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laws:binds
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BINDS
Description
Constitutive law for BINDS elements.
The model
This law is used to enforce non-linear constraints between several degrees of freedom of the discretized structure.
Files
Prepro: LBINDS.F
Availability
| Plane stress state | YES |
| Plane strain state | YES |
| Axisymmetric state | YES |
| 3D state | YES |
| Generalized plane state | YES |
Input file
Parameters defining the type of constitutive law
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 30 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing |
Integer parameters
| Line 1 (5I5) | |
|---|---|
| LTYP1 | = 1 to enforce elastic constraints = 2 to enforce elasto-plastic constraints = 3 to enforce bi-linear elastic constraints |
| NALPHA | number of different αi coefficients in the constraint equation (including α0) |
| ICODE | = 0 if the constraint equation enforces a rigid body mode = 1 else |
| NDEF | Number of times of definition for α sets |
| IBEND | = 0 generally = 1 if management of bending/unbending thanks to generalized plane strain state |
Real parameters
1. LTYP1 = 1
| Line 1 (7G10.0) - repeated as many times as necessary | |
|---|---|
| ALPHA(I) I = 1,NALPHA | The αi coefficients of the constraint equation |
| Line n=round(NALPHA/7) (G10.0) | |
| TRACE | K1 = the elastic stiffness of the constraint |
2. LTYP1 = 2
| Line 1 (7G10.0) - repeated as many times as necessary | |
|---|---|
| ALPHA(I) I = 1,NALPHA | The αi coefficients of the constraint equation |
| Line n=round(NALPHA/7) (3G10.0) | |
| TRACE(1) | K1 = the elastic stiffness of the constraint |
| TRACE(2) | K2 = the tangent elasto-plastic stiffness of the constraint |
| LH1 | The elastic limit of the constraint |
3. LTYP1 = 3
| Line 1 (7G10.0) - repeated as many times as necessary | |
|---|---|
| ALPHA(I) I = 1,NALPHA | The αi coefficients of the constraint equation |
| Line n=round(NALPHA/7) (2G10.0) | |
| TRACE(1) | K1 = the elastic stiffness in tension |
| TRACE(2) | K2 = the elastic stiffness in compression |
Remarks
- if IBEND = 0 : coefficient α0 is multiplied by DMULT during the simulation
- if IBEND = 1 : in generalised plane strain state, thickness is given by: e(x,y) = A + B.x + C.y
α1 is the coefficient of “A” and it must be equal to the curve in the OXZ plane
α2 is the coefficient of “B” and it must be equal to 1.0
α0 is automatically computed
Stresses
Number of stresses
1
Meaning
| SIG(1) | The generalized force necessary to enforce the constraint. |
State variables
Number of state variables
- 1 if LTYP = 1
- 2 if LTYP = 2
- 1 if LTYP = 3
List of state variables
1. LTYP1 = 1 (elastic constraint)
| Q(1) | = 0 (meaningless) |
| Q(6) | = strain energy |
2. LTYP1 = 2 (elasto-plastic constraint)
| Q(1) | current yield limit ; its initial value is LH1 |
| Q(2) | = 0 if the current state is elastic = 1 if the current state is elasto-plastic. |
| Q(6) | strain energy |
3. LTYP1 = 3 (bi-linear elastic constraint)
| Q(1) | = 0 if the current state is in tension = 1 if the current state is in compression |
laws/binds.txt · Last modified: 2020/08/25 15:46 (external edit)
