2021

2021

*MAT_018 (POWER_LAW_PLASTICITY)

LS-DYNA Input Interface KeywordThis model expresses isotropic plasticity model with rate effects which uses a power law hardening.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
MAT_018 or MAT_POWER_LAW_PLASTICITY
`mat_ID`	$ρ_{i}$	`E`	`v`	`K`	`N`	`c`	`p`
`SIGY`	`VP`

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)	$[Pa]$
`v`	Poisson’s ratio (Real)
`K`	Yield stress (Real)	$[Pa]$
`N`	Plasticity hardening exponent Default = 1.0 (Real)	$[Pa]$
`c`	Strain rate coefficient = 0 (Default) No strain rate effect (Real)	$[\frac{1}{s}]$
`p`	Strain rate exponent Default = 1.0 (Real)
`SIGY`	Optional yield stress value (Real)	$[Pa]$
`VP`	Formulation for rate effects: = 0 Total strain rate = 1 Viscoplastic strain rate (Integer)
$ε_{p}^{m a x}$	Plasticity maximum stress Default = 10³⁰ (Real)

Comments

This keyword maps to /MAT/LAW44 (COWPER) + /FAIL/JOHNSON.
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.