Guest speaker seminar of Prof. Ozgur Aslan, Associate professor, Mechanical Eng. Department, Atilim University, Ankara, Turkey : "Generalized continuum modeling of crack growth and failure in microstructures"

on 2/12 at 13h15 via Teams.

Abstract :

Proper life-time prediction modelling of engineering components manufactured from materials with complex microstructers are of increasing importance due to their enhanced mechanical properties and common use in industry. In that context, modelling of failure, considering continuum based viscoplastic damage approaches are of great interest ; however, mechanical properties of crystalline metals and smart alloys with advanced coating systems could be strongly anisotropic and non-linear. Coupling of harsh environmental conditions such as high temperature corrosive or hydrogen concentrated environments with severe mechanical loadings bring certain complexity to the constitutive and numerical modelling. This talk will first introduce a generalized continuum approach applied to continuum damage mechanics coupled to crystal plasticity and a numerical fatigue crack growth model will be presented within this frame-work. Regarding the issue of failures related with severe chemical environments, a coupled theory which accounts for diffusion and large elastoviscoplastic deformations will also be presented. Specifically, numerical efforts tackling with problems that involve anisotropic damage, macroscale shear-band formation, oxidation related failures will be shown and the application of generalized continuum approach to those constitutive models will be demonstrated as a powerful regularization technique.

References

[1] Aslan, O., and Forest, S., 2009. Crack growth modelling in single crystals based on higher order continua. Computational Materials Science, vol 45, pp 756-761.

[2] Aslan, O., Quilici, S., Forest, S., 2011. Numerical modeling of fatigue crack growth in single crystals based on microdamage theory. International Journal of Damage Mechanics. doi : 10.1177/1056789510395738

[3] Aslan, O., Cordero, N., Gaubert A., and Forest, S., 2011. The micromorphic approach to crystal plasticity and damage. International Journal of Engineering Science. doi:10.1016/j.ijengsci.2011.03.008

[4] Forest, S., 2009. Micromorphic approach for gradient elasticity, viscoplasticity and damage. ASCE Journal of Engineering Mechanics 135, 117-131.

[5] Sait, F., Gurses, E., Aslan, O, 2020. Modeling and Simulation of Coupled Phase Transformation and Stress Evolution in Thermal Barrier Coatings, International Journal of Plasticity, vol.134, pp.102790