*MAT_067 (NONLINEAR_ELASTIC_DISCRETE_BEAM)

LS-DYNA Input Interface KeywordThis keyword defines a non-linear elastic discrete beam material with 6 decoupled DOFs with an optional preload.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
*MAT_067 or *MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM
mat_ID	${\rho }_i$	T_r	T_s	T_t	R_r	R_s	R_t
TD_r	TD_s	TD_t	RD_r	RD_s	RD_t
FO_r	FO_s	FO_t	MO_r	MO_s	MO_t
FFAIL_r	FFAIL_s	FFAIL_t	MFAIL_r	MFAIL_s	MFAIL_t
UFAIL_r	UFAIL_s	UFAIL_t	TFAIL_r	TFAIL_s	TFAIL_t

Definition

Field	Contents	SI Unit Example
mat_ID	Material identifier (Integer, maximum 10 digits)
${\rho }_i$	Initial density (Real)	$\left[\frac{\text{kg}}{{\text{m}}^{\text{3}}}\right]$
T_r, T_s, T_t	Curve identifier for force vs displacement loading curve in the r, s, and t directions. (Integer)	$\left[\frac{\text{N}}{\text{m}}\right]$
R_r, R_s, R_t	Curve identifier for moment vs rotation loading curve in the r, s, and t directions. (Integer)	$\left[\frac{\text{N}•\text{m}}{\text{rad}}\right]$
TD_r, TD_s, TD_t	Curve identifier for force vs velocity damping curve in the r, s, and t directions (Integer)	$\left[\frac{\text{N • s}}{\text{m}}\right]$
RD_r, RD_s, RD_t	Curve identifier for moment vs rotational velocity damping curve in the r, s, and t directions (Integer)	$\left[\frac{\text{Nms}}{\text{rad}}\right]$
FO_r, FO_s, FO_t	Force preload in directions r, s, t	$\left[\text{N}\right]$
MO_r, MO_s, MO_t	Moment preload in directions r, s, t	$\left[\text{Nm}\right]$
FFAIL_r, FFAIL_s, FFAIL_t	Failure forces in directions r, s, t	$\left[\text{N}\right]$
MFAIL_r, MFAIL_s, MFAIL_t	Failure moments in directions r, s, t	$\left[\text{Nm}\right]$
UFAIL_r, UFAIL_s, UFAIL_t	Failure elongations in directions r, s, t	$\left[\text{m}\right]$
TFAIL_r, TFAIL_s, TFAIL_t	Failure rotation angles in directions r, s, t	$\left[\text{rad}\right]$

Comments

1. This keyword maps to /MAT/LAW108 (SPR_GENE).
2. The material is only used with *SECTION_BEAM, ELFORM = 6 discrete beam elements.
3. Beams with zero initial length are recommended.
4. Force vs displacement and moment vs angle curves can be specified in the 1st quadrant only. The spring will behavior in compression will be a mirror of the entered curve and so that compression and tension behavior will be the same.
5. The damping curve is symmetric in compression and tension and should be defined in the 1st quadrant starting with the point 0, 0.
6. If for a DOF both force-based and displacement-based failure is defined, then only the displacement failure will be used.
7. 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.