The interplay of material and geometric instabilities in large deformation s of viscous rock

H. B. Muhlhaus (1) , L. Moresi (1) , Frédéric Dufour (1) , B. Hobbs (1)

1 CSIRO - Commonwealth Scientific and Industrial Research Organisation [Canberra]

We analyse folding phenomena in layered viscous rock in which we assume that the thickness of each layer is much smaller than characteristic structural dimensions. We derive constitutive relations and apply a computational simulation scheme suitable for problems involving very large deformations of layered viscous materials. We then consider buckling instabilities in a finite, rectangular domain. Embedded within this domain, parallel to the longer dimension we consider a stiff, layered beam under compression. We analyse folding up to 40% shortening. The effect of layering manifests itself in that appreciable buckling instabilities are obtained at much lower viscosity ratios (1:10) than required for the buckling of isotropic beams (roughly 1:500). The wavelength induced by the initial harmonic perturbation of the layer orientation seems to be persistent. A linear instability analysis is conducted to clarify the numerical results and also to examine the potential role of couple stresses on the folding process

Domaines: Mécanique [physics.med-ph]; Matériaux

H. B. Muhlhaus, L. Moresi, Frédéric Dufour, B. Hobbs. The interplay of material and geometric instabilities in large deformation s of viscous rock. IUTAM Symposium on Analytical and Computational Fracture Mechanics of Non-Homogeneous Materials, 2001, Cardiff, United Kingdom. pp.105-115, ⟨10.1007/978-94-017-0081-8_14⟩. ⟨hal-01009021⟩