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Experimental mechanics at the micrometer scale : towards generalized continua

le 18 mars 2021
à 13h30

Fabien AMIOT, Chargé de recherche HDR CNRS, Institut de recherche FEMTO-ST.

Fabien AMIOT

Fabien AMIOT

Résumé :

Micrometer-sized objects are very specific from the mechanical point of view for two reasons:
Their surface/volume ratio is much larger than for the objects mechanical engineers are used to deal with. The consequence is that strong surface couplings have been evidenced, translating changes in the (electro-) chem- ical environment into mechanical deformation.
The geometric margins (compared to the dimensions) and the material homogeneity resulting from the usual processing techniques are very poor.
As a consequence, studying the mechanical behavior of micrometer-sized objects requires to overcome two main barriers:
To identify material constitutive laws at the micrometer scale and to quan- tify the role of the environment on the behavior;
To model chemo-mechanical couplings
when materials are heterogeneous and structures are poorly defined. This called for specific experimental developments over the last years, and it will first be shown through two examples that these developments also provide useful tools to approach the mechanical behavior of composite materials by providing infor- mation at the finer scale.
The development of multi-physical full-field measurements at the micrometer scale also challenged the modeling of surface chemo-mechanical couplings. This suggested the use of higher-grade elasticity instead of a Gurtin&Murdoch-like framework to describe surface effects, and these approaches will be compared on a very simple test case. Second-strain gradient elasticity will prove to be suited to the description of surface couplings. This will be shown to call for additional modeling developments, but also reveals the key role of the bulk ma- terial in the surface chemo-mechanical transduction, thus stressing the need for experimental approaches of higher-grade elasticity.
Type :
Séminaires - conférences
Lieu(x) :
Lien de connexion visioconférence :
ID de réunion : 869 5320 7881
Code secret : 053976

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