Block Format Keyword
/PROP/TYPE26 - Tabulated Spring Property Set
Description
Defines the tabulated spring property.
Format
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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(10)
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/PROP/TYPE26/prop_ID/unit_ID or /PROP/SPR_TAB/prop_ID/unit_ID
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prop_title
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M
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sens_ID
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Isflag
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Ileng
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Nfunc
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Nfund
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Lscale
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Kmax
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Alpha
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Loading function cards (Nfunc)
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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(10)
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fct_ID1
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Fscale
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Strain_rate
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Unloading function cards (Nfund)
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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(10)
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fct_ID1
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Fscale
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Strain_rate
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Field
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Contents
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SI Unit Example
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prop_ID
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Property identifier
(Integer, maximum 10 digits)
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unit_ID
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Optional unit identifier
(Integer, maximum 10 digits)
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prop_title
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Property title
(Character, maximum 100 characters)
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M
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Mass or Mass divided by L0 depending on flag Ileng (Comments 6 and 7)
(Real)
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 or 
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sens_ID
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Sensor identifier
(Integer)
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Isflag
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Sensor flag
(Integer)
=0: spring element activated (Comment 2)
=1: spring element deactivated (Comment 3)
=2: spring element activated or deactivated (Comment 4)
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Ileng
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Input per unit length flag
(Integer)
= 0: See Comment 6
= 1: See Comment 7
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Nfunc
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Numbers of loading curves
(Integer)
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Nfund
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Numbers of unloading curves
(Integer)
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Lscale
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Scale factor for abscissa of loading and unloading functions (Comment 9)
Default = 1 (Real)
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Kmax
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Maximum Stiffness or Stiffness multiply with L0 depending on flag Ileng
(Real)
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 or 
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Alpha
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Strain rate filtering factor
Authorized values between 0.0 and 1.0.
Default value = 1.0 (no strain filtering)
(Real)
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fct_ID1
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Function identifier defining  or  depending on flag Ileng (Comments 6 and 7)
(Integer)
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Fscale
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Scale factor for loading and unloading functions
(Real)
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Strain_rate
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 or  corresponding to a loading or unloading function
(Real)
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| 1. | Let  be the difference between the current length and the initial length L0 of the spring element. |
| 2. | If sens_ID ≠ 0 and Isflag = 0, the spring element is activated by the sens_ID. |
| 3. | If sens_ID ≠ 0 and Isflag = 1, the spring element is deactivated by the sens_ID. |
| 4. | If sens_ID ≠ 0 and Isflag = 2, then: |
| • | The spring is activated and/or deactivated by sens_ID
(if sensor is ON, spring is ON; if sensor is OFF, spring is OFF). |
| • | The spring reference length (L0) is the distance between the two extremities at sensor’s activation. |
| 5. | 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. |
| 6. | In case of Ileng =0, the force is computed as  , if Ileng =1 |
The force is 
Where,  is the engineering strain:
and L0 is the reference length of the element, with 
| 7. | If Ileng = 1, all input are per unit length: |
| • | Spring mass =  Spring stiffness = 
Where, L0 is the reference spring length. |
| 8. | Spring forces are calculated using loading and unloading functions for different strain rate. |
| • | Actual strain rate is determined and the maximum loading force as well as the minimum unloading force is determined by interpolation from the input curves. |
| • | The behavior between the loading and unloading curves is linear, using Kmax value as the spring stiffness. |
| • | For both loading and unloading, input curves should be defined in order of strictly increasing strain rate values. |
| • | To describe spring compression behavior, input curves Force(strain) should be strictly positive. |
| • | In traction, spring behavior is linear with stiffness equal to Kmax. |
| 9. | Lscale is used only when the Ileng =1 (abscissa unit is length); otherwise the default value = 1. |
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See Also:
Material Compatibility
/TH/SPRING (Time history output)
/SPRING (Spring element definition)
Spring definition in Model Preparation in User's Guide
