*MAT_024 (PIECEWISE_LINEAR_PLASTICITY)

LS-DYNA Input Interface KeywordDefines an isotropic elasto-plastic material using tabulated stress versus plastic strain input for different strain rates.

Format

(1) (2) (3) (4) (5) (6) (7) (8)
*MAT_024_{OPTION} or *MAT_PIECEWISE_LINEAR_PLASTICITY_{OPTION}
mat_ID ρ i E υ SIGY ETAN FAIL
C P LCSS LCSR VP
EPS1 EPS2 EPS3 EPS4 EPS5 EPS6 EPS7 EPS8
ES1 ES2 ES3 ES4 ES5 ES6 ES7 ES8

Definition

Field Contents SI Unit Example
OPTION
<BLANK> (Default)
Linear strain rate interpolation between stress-strain curves.
LOG_INTERPOLATION
Logarithmic strain rate interpolation between stress-strain curves.
mat_ID Material identifier.

(Integer)

ρ i Initial density.

(Real)

[ kg m 3 ]
E Young’s modulus.

(Real)

[ Pa ]
υ Poisson’s ratio.

Default = 0 (Real)

SIGY Yield stress, ignored if LCSS > 0 or stress-strain values EPS1-EPS8, ES1-ES8 specified.

(Real)

[ Pa ]
ETAN Plastic hardening modulus, not used if LCSS > 0.

(Real)

[ Pa ]
FAIL Plastic strain to failure.

(Real)

C Strain rate coefficient.

(Real)

[ 1 s ]
P Strain rate exponent.

(Real)

LCSS Stress versus plastic strain curve or table identifier.

(Integer)

[ Pa ]
LCSR Curve identifier defining the scaling coefficient for the stress-strain curve for a corresponding strain rate.

(Integer)

VP Strain rate type flag:
0
Total strain rate.
1
Plastic strain rate.

(Integer)

EPS1-EPS8 Plastic strain data points.

(Real)

ES1-ES8 Yield stress data points.

(Real)

[ Pa ]

Comments

  1. This keyword maps to /MAT/LAW36 (PLAS_TAB) when stress-strain curves are specified using LCSS or EPS and ES. If SIGY, ETAN, C, and P are used, then it maps to /MAT/LAW44 (COWPER).
  2. This material is only compatible with truss elements only when plasticity is specified through SIGY and ETAN.
  3. The option “_TITLE” can be added to the end of this keyword. When “_TITLE” is included, an extra 80 characters long line is added after the keyword input line which allows an entity title to be defined.