/PROP/TYPE28 (NSTRAND)

Block Format Keyword Describes the multi-strand property set.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/PROP/TYPE28/prop_ID/unit_ID or /PROP/NSTRAND/prop_ID/unit_ID
prop_title
Mass K C        
fct_ID1 fct_ID2 εmin εmax Y_SCAL X_SCAL
μ i μ 2            
Specific friction coefficient for pulleys or strands 9 10
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
Type k μ            

Definition

Field Contents SI Unit Example
prop_ID Property identifier

(Integer, maximum 10 digits)

 
unit_ID Unit Identifier

(Integer, maximum 10 digits)

 
prop_title Property title

(Character, maximum 100 characters)

 
Mass Mass per unit length

(Real)

[ kg m ]
K Stiffness for a length of a unitary length

(Real)

[ N ]
C Damping coefficient of a unitary length

(Real)

[ Ns ]
fct_ID1 Function identifier defining F = f ( ε )

(Integer)

 
fct_ID2 Function identifier defining G = f ( ε ˙ )

(Integer)

 
ε min Compression failure strain

Default = -1030 (Real)

 
ε max Tension failure strain

Default = 1030 (Real)

 
Y_SCAL Coefficient for the force (homogeneous to a force)

Default = 1.0 (Real)

[ N ]
X_SCAL Coefficient for the strain rate (homogeneous to a force)

Default = 1.0 (Real)

[ 1 s ]
μ 1 Pulley general friction coefficient

(Real)

 
μ 2 Strand general friction coefficient

(Real)

 
Type Keyword "PULLEY" or "STRAND" (left justified)

(Character)

 
k Pulley or strand number (internal node number in the element)

(Integer)

 
μ Friction coefficient at pulley or along strand

(Real)

 

Comments

  1. To define the connectivity of multi-strand elements, refer to /XELEM.
  2. The force in the spring is computed as:
    Linear spring:(1)
    F = K L 0 δ + C L 0 δ ˙
    Nonlinear spring:(2)
    F = f ( ε ) g ( ε ˙ ) + C L 0 δ ˙

    if fct _ I D 1 0 or fct _ I D 2 0

    Where, ε ˙ is the engineering strain:(3)
    ε = δ l L 0

    and L 0 is the reference length of element.

  3. If fct _ I D 1 = 0 ,(4)
    F = g ( ε ˙ ) + C L 0 δ ˙
  4. If fct _ I D 2 = 0 ,(5)
    F = f ( ε ) + C L 0 δ ˙
  5. Pulley type friction is defined (except at end nodes of the element).

    clip0096
    Figure 1.
    (6)
    | F k 1 F k | ( F k 1 + F k ) tanh ( β μ 2 )
  6. F k 1 is the force in strand connecting nodes Nk-1 and Nk.
  7. Fk is the force in strand connecting nodes Nk and Nk+1.
  8. You can also define friction along strands.
  9. Specific friction coefficients is defined (different from general values) for some pulleys or for some strands (Line 6).
  10. If n is the total number of nodes of an element, strands are numbered from one to (n) and all pulleys (internal nodes) are numbered from 2 to (n-1).