/PROP/TYPE26 (SPR_TAB)
Block Format Keyword Defines the tabulated spring property.
Format
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

/PROP/TYPE26/prop_ID/unit_ID or /PROP/SPR_TAB/prop_ID/unit_ID  
prop_title  
M  sens_ID  I_{sflag}  I_{leng}  Dmin  
Nfunc  Nfund  Lscale  Kmax  Dmax  Alpha 
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

fct_ID_{1}  Fscale  Strain_rate 
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

fct_ID_{1}  Fscale  Strain_rate 
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) 

M  Mass. 2 (Real) 
$\left[\text{kg}\right]$ 
sens_ID  Sensor
identifier. (Integer) 

I_{sflag}  Sensor flag. 3
(Integer) 

I_{leng}  Input per unit length
flag. 2
(Integer) 

Dmin  Failure displacement in
compression. 7 Default = 10^{20} (Real) 
$\left[\text{m}\right]$ 
Nfunc  Numbers of loading
curves. (Integer) 

Nfund  Numbers of unloading
curves. (Integer) 

Lscale  Scale factor for abscissa
of loading and unloading functions depending on flag I_{leng}. 6 Default = 1 (Real) 
$\left[\text{m}\right]$ 
Kmax  Maximum
stiffness. (Real) 
$\left[\frac{\text{N}}{\text{m}}\right]$ 
Dmax  Failure displacement in
tension. 7 Default = 10^{20} (Real) 
$\left[\text{m}\right]$ 
Alpha  Strain rate filtering
factor. Values between 0.0 and 1.0. Default value = 1.0 (no strain filtering) (Real) 

fct_ID_{1}  Function identifier
defining f(
$\delta $
) or f(
$\text{\epsilon}$
) depending on flag I_{leng}. (Integer) 

Fscale  Scale factor for loading
and unloading functions. (Real) 
$\left[\text{N}\right]$ 
Strain_rate  Displacement or strain
rate depending on I_{leng} which corresponds to a loading or unloading
function. (Real) 
$\left[\frac{\text{m}}{\text{s}}\right]$ 
Comments
 Let $\delta $ = L  ${L}_{0}$ be the difference between the current length and the initial length ${L}_{0}$ of the spring element.
 If I_{leng}=1, the spring properties are based on the reference
spring length. The input should be entered as:
$M=\frac{m}{{l}_{0}}$ $K=k*{l}_{0}$ Each spring will then have the following properties in the model:Where,$m=M\cdot {l}_{0}$ $k=\frac{K}{{l}_{0}}$  $M$ and $K$
 Spring values entered in the spring property fields
 $m$ and $k$
 Spring’s actual physical mass, stiffness and damping
 ${l}_{0}$
 Initial spring length which is the distance between node N1 and N2 of the spring
 Dmin and Dmax
 Entered as engineering strain
 Strain_rate
 Entered as engineering strain rate
 Spring is activated
and/or deactivated by sensor defined in sens_ID and depends on I_{sflag}:
 If I_{sflag} = 0, the spring element is activated by the sens_ID and cannot be deactivated. The initial length of the spring is based on the spring length at time=0.
 If I_{sflag} = 1, the spring element is deactivated by the sens_ID and cannot be activated. The initial length of the spring is based on the spring length at time=0.
 If I_{sflag} = 2, the spring is activated and/or deactivated by sens_ID and can switch activation state multiple times. If sensor is activated, the spring is active; if sensor is deactivated, spring is deactivated. The spring initial length, ${l}_{0}$ , is the distance between spring nodes at the time of sensor activation.
 Force calculations:
 If I_{leng} =0, the force is defined as a function of
displacement:
(1) $$F=\mathrm{f}(\delta ,\dot{\delta})$$  If I_{leng} =1, the force is defined as a function of
strain:
(2) $$F=\mathrm{f}(\epsilon ,\dot{\epsilon})$$
Where, $\text{\epsilon}$
 Engineering strain.
 ${L}_{0}$
 Reference length of the element, with ${L}_{0}<\delta <\infty $
 If I_{leng} =0, the force is defined as a function of
displacement:
 Spring forces are
calculated using loading and unloading functions for different rates.
 The 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.
 Lscale is used only when the I_{leng} =0 (abscissa unit is length); otherwise the default value =
1.
(3) $$F=Fscale\cdot {\mathrm{f}}_{1}\left(\frac{L}{Lscale}\right)$$Where, ${\mathrm{f}}_{1}$ is the function of fct_ID_{1}.
 The failure of the
spring is triggered by two displacement values, one negative value for
compressive loadings Dmin and one positive value for tensile
loadings Dmax. Thus, failure occurs when:
(4) $$\begin{array}{ccc}\delta \le \leftDmin\right& or& \delta \ge \leftDmax\right\end{array}$$