/PROP/TYPE8 (SPR

Block Format Keyword

/PROP/TYPE8 - General Spring Property Set

Description

This spring property works with six independent modes of deformation. This spring accounts for non-linear stiffness, damping and different unloading. Deformation, force and energy based failure criteria are available. The general spring property is often used to model a joint connection between two parts.

Format

(1)	(3)	(5)	(6)	(7)	(8)	(10)
/PROP/TYPE8/prop_ID/unit_ID or /PROP/SPR_GENE/prop_ID/unit_ID
prop_title
Mass	I	skew_ID	sens_ID	Isflag	Ifail	Iequil

Translation in X

K1		C1		A1		B1	D1
fct_ID11	H1	fct_ID21	fct_ID31	fct_ID41
F1		E1		Ascale1		Hscale1

Translation in Y

K2		C2		A2		B2	D2
fct_ID12	H2	fct_ID22	fct_ID32	fct_ID42
F2		E2		Ascale2		Hscale2

Translation in Z

K3		C3		A3		B3	D3
fct_ID13	H3	fct_ID23	fct_ID33	fct_ID43
F3		E3		Ascale3		Hscale3

Rotation in X

K4		C4		A4		B4	D4
fct_ID14	H4	fct_ID24	fct_ID34	fct_ID44
F4		E4		Ascale4		Hscale4

Rotation in Y

(1)	(2)	(3)	(4)	(5)	(7)	(9)
K5		C5		A5	B5	D5
fct_ID15	H5	fct_ID25	fct_ID35	fct_ID45
F5		E5		Ascale5	Hscale5

Rotation in Z

K6		C6		A6		B6	D6
fct_ID16	H6	fct_ID26	fct_ID36	fct_ID46
F6		E6		Ascale6		Hscale6

