Nonlinear elasto-plastic material model for concrete plates and shells - Concrete2

Nonlinear elasto-plastic material model with hardening. Takes into account uniaxial stress + transverse shear in concrete layers with transverse stirrups. Can be used only for 2d plates and shells with layered cross section and together with explicit integration method (stiffness matrix is not provided). The model description and parameters are summarized in Tab. 18.

Table 18: Nonlinear elasto-plastic material model for concrete - summary.
Description Nonlinear elasto-plastic material model for concrete plates and shells
Record Format Concrete2 num(in) # d(rn) # E(rn) # n(rn) # SCCC(rn) # SCCT(rn) # EPP(rn) # EPU(rn) # EOPU(rn) # EOPP(rn) # SHEARTOL(rn) # IS_PLASTIC_FLOW(in) # IFAD(in) # STIRR_E(rn) # STIRR_Ft(rn) # STIRR_A(rn) # STIRR_TOL(rn) # STIRR_EREF(rn) # STIRR_LAMBDA(rn) #
Parameters - num material model number
  - d material density
  - E Young modulus
  - n Poisson ratio
  - SCCC pressure strength
  - SCCT tension strength
  - EPP threshold effective plastic strain for softening in compression
  - EPU ultimate eff. plastic strain
  - EOPP threshold volumetric plastic strain for softening in tension
  - EOPU ultimate volumetric plastic strain
  - SHEARTOL threshold value of the relative shear deformation (psi**2/eef) at which shear is considered in layers. For lower relative shear deformations the transverse shear remains elastic decoupled from bending. default value SHEARTOL = 0.01
  - IS_PLASTIC_FLOW indicates that plastic flow (not deformation theory) is used in pressure
  - IFAD State variables will not be updated, otherwise update state variables
  - STIRR_E Young modulus of stirrups
  - STIRR_R stirrups uniaxial strength = elastic limit
  - STIRR_A stirrups area/unit length (beam) or /unit area (shell)
  - STIRR_TOL stirrups tolerance of equilibrium in the z direction (=0 no iteration)
  - STIRR_EREF stirrups reference strain rate for Peryzna's material
  - STIRR_LAMBDA coefficient for that material (stirrups)
  - SHTIRR_H isotropic hardening factor for stirrups
Supported modes 3dShellLayer, 2dPlateLayer

Borek Patzak