity. This enables the calculation of fatigue crack propagation rates at 20 Hz and 20 kHz. The analysis indicated that there is a distinct difference in damage processes in HCF and VHCF, with the effect of frequency and porosity determining the damage mechanisms as well as crack propagation rate in both regimes.