Abstract

Understanding fatigue failure and developing computational models for its prediction is a longstanding challenge for scientists and engineers. This elusive endeavour is often complicated by the presence of residual stresses and material-environment interactions. However, increasing hardware capabilities and recent progress in the development of coupled physical models open the door to developing predictive computational models for fatigue crack nucleation and growth, the overarching aim of this proposal. To this end, I will build upon the emerging field of phase field fatigue and incorporate for the first time the role of residual stresses (RS) and environmental effects, with the aim of developing a tool capable of delivering failure predictions for more realistic operational conditions and increase the technological significance of computational analyses. The Phase Field Method (PFM) will be used as a computational platform to tackle complex cracking propagations. In PFM, cracks are described diffusively through a scalar phase-field variable that discriminates between intact and broken material points. The strain energy density approach will be coupled with PFM to predict the crack nucleation, whereas the eigenstrain theory will be used to model the effect of residual stresses in the components. A hydrogen concentration-dependent degradation function will be introduced in the fracture dissipation energy to incorporate the effect of hydrogen on the fracture process. The experiments will be performed to validate all the numerical developments. Eventually, this research work will provide an accurate, efficient, novel, and robust numerical tool that can predict crack nucleation and propagation in complex geometries of brittle and ductile materials subjected to fatigue loading. This tool will be able to estimate the effect of residual stresses and hydrogen ingress on fatigue failures.

Importo del progetto

Finanziamento: euro 150.000

Durata

·       16/12/2022

·       15/12/2025