Abstract : In order to test the fluctuation-dissipation relation on rheological properties of soft materials, we built an experiment to measure thermally excited strain in a sample and compare it to the classical response to an external stress. The rheometer is based on a cylindrical Couette geometry. We use differential interferometry to achieve better than 10(-10) rad/rootHz sensitivity in angular position above 0.5 Hz. The forcing method, based on electrostatic interaction in a capacitor, generates torques comparable to that of thermal noise. Experiments on a calibrated silicon oil show good agreement between response and fluctuation measurements.
https://hal-ens-lyon.archives-ouvertes.fr/ensl-00179779
Contributeur : Ludovic Bellon
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Soumis le : mardi 16 octobre 2007 - 16:07:37
Dernière modification le : jeudi 19 avril 2018 - 14:54:03
Ludovic Bellon, Lionel Buisson, Sergio Ciliberto, Franck Vittoz. Zero applied stress rheometer. Review of Scientific Instruments, American Institute of Physics, 2002, pp.3286-3290. 〈10.1063/1.1499210〉. 〈ensl-00179779〉
