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HEINZE Karsta
Autre(s) thème(s) de recherche ou rattachement(s) : - Matière Molle kmheinze
univ-montp.fr
0783174497
Domaines de Recherche: - Sciences de l'ingénieur/Mécanique/Mécanique des matériaux
- Sciences de l'ingénieur/Microélectronique
- Sciences du Vivant
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Productions scientifiques :
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On the effect of local sample slope during modulus measurements by contact-resonance atomic force microscopy 
Auteur(s): Heinze K., Arnould Olivier, Delenne Jean-Yves, Lullien-Pellerin V., Ramonda M., George M.
(Article) Publié:
Ultramicroscopy, vol. 194 p.78 - 88 (2018)
Texte intégral en Openaccess : 
Ref HAL: hal-01869770_v1
DOI: 10.1016/j.ultramic.2018.07.009
Exporter : BibTex | endNote
Résumé: Contact-resonance atomic force microscopy (CR-AFM) is of great interest and very valuable for a deeper understanding of the mechanics of biological materials with moduli of at least a few GPa. However, sample surfaces can present a high topography range with significant slopes, where the local angle can be as large as ± 50°. The non-trivial correlation between surface slope and CR-frequency hinders a straightforward interpretation of CR-AFM indentation modulus measurements on such samples. We aim to demonstrate the significant influence of the surface slope on the CR-frequency that is caused by the local angle between sample surface and the AFM cantilever and present a practical method to correct the measurements. Based on existing analytical models of the effect of the AFM set-up's intrinsic cantilever tilt on CR-frequencies, we compute the non-linear variation of the first two (eigen)modes CR-frequency for a large range of surface angles. The computations are confirmed by CR-AFM experiments performed on a curved surface. Finally, the model is applied to directly correct contact modulus measurements on a durum wheat starch granule as an exemplary sample.
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Numerical modeling of the tensile strength of a biological granular aggregate: Effect of the particle size distribution
Auteur(s): Heinze K., Frank Xavier, Lullien-Pellerin Valerie, George M., Radjai Farhang, Delenne Jean-Yves
Conference: International workshop on Powders and Grains (Montpellier, FR, 2017-07-03)
Actes de conférence: , vol. p. (2017)
Ref HAL: hal-01539472_v1
Exporter : BibTex | endNote
Résumé: Wheat grains can be considered as a natural cemented granular material. They are milled under highforces to produce food products such as flour. The major part of the grain is the so-called starchy endosperm.It contains stiff starch granules, which show a multi-modal size distribution, and a softer protein matrix thatsurrounds the granules. Experimental milling studies and numerical simulations are going hand in hand tobetter understand the fragmentation behavior of this biological material and to improve milling performance.We present a numerical study of the effect of granule size distribution on the strength of such a cementedgranular material. Samples of bi-modal starch granule size distribution were created and submitted to uniaxialtension, using a peridynamics method. We show that, when compared to the effects of starch-protein interfaceadhesion and voids, the granule size distribution has a limited effect on the samples’ yield stress.
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Quantification of the Effect of Surface Slope on Mechanical Measurements by Contact-Resonance AFM
Auteur(s): Heinze K., Arnould Olivier, Delenne Jean-Yves, Lullien-Pellerin Valerie, Ramonda Michel, George M.
(Affiches/Poster)
Forum des Microscopies à Sonde Locale (Juvignac, FR), 2017
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The Wheat Grain as a cemented granular material: Nanoscale investigation of its mechanical properties
Auteur(s): Heinze K., Delenne Jean-Yves, George M., Lullien-Pellerin Valerie
(Affiches/Poster)
3. International Conference on Structural Nano Composites (NANOSTRUC 2016) (Aberdeen, GB), 2016
Ref HAL: hal-01605556_v1
Exporter : BibTex | endNote
Résumé: The Wheat Grain as a cemented granular material: Nanoscale investigation of its mechanical properties. 3. International Conference on Structural Nano Composites (NANOSTRUC 2016)
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