Multi-approach study of crack-tip mechanics on aluminium 2024 alloy. (December 2018) - Chernyatin, A.S.
Highlights: Study of crack-tip propagation with macro-scale and micro-scale analyses. Experimental estimation of the crack-tip position and the crack orientation. Macro-scale analysis includes estimation of the SIF (continuum mechanics) from DIC. Micro-scale investigation includes fractography analysis with SEM. Full-field displacement information is combined with Williams' series development. Abstract: This work presents a comprehensive study for characterising the crack-tip mechanics and fatigue crack propagation in an Aluminium 2024-T351 alloy. It combines information obtained from three different sources: full-field displacement information from digital image correlation, analytical modelling of the crack-tip field and SEM fractographies. The displacement data measured around the crack-tip are fitted to a Williams' series development in order to evaluate singular and non-singular terms of the crack-tip field. The procedures also allows rigid body motion to be corrected and the crack-tip coordinates and crack orientation to be estimated. Fatigue striations from the fracture surface were analysed with SEM in order to estimate the crack growth rate for different boundary conditions. Representation of all the results together with the Paris law data of the alloy allows the procedures to be cross-validated and to fit with a good agreement micro-scale measurements with continuum mechanics estimations.