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Papers by Guido Chiantoni

Research paper thumbnail of Elastoplastic constitutive modeling of metallic materials at finite strains: FEM numerical responses from different constitutive models

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

Research paper thumbnail of Experimental Study of the Effect of Triaxiality Ratio on the Formability Limit Diagram and Ductile Damage Evolution in Steel and High Purity Copper

International Journal of Material Forming, 2010

In this contribution, the effect of the stress state (by mean of the triaxiality ratio) on the eq... more In this contribution, the effect of the stress state (by mean of the triaxiality ratio) on the equivalent plastic strain at fracture is experimentally investigated for different steels and high purity copper in the range of triaxiality from 0 (pure torsion) up to 1.2. This range of stress state is particularly meaningful for the majority of the mechanical applications. The prediction on the formability limit diagram for proportional loading paths (i.e. with constant triaxiality) is verified in the framework of Continuum Damage Mechanics (CDM) using the Lemaitre-Chaboche's damage model. Furthermore the influence on triaxiality on the threshold plastic strain for damage initiation and for the critical damage at rupture is experimentally studied. The results are compared with the prediction of the aforementioned damage model. A very good agreement between experimental results and CDM prediction is achieved.

Research paper thumbnail of Experimental assessment of ductile damage in P91 steel at high temperature

International Journal of Damage Mechanics, 2013

Research paper thumbnail of Elastoplastic constitutive modeling of metallic materials at finite strains: FEM numerical responses from different constitutive models

Research paper thumbnail of Self-assembling of In(Ga)As/GaAs quantum dots on (N11) substrates: the (311)A case

Micron, 2000

We have investigated the In(Ga)As island formation, in the Stranski-Krastanov growth mode, on (31... more We have investigated the In(Ga)As island formation, in the Stranski-Krastanov growth mode, on (311)A GaAs substrates. The surface topography of InAs and InGaAs strained epilayers was studied by contact microscopies. The different substrate affects the overgrown island shape. In(Ga)As grown on (311)A gives rise to quantum wire-like islands. Quantum dots (QDs), but with highly anisotropic shapes, are the outcomes of InAs deposition. QD samples were also characterized by photoluminescence (PL) measurements. Correlation between optical and morphological properties was observed. ᭧

Research paper thumbnail of 3D island nucleation behaviour on high index substrates

Materials Science and Engineering: B, 2000

We present experimental data on InAs epitaxial layers grown on (N11)GaAs substrates showing that ... more We present experimental data on InAs epitaxial layers grown on (N11)GaAs substrates showing that the substrate orientation affects the critical thickness for the onset of quantum dot self-assembling. The samples under investigation were characterised via photoluminescence measurements. We observed a decrease of self-assembling critical coverage with increasing Miller index N of the substrate. The observed behaviour is induced in-island strain relaxation inhibition caused by the use of high index substrates for the growth.

Research paper thumbnail of Substrate orientation dependence of island nucleation critical thickness in strained heterostructures

Europhysics Letters (EPL), 1999

The two-dimensional to three-dimensional transition in highly strained InAs grown on high index (... more The two-dimensional to three-dimensional transition in highly strained InAs grown on high index (N11) GaAs substrates was investigated. The samples were characterised by photoluminescence measurements and atomic force microscopy. Controlled changes in the 2D/3D growth critical thickness have been observed by changing the substrate orientation. The results have been interpreted by means of an equilibrium model which takes into account the effects of substrate orientation. In-island strain relaxation, affected in a controlled way by substrate orientation, is found to play the major role in determining the critical thickness value.

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

Research paper thumbnail of Elastoplastic constitutive modeling of metallic materials at finite strains: FEM numerical responses from different constitutive models

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

Research paper thumbnail of Experimental Study of the Effect of Triaxiality Ratio on the Formability Limit Diagram and Ductile Damage Evolution in Steel and High Purity Copper

International Journal of Material Forming, 2010

In this contribution, the effect of the stress state (by mean of the triaxiality ratio) on the eq... more In this contribution, the effect of the stress state (by mean of the triaxiality ratio) on the equivalent plastic strain at fracture is experimentally investigated for different steels and high purity copper in the range of triaxiality from 0 (pure torsion) up to 1.2. This range of stress state is particularly meaningful for the majority of the mechanical applications. The prediction on the formability limit diagram for proportional loading paths (i.e. with constant triaxiality) is verified in the framework of Continuum Damage Mechanics (CDM) using the Lemaitre-Chaboche's damage model. Furthermore the influence on triaxiality on the threshold plastic strain for damage initiation and for the critical damage at rupture is experimentally studied. The results are compared with the prediction of the aforementioned damage model. A very good agreement between experimental results and CDM prediction is achieved.

Research paper thumbnail of Experimental assessment of ductile damage in P91 steel at high temperature

International Journal of Damage Mechanics, 2013

Research paper thumbnail of Elastoplastic constitutive modeling of metallic materials at finite strains: FEM numerical responses from different constitutive models

Research paper thumbnail of Self-assembling of In(Ga)As/GaAs quantum dots on (N11) substrates: the (311)A case

Micron, 2000

We have investigated the In(Ga)As island formation, in the Stranski-Krastanov growth mode, on (31... more We have investigated the In(Ga)As island formation, in the Stranski-Krastanov growth mode, on (311)A GaAs substrates. The surface topography of InAs and InGaAs strained epilayers was studied by contact microscopies. The different substrate affects the overgrown island shape. In(Ga)As grown on (311)A gives rise to quantum wire-like islands. Quantum dots (QDs), but with highly anisotropic shapes, are the outcomes of InAs deposition. QD samples were also characterized by photoluminescence (PL) measurements. Correlation between optical and morphological properties was observed. ᭧

Research paper thumbnail of 3D island nucleation behaviour on high index substrates

Materials Science and Engineering: B, 2000

We present experimental data on InAs epitaxial layers grown on (N11)GaAs substrates showing that ... more We present experimental data on InAs epitaxial layers grown on (N11)GaAs substrates showing that the substrate orientation affects the critical thickness for the onset of quantum dot self-assembling. The samples under investigation were characterised via photoluminescence measurements. We observed a decrease of self-assembling critical coverage with increasing Miller index N of the substrate. The observed behaviour is induced in-island strain relaxation inhibition caused by the use of high index substrates for the growth.

Research paper thumbnail of Substrate orientation dependence of island nucleation critical thickness in strained heterostructures

Europhysics Letters (EPL), 1999

The two-dimensional to three-dimensional transition in highly strained InAs grown on high index (... more The two-dimensional to three-dimensional transition in highly strained InAs grown on high index (N11) GaAs substrates was investigated. The samples were characterised by photoluminescence measurements and atomic force microscopy. Controlled changes in the 2D/3D growth critical thickness have been observed by changing the substrate orientation. The results have been interpreted by means of an equilibrium model which takes into account the effects of substrate orientation. In-island strain relaxation, affected in a controlled way by substrate orientation, is found to play the major role in determining the critical thickness value.

Research paper thumbnail of On the Consequences of the Adoption of the Zaremba–Jaumann Objective Stress Rate in FEM Codes

Archives of Computational Methods in Engineering, 2014

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