Fatigue failure mechanism of marine concrete structures using multi-scale numerical modelling (FAMCON)

ongoing

Floating substructures, e.g. floating offshore platforms, have widely been constructed from steel, as steel’s survivability in the marine environment is well-understood from its use in fixed-foundation offshore wind, but recent discussions in industry have suggested a shift towards the use of concrete due to its lower manufacturing costs, lower carbon footprint and better cost stability. However, lack of confidence in the use of concrete floating structures in a marine environment, particularly its structural performance under fatigue loading, has led to exacting design requirements to ensure their water tightness and durability, leading to excessive thickness that hinders their floatability. This FAMCON project aims to advance understanding of fatigue failure mechanisms of marine concrete using multi-scale numerical modelling, with novelty in integrating information across different scales - from the microstructure of the concrete material to the macroscopic structural response. The project will address the following challenges: 1) simulate micro-scale continuous hydration of cracked marine concrete under fatigue loading, to be able to evaluate the hidden benefit of seal-healing of concrete to its fatigue resilience which have been ignored previously; 2) simulate meso-scale crack propagation mechanism of defected concrete in order to develop the stress-strain constitutive model of concrete with random defects; 3) develop an integrated multi-scale numerical model to investigate probabilistic fatigue performance of marine concrete in order to provide a more realistic fatigue life prediction. This project will not only accelerate the technology readiness level for offshore renewable energies by improving understanding of fatigue life, but also contributes to the longevity and safety of critical marine infrastructure.