Filtering forces

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
Israte	Asrate

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 (Real)
I	Inertia (Real)
skew_ID	Skew system identifier. If not defined, then global coordinate system is used. (Integer)
sens_ID	Sensor identifier (Integer)
Isflag	Sensor flag (Comment 12) (Integer) = 0: spring element activated = 1: spring element deactivated = 2: spring element activated or deactivated
Ifail	Failure criteria (Integer) = 0: uni-directional criteria = 1: multi-directional criteria
Iequil	Equilibrium flag (Comment 2) (Integer) = 0: no equilibrium = 1: force and moment equilibrium
K1	Transitional stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) (Comment 6) (Real)
C1	Transitional damping for translation in X (Real)
A1	Coefficient in strain rate effect in direction X (homogeneous to a force) Default = 1.0 (Real)
B1	Logarithmic coefficient in strain rate effect in direction X (homogeneous to a force) (Real)
D1	Scale coefficients for translational velocity in X Default = 1.0 (Real)
fct_ID11	Function identifier defining transition in X If H1 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H1	Transitional 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 hysteresis
fct_ID21	Function identifier defining transition in X (Integer)
fct_ID31	Function used only for unloading for translation in X If H1 = 4: Function identifier defining lower yield curve (transitional) If H1 = 5: Function identifier defining residual displacement vs maximum displacement If H1 = 7: Function identifier unloading curve for force vs displacement (relative displacement) (Integer)
fct_ID41	Function identifier defining for translation in X (Integer)
	Negative failure displacement, transitional Default = -1030 (Real)
	Positive failure displacement, transitional Default = 1030 (Real)
F1	Scale factor for , transitional for translation in X (Real)
E1	Coefficient for strain rate effect in direction X (homogeneous to a force) (Real)
Ascale1	Abscissa scale factor for (fct_ID11 and fct_ID13) (Real)
Hscale1	Coefficient for fct_ID41 used for translation in X (homogeneous to a force) Default = 1 (Real)
K2	Transitional stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) for translation in Y (Real)
C2	Transitional damping for translation in Y (Real)
A2	Coefficient for strain rate effect in direction Y (homogeneous to a force) Default = 1.0 (Real)
B2	Logarithmic coefficient for strain rate effect in direction Y (homogeneous to a force) (Real)
D2	Scale coefficients for translation velocity in Y Default = 1.0 (Real)
fct_ID12	Function identifier defining transition in Y If H2 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H2	Transitional 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 hysteresis
fct_ID22	Function identifier defining transition in Y (Integer)
fct_ID32	Function used only for unloading for translation in Y If H2 = 4: Function identifier defining lower yield curve (transitional) If H2 = 5: Function identifier defining residual displacement vs maximum displacement If H2 = 7: Function identifier unloading curve for force vs displacement (relative displacement) (Integer)
fct_ID42	Function identifier defining for translation in Y (Integer)
	Negative failure displacement, transitional Default = -1030 (Real)
	Positive failure displacement, transitional Default = 1030 (Real)
F2	Scale factor for , transitional in translation in Y (Real)
E2	Coefficient for strain rate effect in direction Y (homogeneous to a force) (Real)
Ascale2	Abscissa scale factor for (fct_ID12 and fct_ID32) for translation in Y (Real)
Hscale2	Coefficient for fct_ID42 for translation in Y (homogeneous to a force) Default = 1 (Real)
K3	Transitional stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) for translation in Z (Real)
C3	Transitional damping (Real)
A3	Coefficient for strain rate effect in direction Z (homogeneous to a force) Default = 1.0 (Real)
B3	Logarithmic coefficient for strain rate effect in direction Z (homogeneous to a force) (Real)
D3	Scale coefficient for translation velocity in direction Z Default = 1.0 (Real)
fct_ID13	Function identifier defining transitional in Z If H3 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H3	Transitional 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 hysteresis
fct_ID23	Function identifier defining transition in Z (Integer)
fct_ID33	Function used only for unloading for translation in Z If H3 = 4: Function identifier defining lower yield curve (transitional) If H3 = 5: Function identifier defining residual displacement vs maximum displacement If H3 = 7: Function identifier unloading curve for force vs displacement (relative displacement) (Integer)
fct_ID43	Function identifier defining for translation in Z (Integer)
	Negative failure displacement, transitional Default = -1030 (Real)
	Positive failure displacement, transitional Default = 1030 (Real)
F3	Scale factor for , transitional for translation in Z (Real)
E3	Coefficient for strain rate effect in direction Z (homogeneous to a force) (Real)
Ascale3	Abscissa scale factor for (fct_ID13 and fct_ID33) (Real)
Hscale3	Coefficient for fct_ID43 for translation in Z (homogeneous to a force) Default = 1 (Real)
K4	Rotational stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) for torsion in X (Real)
C4	Rotational damping for torsion in X (Real)
A4	Coefficient for strain rate effect torsion in X (homogeneous to a moment) Default = 1.0 (Real)
B4	Logarithmic coefficient for strain rate effect in torsion X (homogeneous to a moment) (Real)
D4	Scale coefficients for torsion velocity in X Default = 1.0 (Real)
fct_ID14	Function identifier defining , rotational for torsion in X If H4 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H4	Rotational 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 hysteresis
fct_ID24	Function identifier defining , rotational for torsion in X (Integer)
fct_ID34	Function used only for unloading for torsion in X If H4 = 4: Function identifier defining lower yield curve, rotational If H4 = 5: Function identifier defining residual displacement vs maximum displacement If H4 = 7: Function identifier defining unloading curve of moment vs rotation (Integer)
fct_ID44	Function identifier defining for torsion in X (Integer)
	Negative failure rotation Default = -1030 (Real)
	Positive failure rotation Default = 1030 (Real)
F4	Scale factor for , rotational for torsion in X (Real)
E4	Coefficient for strain rate effect for torsion in X (homogeneous to a moment) (Real)
Ascale4	Abscissa scale factor for for torsion in X (fct_ID14 and fct_ID34) (Real)
Hscale4	Coefficient for fct_ID44 for torsion in X (homogeneous to a force) Default = 1 (Real)
K5	Rotational stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) for rotation in Y (Real)
C5	Rotational damping for rotation in Y (Real)
A5	Coefficient for strain rate effect, rotation in Y (homogeneous to a moment) Default = 1.0 (Real)
B5	Logarithmic coefficient for strain rate effect, rotation in Y (homogeneous to a moment) (Real)
D5	Scale coefficients for rotation velocity in Y Default = 1.0 (Real)
fct_ID15	Function identifier defining , rotational for torsion in Y If H5 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H5	Rotational 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 hysteresis
fct_ID25	Function identifier defining , rotation for in Y (Integer)
fct_ID35	Function used only for unloading for rotation in Y If H5 = 4: Function identifier defining lower yield curve, rotational If H5 = 5: Function identifier defining residual rotation vs maximum rotation If H5 = 7: Function identifier defining unloading curve for moment vs rotation (Integer)
fct_ID45	Function identifier defining for rotation in Y (Integer)
	Negative failure rotation Default = -1030 (Real)
	Positive failure rotation Default = 1030 (Real)
F5	Scale factor for , rotational for rotation in Y (Real)
E5	Coefficient for strain rate effect in rotation in Y (homogeneous to a moment) (Real)
Ascale5	Abscissa scale factor for for rotation in Y (fct_ID15 and fct_ID35) (Real)
Hscale5	Coefficient for fct_ID45 for rotation in Y (homogeneous to a force) Default = 1 (Real)
K6	Rotational stiffness (for linear spring) or unloading stiffness (for elasto-plastic spring) for rotation in Z (Real)
C6	Rotational damping for rotation in Z (Real)
A6	Coefficient for strain rate effect, rotation Z (homogeneous to a moment) Default = 1.0 (Real)
B6	Logarithmic coefficient for strain rate effect, rotation in Z (homogeneous to a moment) (Real)
D6	Scale coefficients for rotation in Z Default = 1.0 (Real)
fct_ID16	Function identifier defining , rotation in Z If H6 = 4: Function identifier defining upper yield curve (Integer) = 0: linear spring
H6	Rotational 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 hysteresis
fct_ID26	Function identifier defining , rotation in Z (Integer)
fct_ID36	Function used only for unloading for rotation in Z If H6 = 4: Function identifier defining lower yield curve, rotational If H6 = 5: Function identifier defining residual rotation vs maximum rotation If H6 = 7: Function identifier defining unloading curve for moment vs rotation (Integer)
fct_ID46	Function identifier defining for rotation in Z (Integer)
	Negative failure rotation Default = -1030 (Real)
	Positive failure rotation Default = 1030 (Real)
F6	Scale factor for , rotational for rotation in Z (Real)
E6	Coefficient for strain rate effect rotation in Z (homogeneous to a moment) (Real)
Ascale6	Abscissa scale factor for for rotation in Z (fct_ID16 and fct_ID36) (Real)
Hscale6	Coefficient for fct_ID46 for rotation in Z (homogeneous to a force) Default = 1 (Real)
Israte	Smooth strain rate flag (Integer)
Asrate	Strain rate cutting frequency (Real)

