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/MAT/LAW109

Block Format Keyword Elasto-plastic material with isotropic von Mises yield criterion with plastic strain rate and temperature depending nonlinear hardening.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/MAT/LAW109/mat_ID/unit_ID
mat_title
ρi                
E ν            
Cp η Tref T0    
tab_ID_h tab_ID_t Xscale_h Yscale_h     Ismooth
tab_ID_ η Xscale_ η              

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

unit_ID (Optional) Unit Identifier.

(Integer, maximum 10 digits)

mat_title Material title.

(Character, maximum 100 characters)

ρi Initial density.

(Real)

[kgm3]
E Young’s modulus.

(Real)

[Pa]
ν Poisson’s ratio.

(Real)

Ismooth Choice of yield function interpolation versus strain rate.
= 1 (Default)
Linear interpolation.
= 2
Logarithmic interpolation (base 10).
= 3
Logarithmic interpolation (base n).

(Integer)

Cp Specific heat.

(Real)

[JkgK]

Tref Reference temperature.

Default = 293K (Real)

[K]
T0 Initial temperature.

Default = Tref (Real)

[K]
η Taylor-Quinney coefficient (fraction of plastic work converted to heat). Value between 0.0 and 1.0.

(Real)

tab_ID_ η (Optional) Table identifier defining scale factor for η depending on strain rate, temperature, and plastic strain. Value between 0.0 and 1.0.

(Integer Id)

tab_ID_h Table identifier for yield stress depending on effective plastic strain and strain rate.

(Integer)

Xscale_ η Abscissa scale factor (strain rate) for tab_ID_ η .

Default = 1.0 (Real)

[1s]
Xscale_h Abscissa scale factor (strain rate) for tab_ID_h.

Default = 1.0 (Real)

[1s]
Yscale_h Scale factor for ordinate (stress) for tab_ID_h.

Default = 1.0 (Real)

[Pa]
tab_ID_t Table identifier for quasi-static yield stress depending on effective plastic strain and temperature.

(Integer Id)

Example (Aluminum)

Comments

  1. Yield criterion using isotropic von Mises equivalent stress:(1)
    ϕ=σVMσy
  2. Yield stress hardening defined by tabulated input as:(2)
    σy=fh(εp,˙εp)ft(εp,T)ft(εp,Tref)
    Where,
    fh(εp,˙εp)
    Function table of yield stresses depending on plastic strain and plastic strain rate.
    ft(εp,T)
    Table ID of quasi-static yield function depending on plastic strain and temperature.
    Tref
    Reference temperature. Corresponds to conditions during experimental tests.
  3. In adiabatic conditions, the temperature is updated using:(3)
    T=T0+ηfη(εp,˙εp,T)ρCp

    Where, η is the constant Taylor-Quinney coefficient which may be modified by introducing scalar factor defined by function fη(εp,˙εp,T) .

    Otherwise, if /HEAT/MAT is present in the model, the temperature is imposed on all elements and cannot be updated using Equation 3.

    Function fη(εp,˙εp,T) may be one dimensional, two-dimensional, or three-dimensional, but the first abscissa is always strain rate and the second one may be only the temperature.