/PROP/TYPE4 (SPRING)

Block Format Keyword

/PROP/TYPE4 - Spring Property Set

Description

Defines spring property with one translational DOF. This spring accounts for non-linear stiffness, damping and different unloading. Deformation based failure criteria is available.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/PROP/TYPE4/prop_ID/unit_ID or /PROP/SPRING/prop_ID/unit_ID
prop_title
Mass					sens_ID	Isflag	Ileng
K1		C1		A1		B1		D1
fct_ID11	H1	fct_ID21	fct_ID31	fct_ID41
F1		E1		Ascale1		Hscale1

Field	Contents	SI Unit Example
prop_ID	Property identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
prop_title	Property title (Character, maximum 100 characters)
Mass	Mass or depending on flag Ileng (Comments 2 and 3) (Real)	or
sens_ID	Sensor identifier (Integer)
Isflag	Sensor flag (Comment 8) (Integer) =0: spring element activated =1: spring element deactivated =2: spring element activated or deactivated
Ileng	Input per unit length flag (Integer) = 0: force in the spring is computed (Comment 2) = 1: all input are per unit length (Comment 3)
K1	For linear spring: Stiffness or Stiffness multiply l0 depending on flag Ileng For elasto-plastic spring: Unloading stiffness or Unloading stiffness multiply l0 depending on flag Ileng (Comments 2 and 3) (Real)	or
C1	Damping or Damping multiply l0 for tension depending on flag Ileng (Comments 2 and 3) (Real)	or
A1	Coefficient for strain rate effect in tension (homogeneous to a force) Default = 1.0 (Real)
B1	Logarithmic coefficient for strain rate effect in tension (homogeneous to a force) (Real)
D1	Scale coefficients for tension velocity Default = 1.0 (Real)
fct_ID11	Function identifier defining or depending on flag Ileng If H1 =4: Function identifier defining upper yield curve If H1 =8: Function identifier defining force vs spring length (Comments 2 and 3) (Integer) = 0: linear spring
H1	Hardening flag (Integer) = 0: Nonlinear elastic spring = 1: Nonlinear elastic plastic spring = 2: Nonlinear elasto-plastic spring with decoupled hardening in tension and compression = 4: Nonlinear elastic plastic spring “kinematic” hardening = 5: Nonlinear elasto-plastic spring with nonlinear unloading = 6: Nonlinear elasto-plastic spring with isotropic hardening and nonlinear unloading = 7: Nonlinear spring with elastic hystersis = 8: Nonlinear spring with elastic total length function
fct_ID21	Function identifier defining or depending on flag Ileng (Comments 2 and 3) (Integer)
fct_ID31	Function used only for unloading If H1 =4: Function identifier defining lower yield curve If H1 =5: Function identifier defining residual displacement vs maximum displacement (Integer)
fct_ID41	Function identifier defining (Integer)
	Negative failure displacement or Negative failure displacement multiply l0 depending on flag Ileng (Comments 2 and 3) Default = -1030 (Real)
	Positive failure displacement or Positive failure displacement multiply l0 depending on flag Ileng (Comments 2 and 3) Default = 1030 (Real)
F1	Scale factor for or (abscissa of or function) (Real)
E1	Coefficient for strain rate effect (homogeneous to a force) (Real)
Ascale1	Coefficient for or (abscissa of or function) (Real)
Hscale1	Coefficient for fct_ID41 (homogeneous to a force) Default = 1 (Real)

(Seatbelt)

#RADIOSS STARTER

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/UNIT/2

unit for prop

kg mm ms

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/PROP/SPRING/2/2

Seatbelt

# M sens_ID Isflag Ileng

5E-5 0 0 1

# K1 C1 A1 B1 D1

0.001 0 0 0 0

# fct_ID11 H1 fct_ID21 fct_ID31 fct_ID41 delta_min delta_max

1 2 0 0 0 0

# F1 E1 Ascale1 Hscale1

0 0 0 0

/MOVE_FUNCT/1

Seatbelt

# Ascale_x Fscale_y Ashift_x Fshift_y

0.001

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/FUNCT/1

Seatbelt loading force vs engineering strain

# X Y

0. 0.

0.005 700.

0.02 3100.

0.03 5500.

0.15 17000.

1000. 17000.

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#ENDDATA

1.	The spring’s X direction is defined using nodes N1 and N2 of the spring.

If the node of the spring N3 is defined, the spring’s Y’ direction is defined using nodes N1 and N3 of the spring. N3, N2, and N1 should not be in a line.

•	The Z direction is:

•	If node N3 is not defined in the element input, and skew system is defined in the property input, the Z direction is:

•	If neither node N3 nor skew system are defined in input, the Z direction is:

prop_spr_beam14

Finally, Y direction is found as:

•	Local skew system follows motion of N1.

2.	If Ileng =0, the value of force F in the spring is computed as:

Linear spring:

Nonlinear spring (except, H1 = 8):

with

Nonlinear spring - H1 = 8:

with and

linear_spring

Linear spring

nonlinear_spring_0

Nonlinear elastic spring, H1=0

nonlinear_spring_1

Nonlinear elastic plastic spring, H1=1

nonlinear_spring_2

Nonlinear elastic plastic spring with decoupled hardening in tension and compression, H1=2

nonlinear_spring_4

Nonlinear elastic plastic spring "kinematic" hardening, H1=4

nonlinear_spring_5

Nonlinear elastic plastic spring with nonlinear unloading, H1=5

nonlinear_spring_6

Nonlinear elasto-plastic spring with isotropic hardening and nonlinear unloading, H1=6

nonlinear_spring_7

Nonlinear spring with elastic hysteresis, H1=7

nonlinear_spring_8

Nonlinear spring with elastic total length function, H1=8

3.	If Ileng = 1, all input are per unit length:

•	Spring mass = Spring stiffness = Spring damping = Spring inertia =

Where, l0 is the reference spring length.

•	The value of force F in the spring is computed as:

- Linear spring:

- Nonlinear spring:

where, is the engineering strain:

- Force functions are given versus engineering strain and engineering strain rate.

- Failure criteria are defined with respect to strain. Input negative/positive failure limit should be related to initial length l0

4.	For H1 > 0, if fct_ID11 = 0, function or is assumed to be constant, equal to 1. For H1 =8, fct_ID1 is mandatory.

5.	If (or ) is 0, then there will be no failure in the negative direction (or positive).

If hardening flag H1 is 4, the loading curve should be positive for all values of abscissa. The unloading curve in this case should be negative for all values of abscissa. For flag 4, these curves represents upper and lower limits of yield force as function of current spring length variation or strain. The force jumps between the curves each time when the direction of deformation changes.

7.	If hardening flag H1 is 5, residual deformation is a function of maximum displacement:

8.	Spring activated and/or deactivated by sensor:

•	If sens_ID ≠ 0 and Isflag = 0, the spring element is activated by the sens_ID.

•	If sens_ID ≠ 0 and Isflag = 1, the spring element is deactivated by the sens_ID.

•	If sens_ID ≠ 0 and Isflag = 2, then:

o	The spring is activated and/or deactivated by sens_ID (if sensor is ON, spring is ON; if sensor is OFF, spring is OFF).

o	The spring reference length (l0) is the distance between the two extremities at sensor’s activation.

If a sensor is used for activating or deactivating a spring, the reference length of the spring at sensor activation (or deactivation) is equal to the nodal distance at time =0; except if sensor flag is equal to 2.

/PROP/TYPE4 (SPRING)

/PROP/TYPE4 (SPRING)

/PROP/TYPE4 (SPRING)

See Also: