/PROP/TYPE35 (STITCH)
Block Format Keyword This property describes the stitch spring. The stitch spring is characterized by complex parameterizable failure criteria, which differ in compression and tension.
If maximum deformation is greater than a failure criteria in a given direction, the spring enters a damaged mode. The mode information is transmitted to neighboring spring elements which will begin to fail. The property type STITCH must be used with spring elements.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/PROP/TYPE35/prop_ID/unit_ID or /PROP/STITCH/prop_ID/unit_ID | |||||||||
prop_title | |||||||||
Amas | Elastif | Xlim1 | Xk | ||||||
fct_ID1 | fct_ID2 | fct_ID3 | fct_ID4 | Damg | Fdelay |
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) |
|
Amas | Mass per unit
length. (Real) |
|
Elastif | Stiffness per unit
length. (Real) |
|
Xlim1 | Tension transition
deformation. (Real) |
|
Xk | Stiffness for
interface. (Real) |
|
fct_ID1 | Initial tension function
identifier. (Integer) |
|
fct_ID2 | Initial compression
function identifier. (Integer) |
|
fct_ID3 | Final tension function
identifier. (Integer) |
|
fct_ID4 | Final compression function
identifier. (Integer) |
|
Damg | Damage factor 0 <
Damg < 1. 4
(Real) |
|
Fdelay | Failure delay
factor. (Real) |
Comments
- There are two models defined in the
property.First model before damage with the following inputs:
- Elastif
- fct_ID1 defines yield force versus strain in case of tension
- fct_ID2 defines yield force versus strain in case of compression
Second model after damage with the following inputs:- Elastif
- fct_ID3 defines yield force versus strain in case of tension
- fct_ID4 defines yield force versus strain in case of compression
- There are no default values for this property, all parameters should be defined.
- The damage begins when:
- The spring reaches its strain tension limit Xlim1; or
- A connected spring reaches its own strain tension limit.
- Damg is
used only after n=1/Fdelay
cycles:
- Damg = 0 the spring remains on fct_ID3 and fct_ID4
- Damg = 1 the internal force is reset to zero within one cycle
This coefficient was introduced to improve stability when the internal forces are set to 0.0, due to failure.
A value of 0.8 is recommended.