DruckerPragerMaterial

A multi-dimensional material model for Drucker-Prager plasticity defined by:

Parameters:

Parameter	Description	Type
k	Bulk modulus (required)	float
G	Shear modulus (required)	float
sigmaY	Yield stress (required)	float
rho	Frictional strength parameter (required)	float
rhoBar	Controls evolution of plastic volume change: 0 ≤ rhoBar ≤ rho (default = rho)	float
Kinf	Nonlinear isotropic strain hardening parameter: Kinf ≥ 0 (default = 0.0)	float
Ko	Nonlinear isotropic strain hardening parameter: Ko ≥ 0 (default = 0.0)	float
delta1	Nonlinear isotropic strain hardening parameter: delta1 ≥ 0 (default = 0.0)	float
delta2	Tension softening parameter: delta2 ≥ 0 (default = 0.0)	float
H	Linear strain hardening parameter: H ≥ 0 (default = 0.0)	float
theta	Controls relative proportions of isotropic and kinematic hardening: 0 ≤ theta ≤ 1 (default = 0.0)	float
density	Mass density of the material (default = 0.0)	float
atmPressure	Atmospheric pressure for updating elastic bulk and shear moduli (default = 101 kPa)	float

Example

# Direct creation
from femora.components.Material.materialsOpenSees import DruckerPragerMaterial
dp_material = DruckerPragerMaterial(
    user_name="Sand",
    k=8.33e6,      # Bulk modulus (Pa)
    G=3.85e6,      # Shear modulus (Pa)
    sigmaY=3000,   # Yield stress (Pa)
    rho=0.45,      # Frictional strength parameter
    rhoBar=0.4,    # Plastic volume evolution control
    Kinf=0.0,      # Isotropic hardening parameter
    Ko=0.0,        # Isotropic hardening parameter
    delta1=0.0,    # Isotropic hardening parameter
    delta2=0.0,    # Tension softening parameter
    H=500,         # Linear hardening parameter
    theta=0.5,     # Isotropic/kinematic hardening proportion
    density=1650   # Mass density (kg/m³)
)

or

# Via Femora
import femora as fm

fm.material.create_material(
    material_category="nDMaterial",
    material_type="DruckerPrager",
    user_name="Sand",
    k=8.33e6,
    G=3.85e6,
    sigmaY=3000,
    rho=0.45,
    H=500,
    density=1650
)