*MAT_024 (PIECEWISE_LINEAR_PLASTICITY)

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

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
MAT_024 or MAT_PIECEWISE_LINEAR_PLASTICITY
`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
`mat_ID`	Material Identifier (Integer)
$ρ_{i}$	Initial density (Real)	$[\frac{kg}{m^{3}}]$
`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)
`P`	Strain rate exponent (Real)
`LCSS`	Stress vs 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

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).
This material is only compatible with truss elements only when plasticity is specified through SIGY and ETAN.
The option “_TITLE” can be added to the end of this keyword. When “_TITLE” is included, an extra 80 character long line is added after the keyword input line which allows an entity title to be defined.