*MAT_121 (GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM)

LS-DYNA Input Interface KeywordDefines a nonlinear elasto-plastic discrete beam material with one degree of freedom (DOF). Different loading and unloading behavior can be specified.

Format

(1)	(2)	(3)	(4)
MAT_121 or MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM
`mat_ID`	$ρ_{i}$	`K`	`H`
`LCL`	`LCU`	`LCD`
`FAILT`	`FAILC`

Definition

Field	Contents	SI Unit Example
`mat_ID`	Material identifier. (Integer)
$ρ_{i}$	Initial density. (Real)	$[\frac{kg}{m^{3}}]$
`K`	Stiffness. (Real)	$[\frac{N}{m}]$
`H`	Unloading option. = 0 (Default) Elastic spring. = 1 Nonlinear unloading and isotropic hardening. = 2 Elastic hysteresis in unloading. = 3 Nonlinear elastic plastic spring with nonlinear unloading. (Real)
`LCL`	Curve identifier for force vs displacement loading curve. (Integer)
`LCU`	Curve identifier for force vs displacement unloading curve. (Integer)
`LCD`	Curve identifier for force vs velocity damping curve. (Integer)
`FAILT`	Failure elongation in tension. (Real)	$[m]$
`FAILC`	Failure elongation in compression. (Real)	$[m]$

Comments

This keyword maps to /MAT/LAW108 (SPR_GENE) with one degree of freedom (DOF).
DOF directions are defined by the coordinate system defined in *SECTION_BEAM. By default, the global coordinate system is used.
This material is only used with discrete beams ELFORM=6 and CA>0 in *SECTION_BEAM.
Beam elements with zero initial length are recommended.
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.