Laurent Delannay
Recent publications

Within the field of solid mechanics, my research aims at an improved understanding of the influence of microstructure and damage on the deformability, the strength and the toughness of both natural and high-performance engineering materials. One important challenge is to address anisotropic, non-linear and possibly unstable responses resulting from microstructural changes in plastically deformed heterogeneous materials. To assist the interpretation of experimental observations, performed at various length scales, I develop original, physically-sound, constitutive models and apply them in computational predictions of the microscopic and macroscopic mechanical response. The fields of application span many engineering disciplines, among which mechanical manufacturing, biomechanics and structural integrity.

IMMC main research direction(s):
Computational science
Solid mechanics

finite elements
fracture mechanics
metallic alloys

Research group(s): MEMA

PhD and Post-doc researchers under my supervision:

Observation and modelling of the link between microstructure evolution and strength in plastically deformed and annealed metals with fine-scale twins
Fengxiang Lin

This project aims at advancing the current understanding of the evolution of microstructures and strength during plastic deformation of face centered cubic metals in which fine-scale twins influence the dislocation slip activity, the stored energy, and the subsequent annealing. The fine-scale twins can be mechanical twins (e.g. in TWIP steels and high-strain-rate deformed copper) or growth twins in electro-deposited films. These fine-scale twins increase anisotropy, which promotes microscopic shear banding during plastic deformation. This project will specifically address some fundamental questions:
- What is the influence of the interplay of dislocation slip and mechanical twinning on the occurrence of microscopic shear bands (MSBs)?
- What is the influence of MSBs on the deformed microstructure (incl. rotation of twin bundles), the internal stresses, and the stored dislocation density?
- How do hardening and internal stresses (incl. “back-stresses”) develop in small-size samples compared to bulk samples?
- How do structural heterogeneities from MSBs and twin bundles affect the subsequent annealing behavior?

Viscoplasticity and strain localization in metallic thin films
Guerric Lemoine

Metallic thin films are widely used in the microelectronic industry and for surface functionalization. Owing to their very fine microstructure, thin films generally suffer of a lack of ductility and are prone to creep at room temperature. To avoid such detrimental effects in applications, their mechanical behaviors have to be characterized and modeled. Combining both experiments and simulations, my doctoral research focus on the rate dependent plasticity and the strain localization of metallic thin films. The Lab-on-chip technique is used to characterize the yield stress, the ductility, the hardening behavior and the strain rate sensitivity of Ni thin films. A localized necking model is also developed, dedicated to thin films and nano crystalline metals which aims at accounting for strain gradient plasticity effects, for grain size dependent strength, rate sensitivity and the possible contribution of creep/relaxation mechanisms. A dislocation-based crystal plasticity model has also been developed in order to study the mechanical and creep/relaxation behavior of the polycrystalline Pd thin films with high initial defect concentration, obtained by M-S Colla during her PhD thesis.

Crystal plasticity modelling of thermomechanical fatigue in ITER relevant tungsten
Aleksandr Zinovev

Tungsten, selected as plasma-facing material for fusion reactors (such as ITER and DEMO), needs to possess high crack resistance and ductility under extreme operation conditions, such as high neutron flux and cyclic thermal load, which lead to material degradation. The objective of this project is to develop a finite element (FE) model capable to simulate mechanical behaviour of polycrystalline tungsten under tensile testing with the focus made on effect of test temperature and irradiation-induced defects. The input for the model is derived from experiments and lower-scale models, such as crystal plasticity (CP), molecular dynamics (MD) and dislocation dynamics (DD). A combination of FE and CP approach allows for investigation of mechanical behaviour of tungsten at the grain level.

The following scientific questions have to be addressed in the frame of this PhD project:

How does the heterogeneity of stress and strain within grains affect the cracking behaviour of tungsten under ITER-like heat loads? How can the impact of neutron irradiation defects be included in the CP model? What is the effect of texture on anisotropy of plastic deformation and fracture properties?

A macroscopic constitutive law, which describes plasticity of tungsten in the ITER-relevant temperature range, has already been constructed. Based on that, two papers have been published in peer-reviewed journals.

Numerical modeling of growth and remodeling in stented arteries
Colin Laville

The project aims to predict the evolution of the radial contraction of stented arteries using a continuum mechanics model, with application to bio-resorbable stent development. The capture of the stress state evolution in the artery wall requires a material model that includes:

- the modeling of the main constituents such as collagen, elastin and smooth muscles ;

- time dependent evolution such as growth and structural remodeling.

Some developed tools are also used to predict fracture in bended stainless steels.

Recent publications

See complete list of publications

Journal Articles

1. Lin, Fengxiang; Shi, Qiwei; Delannay, Laurent. Microscopic heterogeneity of plastic strain and lattice rotation in partially recrystallized copper polycrystals. In: International Journal of Solids and Structures, Vol. 184, p. 167-177 (2020). doi:10.1016/j.ijsolstr.2019.01.024.

2. Miotti Bettanini, Alvise; Ding, Lipeng; Mithieux, Jean-Denis; Parrens, Coralie; Idrissi, Hosni; Schryvers, Dominique; Delannay, Laurent; Pardoen, Thomas; Jacques, Pascal. Influence of M23C6 dissolution on the kinetics of ferrite to austenite transformation in Fe-11Cr-0.06C stainless steel. In: Materials & Design, Vol. 162, p. 362 - 374 (2019). doi:10.1016/j.matdes.2018.12.005; 10.1016/j.matdes.2018.12.005.

