M2S and M1S
M2S is a two surfaces mixed isotropic-kinematic hardening plasticity model for natural soils obtained by hierarchically extending the Modified Cam-Clay model to include an early development of non-linearity, improved memory of stress history, anisotropy and the effects of structure and its degradation with plastic straining.
M2S reduces to M1S when only a single yield surface is considered. This latter model is implemented in Plaxis with a fully implicit stress-point algorithm ensuring numerically stable and first-accurate solutions at the Gaussian point level even in presence of stronly non-linear material response.
References:
Amorosi, A., Kavvadas, M. (1999), ‘A plasticity-based constitutive model for natural soils: a hierarchical approach’, In D. Kolymbas editor, Constitutive Modelling of Granular Materials, Springer 413-438.
Kavvadas, M., Amorosi, A. (2000), ‘A constitutive model for structured soils’; Géotechnique 50 (3), 263-274.
Amorosi, A., Boldini, D. (2003), ‘Single surface hardening plasticity model for soft clays: mathematical formulation and implicit numerical integration.’, Proc. International Workshop on Geotechnics of Soft Soils / Theory and Practice, Noordwijkerhout, 153-158.
Amorosi, A., Boldini, D., Elia, G., Germano, V. (2005), ‘A generalised backward Euler scheme for the integration of a mixed isotropic-kinematic hardening model for clays’, 8h Int. Conference on Computational plasticity COMPLAS2005, Barcelona, Part2, 926-929.
For more information and to obtain the model, please contact:
Dr. Daniela Boldini University of Bologna Dept. of Chemical, Mining and Environmental Engineering via Risorgimento 2, 400136 Bologna (Italy) tel: +39-051-2093390 fax: +39-051-2093392 e-mail: daniela.boldini@unibo.it
Prof. Angelo Amorosi Technical University of Bari Dept. of Civil and Environmental Engineering Geotechnical Section Via E. Orabona 4, 70125 Bari (Italy) tel: +39 (0)80-5963693 fax: +39 (0)80-5963675 e-mail: a.amorosi@poliba.it
Please note: This model is available as a user-defined soil model. However, Plaxis does not accept any responsibility when using this DLL. Hence, the user needs to validate results obtained from this model by him/herself. Plaxis does not provide support on the use of this model.