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Mechanical - Mechanical constitutive model

*Material, ... 
... 
*Mechanical = <mechanical model> 
*<parameter 1>, ... , <parameter n> 
...

Set this parameter equal to the mechanical model to be used for the calculation of stresses. The subsequent lines <parameter 1>, ... , <parameter n> depend on the model chosen. This parameter is mandatory. The different "mechanical" models available in numgeo are summarised in the table below and described in the subsections accessible through the links in the table or the navigation bar on the left.

Model Section
Linear Elasticity Linear elastic model
Mohr-Coulomb Linear elastic - perfectly plastic model with Mohr-Coulomb yield and failure criterion available in two different implementations
Matsuoka Nakai Linear elastic - perfectly plastic model with Matsuoka-Nakai yield and failure criterion
Modified Cam Clay Generalized Modified Cam-Clay (MCC) model with control over the shape of the yield surface and the stress ratio at critical state
Hypoplasticity + Intergranular Strain Hypoplastic model for sand according to von Wollfersdorff (1996)1 with intergranular strain extension (Niemunis and Herle, 1997)2
Hypoplasticity + Intergranular Strain Anisotropy Hypoplastic model for sand according to von Wollfersdorff (1996)1 with intergranular strain anisotropy extension (Fuentes et al., 2020)3
Sanisand Critical state compatible bounding surface plasticity model according to Dafalias & Manzari (2004)4 available in two different implementations
Sanisand-F Extension of the Sanisand model4 to incorporate effects of fabric by Petalas et al (2019)5
Sanisand-MSf Extension of the Sanisand model4 to incorporate effects of memory surface and semi-fluidized states according to Yang et al. (2022)6
AVISA Anisotropic Viscous ISA model after Tafili & Triantafyllidis (2020)7
AVHP Anisotropic Visco-Hypoplasticity (AVHP) as proposed by Niemunis & Grandas (2009)8
Hypo-Clay Hypoplastic constitutive model for clays proposed by Masin (2005)9
HCA for Sand High-Cycle Accumulation (HCA) model for sand as proposed by Niemunis et al. (2005)10. The current implementation allows coupling with the following models: Hypo-IGS, Hypo-ISA, Sanisand, Linear Elasticity
HCA for Clay High-Cycle Accumulation (HCA) model for clay11\(^,\)12. The current implementation allows coupling with the following models: AVISA, AVHP, MCC

References

  1. P.-A. Wolffersdorff. A hypoplastic relation for granular materials with a predefined limit state surface. Mechanics of Cohesive-frictional Materials, 1(3):251–271, 1996. doi:10.1002/(SICI)1099-1484(199607)1:3<251::AID-CFM13>3.0.CO;2-3. ↩↩

  2. A. Niemunis and I. Herle. Hypoplastic model for cohesionless soils with elastic strain range. Mechanics of Cohesive-frictional Materials, 2(4):279–299, 1997. doi:10.1002/(SICI)1099-1484(199710)2:4<279::AID-CFM29>3.0.CO;2-8. ↩

  3. William Fuentes, Torsten Wichtmann, Melany Gil, and Carlos Lascarro. ISA-Hypoplasticity accounting for cyclic mobility effects for liquefaction analysis. Acta Geotechnica, 15(6):1513–1531, 2016. URL: http://link.springer.com/10.1007/s11440-019-00846-2, doi:10.1007/s11440-019-00846-2. ↩

  4. Yannis F. Dafalias and Majid T. Manzari. Simple plasticity sand model accounting for fabric change effects. Journal of Engineering mechanics, 130(6):622–634, 2004. ↩↩↩

  5. Alexandros L. Petalas, Yannis F. Dafalias, and Achilleas G. Papadimitriou. SANISAND-F: Sand constitutive model with evolving fabric anisotropy. International Journal of Solids and Structures, 188–189:12–31, 04 2020. doi:10.1016/j.ijsolstr.2019.09.005. ↩

  6. Ming Yang, Mahdi Taiebat, and Yannis F. Dafalias. SANISAND-MSf: a sand plasticity model with memory surface and semifluidised state. Géotechnique, 72(3):227–246, 03 2022. doi:10.1680/jgeot.19.P.363. ↩

  7. M Tafili and T Triantafyllidis. AVISA: Anisotropic Visco ISA model and its performance at cyclic loading. Acta Geotechnica, 15:2395–2413, 2020. ↩

  8. A Niemunis, C E Grandas-Tavera, and L F Prada-Sarmiento. Anisotropic visco-hypoplasticity. Acta Geotechnica, pages 293–314, 2009. ↩

  9. D. Masin. A hypoplastic constitutive model for clays. International Journal for Numerical and Analytical Methods in Geomechanics, 29(4):311–336, 2005 2005. doi:10.1002/nag.416. ↩

  10. A Niemunis, T Wichtmann, and T Triantafyllidis. A high-cycle accumulation model for sand. Computers and Geotechnics, 32(4):245–263, 2005. doi:https://doi.org/10.1016/j.compgeo.2005.03.002. ↩

  11. T Wichtmann. Soil Behaviour Under Cyclic Loading: Experimental Observations, Constitutive Description and Applications. Habilitation, Institute of Soil Mechanics and Rock Mechanics, Karlsruhe Institute of Technology, Issue No. 181, 2016. ↩

  12. Patrick Staubach, Jan Machaček, Merita Tafili, and Torsten Wichtmann. A high-cycle accumulation model for clay and its application to monopile foundations. Acta Geotechnica, 17(3):677–698, mar 2022. doi:10.1007/s11440-021-01446-9. ↩