Microstructure sensitive strain-based modelling of fatigue life for high-performing steel structures


Event details

Date and time 27.09.2019 12:1513:00  
Place and room
Speaker Prof. Heikki Remes, Aalto University, School of Engineering, Finland
Category Conferences - Seminars
A smooth weld geometry and only small imperfections are achievable using advanced manufacturing methods. And when crack-like imperfections are eliminated, increased fatigue life is expected because of the longer macro-crack initiation period. The modelling of this period is a challenge for the fatigue assessment of high-performing structures since conventional approaches only consider total fatigue life without distinction between crack initiation and propagation periods. To overcome this challenge, this presentation introduces a new microstructure sensitive strain-based fatigue life model. The model uses a cumulative fatigue damage model for the representative volume element (RVE), the size of which is defined from grain size statistics. In this way, the approach can model an arbitrary geometry shape and include the effect of material microstructure. By repeating the fatigue damage calculations for successive RVE steps, the model is also capable of modelling the fatigue damage process from the initial geometry up to the final fracture. Thus, the fatigue crack initiation, short crack growth and long propagation behavior are all considered as a continuous process in the same model. The introduced model is applied to various weld shapes, and the results are compared with experiments and existing local approaches.

Heikki Remes graduated as Doctor of Science in 2008 from Helsinki University of Technology. Since 2014, he works as a Professor in Marine Technology at Aalto University, School of Engineering. He has special expertise in theoretical modelling and experimental testing of high-performing steel and marine structures. His research focus is on light and efficient structures that utilize high strength materials and modern manufacturing technology for challenging marine environment. He has been involved in several national and international research projects that aim for fundamental understanding of fatigue and fracture, as well as tackling practical challenges in the analysis production of high-performing structures. His research covers characterization and analysis methods for complex structures from crystal behavior to continuum modelling. He has published approximately 100 scientific journal and conference papers. He is a member in International Ship and Offshore Structures Congress (ISSC) and International Institute of Welding (IIW).

Practical information

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