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Experimental modelling of deformation around rigid particles in pure shear: The impact of layer anisotropy

2016; Issue: 60 Linguagem: Inglês

2173-6545

Ramón Pascual, Elena Druguet, Jordi Carreras,

Planetary Science and Exploration

espanolEste trabajo se centra en como la rotacion de particulas rigidas esta influenciada por la anisotropia planar previa del medio envolvente durante la deformacion. Se llevaron a cabo tres experimentos en el Laboratorio de Deformacion de la UAB utilizando el aparato BCN-Stage. Los modelos se realizaron con material analogico (plastilina para la matriz y parafina para las inclusiones rigidas), siendo deformados por cizalla pura a tasa de deformacion y temperatura constantes. Todas las inclusiones eran inicialmente identicas en orientacion y dimension. En el primer experimento, cuya matriz consistio en plastilina homogenea, la rotacion de las particulas rigidas se produjo de acuerdo con la prevista por los modelos teoricos. En los otros dos experimentos, las particulas rigidas se encontraban inmersas en un sistema multicapa de plastilina sometido a plegamiento. Las capas en ambos experimentos tenian vergencias inicialmente opuestas con respecto a los ejes cinematicos. En estos dos casos, las inclusiones rigidas giran antiteticamente con respecto a las capas en plegamiento, independientemente de su orientacion, lo cual indica la fuerte influencia de la anisotropia de las capas y su orientacion en la rotacion de los cuerpos. Los resultados se pueden correlacionar con ejemplos de campo EnglishThis work focuses on how the rotation of rigid particles is influenced by preexisting planar anisotropy of the bounding media during deformation. Three experiments were conducted at the UAB Laboratory of Deformation using the apparatus BCN-Stage. The models were made with analogue materials (plasticine as the matrix and paraffin as rigid inclusions) and were deformed by pure shear at constant bulk strain rate and temperature. All inclusions were initially identical in orientation and dimension. In the first experiment, in which the matrix consisted of homogeneous plasticine, rotation of the rigid particles agreed with that of previous theoretical an experimental models. In the other two experiments, the rigid paraffin particles were embedded in multilayers of plasticine subjected to folding. The multilayers in both experiments had opposite initial vergences with respect to the kinematic axes. In these two cases, rigid inclusions rotate antithetically with respect to the layers that are being folded, regardless of their initial orientation, indicating the strong influence of layer anisotropy and its orientation on the rotation of rigid objects. The experiments can be correlated with natural field examples at multiple scales, from single crystals in metamorphic rocks to plutons.