*MAT_068 (NONLINEAR_PLASTIC_DISCRETE_BEAM)

LS-DYNA Input Interface KeywordDefines a nonlinear elasto-plastic discrete beam material with 6 decoupled DOFs with an optional preload.

Format

(1) (2) (3) (4) (5) (6) (7) (8)
*MAT_068 or *MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM
mat_ID ρ i TK_r TK_s TK_t RK_r RK_s RK_t
TD_r TD_s TD_t RD_r RD_s RD_t    
LCPD_r LSPD_s LCPD_t LCPM_r LCPM_s LCPM_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    
FO_r FO_s FO_t MO_r MO_s MO_t    

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer)

ρ i Initial density.

(Real)

[ kg m 3 ]
TK_r, TK_s, TK_t Stiffness in directions r, s, t.

(Real)

[ N m ]
RK_r, RK_s, RK_t Rotational stiffness for axis r, s, t.

(Real)

[ N m rad ]
TD_r, TD_s, TD_t Damping in directions r, s, t.

(Real)

[ N • s m ]
RD_r, RD_s, RD_t Rotational damping in directions r, s, t.

(Real)

[ Nms rad ]
LCPD_r, LCPD_s, LCPD_t Force versus plastic displacement curve identifier in directions r, s, t. 4

(Real)

[ N ]
LCPM_r, LCPM_s, LCPM_t Moment versus plastic rotations curve identifier in directions r, s, t. 4

(Real)

[ Nm ]
FO_r, FO_s, FO_t Force preload in directions r, s, t. [ N ]
MO_r, MO_s, MO_t Moment preload in directions r, s, t. [ Nm ]
FFAIL_r, FFAIL_s, FFAIL_t Failure forces in directions r, s, t. [ N ]
MFAIL_r, MFAIL_s, MFAIL_t Failure moments in directions r, s, t. [ Nm ]
UFAIL_r, UFAIL_s, UFAIL_t Failure elongations in directions r, s, t. [ m ]
TFAIL_r, TFAIL_s, TFAIL_t Failure rotation angles in directions r, s, t. [ rad ]

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 versus displacement and moment versus 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. If for a DOF both force-based and displacement-based failure is defined, then only force failure will be used.
  6. 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.