3. Delannay, Laurent; Lemoine, Guerric; Coulombier, Michaël; Pardoen, Thomas. Modelling creep induced by internal stresses in freestanding submicron Cu film. In: IOP Conference Series: Materials Science and Engineering, Vol. 580, p. 012003 (2019). doi:10.1088/1757-899x/580/1/012003.

4. Poddar, Shashi; Pereira de Sa, Pedro Miguel; Cai, Ronggang; Delannay, Laurent; Nysten, Bernard; Piraux, Luc; Jonas, Alain M. Room-Temperature Magnetic Switching of the Electric Polarization in Ferroelectric Nanopillars. In: ACS Nano, Vol. 12, p. 576-584 (2018). doi:10.1021/acsnano.7b07389.

5. Miotti Bettanini, Alvise; Hannard, Florent; Jacques, Pascal; Pardoen, Thomas; Guilleume, Badinier; Mithieux, Jean Denis; Delannay, Laurent. Residual ferrite in martensitic stainless steels: the effect of mechanical strength contrast on ductility. In: Materials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing, Vol. 731, p. 495 - 505 (2018). doi:10.1016/j.msea.2018.06.012.

6. Delannay, Laurent. Modeling of microscopic strain heterogeneity during wire drawing of pearlite. In: Procedia Manufacturing, Vol. 15, p. 1893-1899 (2018). doi:10.1016/j.promfg.2018.07.199.

7. Lin, Fengxiang; Marteleur, Matthieu; Jacques, Pascal; Delannay, Laurent. Transmission of {332}<113> twins across grain boundaries in a metastable beta-titanium alloy. In: International Journal of Plasticity, Vol. 105, p. 195-210 (2018). doi:10.1016/j.ijplas.2018.02.012.

8. Zinovev, Aleksandr; Terentyev, Dmitry; Dubinko, Andrii; Delannay, Laurent. Constitutive law for thermally-activated plasticity of recrystallized tungsten. In: Journal of Nuclear Materials, Vol. 496, p. 325-332 (2017). doi:10.1016/j.jnucmat.2017.09.044.

9. Zinovev, Aleksandr; Terentyev, D; Delannay, Laurent. Finite element analysis of heat load of tungsten relevant to ITER conditions. In: Physica Scripta : an international journal for experimental and theoretical physics, Vol. T170, p. 014002 (2017). doi:10.1088/0031-8949/2017/T170/014002.

10. Miotti Bettanini, Alvise; Delannay, Laurent; Jacques, Pascal; Pardoen, Thomas; Badinier, Guillaume; Mithieux, Jean-Denis. Influence of microscopic strain heterogeneity on the formability of martensitic stainless steel. In: AIP Conference Proceedings, Vol. 1896, p. 020010 (2017). doi:10.1063/1.5007967.

Conference Papers

1. Miotti Bettanini, Alvise; Laville, Colin; Mithieux, Jean-Denis; Parrens, Coralie; Jacques, Pascal; Pardoen, Thomas; Delannay, Laurent. Ductile to brittle failure transition under bending deformation of martensitic stainless steels.

2. Szyndler, Joanna; Delannay, Laurent; Muszka, Krzysztof; Madej, Lukasz. Numerical and experimental microscale analysis of the incremental forming process. In: AIP Conference Proceedings. Vol. 1896, p. 080006 (2017). doi:10.1063/1.5008086.

3. Miotti Bettanini, Alvise; Delannay, Laurent; Jacques, Pascal; Pardoen, Thomas. The Effect of Second Population NbC Carbides on The Shear Localisation in a Nb-Modified AISI 410 Stainless Steel.

4. Miotti Bettanini, Alvise; Delannay, Laurent; Jacques, Pascal; Pardoen, Thomas; Mithieux, Jean-Denis; Badinier, Guillaume. The Role of Chromium Carbides Volume Fraction on Plastic Instability Under Three-Point Bending Test in Martensitic Stainless Steel.

5. Lemoine, Guerric; Colla, Marie-Stéphane; Pardoen, Thomas; Delannay, Laurent. Dislocation and back stress dominated viscoplasticity in freestanding sub-micron Pd films.

6. Delannay, Laurent; Tacq, Jeroen; Barde, Didier; Seefeldt, Marc. Direct micro-to-macro modelling of the cold rolling of pearlitic steel. In: MATEC Web of Conferences. Vol. 80, no.2008, p. 5 (2016). E D P Sciences: (France) Les Ulis, 2016. doi:10.1051/matecconf/20168002008.

7. Lemoine, Guerric; Colla, Marie-Stéphane; Idrissi, Hosni; Pardoen, Thomas; Delannay, Laurent. Dislocation and back stress dominated viscoplasticity in free-standing sub-micron Pd films.

8. Lemoine, Guerric; Colla, Marie-Stéphane; Amin-Ahmadi, B.; Idrissi, Hosni; Schryvers, D.; Raskin, Jean-Pierre; Pardoen, Thomas; Delannay, Laurent. Study of creep/relaxation in nanocrystalline FCC thin films through internal-stress-actuated microtensile testing method.

9. Miotti Bettanini, Alvise; Delannay, Laurent; Jacques, Pascal; Pardoen, Thomas. Characterization and Modeling of Ductile Damage Accumulation in Martensitic Stainless Steel.

10. Miotti Bettanini, Alvise; Delannay, Laurent; Jacques, Pascal; Pardoen, Thomas; Badinier, G.; Mithieux, J.-D.. Characterization and modeling of ductile damage accumulation in martensitic stainless steels. In: Book of abstracts, 2015.

Book Chapters

1. Delannay, Laurent; Van Bael, Albert. Editorial: in Honor of Paul Van Houtte. In: International Journal of Plasticity , Elsevier, 2015. doi:10.1016/j.ijplas.2014.09.002.