A hypoplastic model for sand
Download package contains two umats, one for basic hypoplasticity (von Wolffersdorff, 1996) and the other for hypoplasticity with small strain stiffness (Niemunis and Herle, 1997). The umats are associated with the following two publications, also included within the download package:
- Fellin and Ostermann (2002) – basic model
- Fellin, Mittendorfer and Ostermann (2009) – model with small strain stiffness
Associated papers and ABAQUS examples are included within the download package.
Fellin, W.; Ostermann, A. (2002): Consistent Tangent Operators For Constitutive Rate-Equations. In: International Journal for Numerical and Analytical Methods in Geomechanics 26/12, pp. 1213 – 1233.
Fellin, Wolfgang; Mittendorfer, Markus; Ostermann, Alexander (2009): Adaptive integration of constitutive rate equations. In: Computers and Geotechnics 36/5, pp. 698 – 708.
Niemunis A and Herle I. (1997). Hypoplastic model for cohesionless soils with elastic strain range. Mechanics of Cohesive-Frictional Materials 2, 279-299.
von Wolffersdorff, P. A. (1996). A hypoplastic relation for granular materials with a predefined limit state surface. Mechanics of Cohesive-Frictional Materials 1, No. 3, 251-271.