1.	The spring has six DOF computed in a skew system frame:

clip0116

•	The six DOF are independent. If initial length is not equal to zero, the equilibrium is insured for forces, but not for moments. It is then recommended to use spring elements type 8 with a zero length or with one of the two nodes fixed in all directions.

•	If is a translational DOF, the force in direction is computed as:

Linear spring:

for i= 1, 2, 3

Nonlinear spring:

for i= 1, 2, 3

•	If is a rotational DOF, the moment is computed as:

Linear spring:

for i= 4, 5, 6

Nonlinear spring:

for i= 4, 5, 6

linear_spring

Linear spring

nonlinear_spring_0

Nonlinear elastic spring, Hi=0

nonlinear_spring_1

Nonlinear elastic plastic spring, Hi=1

nonlinear_spring_2

Nonlinear elasto- plastic spring with decoupled hardening in tension and compression, Hi= 2

nonlinear_spring_4

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

nonlinear_spring_5

Nonlinear elastic plastic spring "kinematic" hardenging, Hi= 5

nonlinear_spring_6

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

With i=1, 2, 3, 4, 5, 6

nonlinear_spring_7

Nonlinear spring with elastic hysteresis, Hi=7

2.	If Iequil = 0, then:

is moment in Y by N2

is moment in Y by N1

3.	If Iequil = 1, then:

is moment in Y by N2

is moment in Y by N1

is moment in Z by N2

is moment in Z by N1

4.	Failure criterion:

•	If the failure criterion is uni-directional, the spring fails as soon as one of the criteria is met in one direction.

•	If the failure criteria is multi-directional, the spring fails if the following relation is true:

with being the failure displacement in direction i= 1, 2, 3

•	If (resp , with i=1, 2, 3) is 0, no failure in the negative direction (resp positive).

5.	For each direction, (with i=1, 2, 3) is taken if is negative, otherwise, is taken if is positive. The (with i=1, 2, 3) must be negative. Both (with i=4, 5, 6) and are expressed in radians.

6.	If Ki (with i=1, 2, 3) is less than the maximum slope of the yield curve (Ki is not consistent with the maximum slope of yield curve), Ki is set to the maximum slope of the curve.

If Ki (with i=4, 5, 6) is less than the maximum slope of the yield curve (Ki is not consistent with the maximum slope of yield curve), Ki is set to the maximum slope of the curve.

If hardening flag Hi 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.

8.	If hardening flag Hi is 5, residual deformation is a function of maximum displacement:

with i=1, 2, 3

with i=4, 5, 6

9.	For linear springs, and (or and ) are null functions and Ai, Bi, and Ei, are not taken into account.

10.	The third node in element definition is not used to determine local coordinate system of the spring. The local coordinate system is determined either by setting a skew or by using global coordinate system, when the skew is not given.

11.

Spring is in compression in a given direction of local coordinate system, when projection of direction from initial position of node N1 to current position of node N1 to the direction of the local coordinate system is positive. Otherwise, the spring is in tension in corresponding direction of local coordinate system.

12.	Spring is 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 sensor 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 node N1 and N2 at the time of sensor 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/TYPE8 (SPR_GENE)

/PROP/TYPE8 (SPR_GENE)

/PROP/TYPE8 (SPR_GENE)

Filtering forces