The problem of a crack perpendicularly approaching a bimaterial interface is examined using both ... more The problem of a crack perpendicularly approaching a bimaterial interface is examined using both global and localapproaches to fracture. The global approach is based on the J-integral with a second parameter, Q, which scales the stress triaxiality ahead of the crack. The local approach is based on either brittle fracture(Beremin model ) or ductile fracture (Rice and Tracey model ).
The formation of cup-cone fracture in round bars and of slant fracture in plane strain specimens ... more The formation of cup-cone fracture in round bars and of slant fracture in plane strain specimens is studied using the finite element (FE) method. Constitutive models proposed by Rousselier [Nucl. Engng. Des. 105 (1987) 97] and by Gurson [Acta Metall. 32 (1984) 157] are used. The analysis takes into account viscoplasticity and void nucleation. Different indicators of localization are computed
ABSTRACT For High Temperature Steam Electrolysis (HTSE), gas tightness largely drives performance... more ABSTRACT For High Temperature Steam Electrolysis (HTSE), gas tightness largely drives performance and is a critical key to develop this technology. The main difficulties are due to the fact that gas tightness must be achieved at high temperature (similar to 800 degrees C) between metallic components and brittle ceramic materials. The typical sealing solution relies on glass-based seals despite a large number of drawbacks. Metallic solutions have also been studied but without specific developments as they may be too stiff and too hard to be used together with ceramics. A sealing solution based on a specific metallic seal has been developed and is presented here. Using specific tightness tests, it is shown that this new seal remains tight enough during cooling from 800 degrees C to 400 degrees C and that the cell electrolyte can sustain the seating load. This metallic seal offers an alternative solution for HTSE stacks.
International Journal of Solids and Structures, 2013
ABSTRACT A yield function for single crystals containing voids has been developed based on a vari... more ABSTRACT A yield function for single crystals containing voids has been developed based on a variational approach. This first yield function is phenomenologically extended by modifying the dependence on the mean stress and introducing three adjustable parameters. Unit cell finite element calculations are performed for various stress triaxiality ratios, main loading directions and porosity levels in the case of a perfectly plastic FCC single crystal. The three model parameters are adjusted on the unit cell calculations so that a very good agreement between simulation results and the proposed model is obtained.
The problem of a crack perpendicularly approaching a bimaterial interface is examined using both ... more The problem of a crack perpendicularly approaching a bimaterial interface is examined using both global and localapproaches to fracture. The global approach is based on the J-integral with a second parameter, Q, which scales the stress triaxiality ahead of the crack. The local approach is based on either brittle fracture(Beremin model ) or ductile fracture (Rice and Tracey model ).
The formation of cup-cone fracture in round bars and of slant fracture in plane strain specimens ... more The formation of cup-cone fracture in round bars and of slant fracture in plane strain specimens is studied using the finite element (FE) method. Constitutive models proposed by Rousselier [Nucl. Engng. Des. 105 (1987) 97] and by Gurson [Acta Metall. 32 (1984) 157] are used. The analysis takes into account viscoplasticity and void nucleation. Different indicators of localization are computed
ABSTRACT For High Temperature Steam Electrolysis (HTSE), gas tightness largely drives performance... more ABSTRACT For High Temperature Steam Electrolysis (HTSE), gas tightness largely drives performance and is a critical key to develop this technology. The main difficulties are due to the fact that gas tightness must be achieved at high temperature (similar to 800 degrees C) between metallic components and brittle ceramic materials. The typical sealing solution relies on glass-based seals despite a large number of drawbacks. Metallic solutions have also been studied but without specific developments as they may be too stiff and too hard to be used together with ceramics. A sealing solution based on a specific metallic seal has been developed and is presented here. Using specific tightness tests, it is shown that this new seal remains tight enough during cooling from 800 degrees C to 400 degrees C and that the cell electrolyte can sustain the seating load. This metallic seal offers an alternative solution for HTSE stacks.
International Journal of Solids and Structures, 2013
ABSTRACT A yield function for single crystals containing voids has been developed based on a vari... more ABSTRACT A yield function for single crystals containing voids has been developed based on a variational approach. This first yield function is phenomenologically extended by modifying the dependence on the mean stress and introducing three adjustable parameters. Unit cell finite element calculations are performed for various stress triaxiality ratios, main loading directions and porosity levels in the case of a perfectly plastic FCC single crystal. The three model parameters are adjusted on the unit cell calculations so that a very good agreement between simulation results and the proposed model is obtained.
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Papers by Jacques Besson