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IMMC

Karim Ismail
PhD student
Ir. at UCL in 2014
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Main project: Characterization and physics based modeling of plasticity and fracture of Dual-Phase steels towards ultratough materials by microstructure optimization
Funding: Assistant
Supervisor(s): Thomas Pardoen, Pascal Jacques

The research work, in collaboration with company ArcelorMittal, is about the plasticity, the damage and the crack propagation resistance of dual-phase steels, which are commonly used in the automotive industry. A minimum level of fracture toughness is required to prevent the propagation during forming operations of small edge damage or cracked zones induced by cutting. Therefore, unravelling the relationship between fracture toughness, microstructure and damage mechanisms is essential to develop advanced steels with superior forming ability. Furthermore, reaching superior fracture toughness could open to other potential applications.
Experimental works as well as computational modeling are used to study the behavior of such steels. A model for the plastic behavior and for the damage mechanisms related to the microstructure has been developed. A finite element based unit cell approach is used to address the plastic behavior, locally as well as at the macroscopic scale. A particular focus is put on the effect of particle morphology and orientation that have not been much investigated and that considerably affect local mechanical fields, and hence damage and fracture behavior. A two-stage void coalescence process is suggested in elongated microstructures. The data extracted from the elastoplastic analysis are fed into a cellular automaton approach of the damage evolution. This model introduces a statistical description of the material while using relatively simple damage evolution laws. Furthermore, the essential work of fracture method is used to quantify the resistance to the propagation of a crack on thin sheets. Martensite morphology in the form of platelets seems to be a means to reach a high fracture toughness. Finally, damage mechanisms are observed post-mortem and hole expansion ratio tests will be performed.


IMMC main research direction(s):
Solid mechanics

Keywords:
metallic alloys
micromechanics
plasticity

Research group(s): IMAP
Collaborations: ArcelorMittal

    

Recent publications

See complete list of publications

Conference Papers


1. Croonenborghs, Maïté; Ismail, Karim; Everaerts, J; Korsunsky, AM; Pardoen, Thomas. Influence du pliage sur la resistance en fatigue des tiges de croissance. http://hdl.handle.net/2078.1/226259

2. Ismail, Karim; Pierman, Anne-Pascale; Pardoen, Thomas; Jacques, Pascal; Brassart, Laurence; Perlade, A.. Plasticity & Fracture Toughness of Fibrous Dual-Phase Steels for automotive Applications. http://hdl.handle.net/2078.1/173229