Mr. Christos Prosgolitis, from the Numerical Modeling Dpt., successfully presented his PhD Thesis entitled “Experimental investigation and analytical modeling of fatigue crack growth in HSLA steels with pre-existing plastic deformation”.
The PhD thesis defense took place on December 5th, 2022, at the Department of Mechanical Engineering of the University of Thessaly before the Seven-Member Examining Committee, consisting of Assoc. Prof. Alexis Kermanidis (Supervisor, University of Thessaly), Prof. Spyros Karamanos (University of Thessaly), Prof. Nikolaos Aravas (University of Thessaly), Prof. Gregory Haidemenopoulos (University of Thessaly), Assist. Prof. Anna Zervaki (National Technical University of Athens), Prof. Carlo Castiglioni (Politecnico di Milano), Prof. Abílio de Jesus (University of Porto).
In the PhD, a combined experimental-numerical-analytical methodology was developed providing a basis for a better understanding of the fatigue crack growth behavior of plastically prestrained materials towards a more reliable assessment of fatigue damage evolution at critical locations of S355MC and S460MC steel sections manufactured by cold forming process.
In the experimental part, the effect of different plastic prestraining levels on the monotonic, cyclic and fatigue crack growth behavior of the S355MC and S460MC steels was evaluated.
In the numerical part, a FE Model was developed to calculate the magnitude and distribution of residual stresses and strains at the critical locations of the cold formed structural steel profile.
In the analytical part, prediction of fatigue crack growth rate (FCGR) in plastically prestrained materials under mode I loading based on an established critical energy approach was performed.