Level Set Methods for Multilayer Geological Folding Jonathan Boon, Chris Budd & Giles.Hunt

1. Level Set Methods for Multilayer Geological Folding Jonathan Boon, Chris Budd & Giles.Hunt

3. Motivating Examples

4. Experiments

5. Experiments on layers of paper (courtesy of Ahmer Wadee, Rorie Edmunds, Jonathan Boon)

6. In-between States

7. Model 1 • Euler strut • Energy • Critical Load depends on length of strut.

8. Model 2 • Strut on a linear elastic foundation – more realistic • Critical load • Wavelength

9. Model 3 • Viscous foundation • Biot: Dominant wavelength • Valid for small deflections. • Wavelength does not agree well with reality.

10. Δ P

11. Multilayer models • Two layer model developed (Budd et al. 2003). • Addition of friction to elastic foundation model. • Can not accurately extend to n layer model because outer layers become non-sinusoidal… • Use level set method to model the multilayer geometry.

12. Swallowtail Lagrangian formulation Eulerian formulation Serial folding

13. LSM applied to parallel fold

14. Comparison of model with experiment • Reformulate mechanical model in terms of the geometry

15. Conclusion • Singularity formation in multilayers can be predicted by the geometry. • Nonlinear bending energy provides a mechanism of restabilising a fold. • Serial folds form most naturally from the reactive end. • Further work needed to verify results and to check the effects of unmodelled behaviour