Home > List of Keywords > *MAT
*MAT
Data format:
IMAT E NU SG XI X1 X2 X3 XVIV SIGMAB IFLAG_DP ITYP CRITCURV THETA C EIl INL NRP NTP ANL BNL CNL
Status :
Optional
Purpose :
To define material properties for flexible structures
To define the material properties for the VIV calculations
To define non-linear bending behavior law with hysteresis effect parameters for flexible risers
To define non-linear strain-stress relationship for bending stiffener material
Details :
| Parameter | Description |
|---|---|
| IMAT | identification number of the material |
| E | Young's modulus. (if value not present or negative, default value is 2.1e+11N/m2 for *RIGIPRO) |
| NU | Poisson coefficient. (if value not present or negative, default value is 0.3) |
| SG | material specific gravity . (if value not present or negative, default value is 7.85 for *RIGIPRO) |
| XI | damping coefficient if a Rayleigh damping is selected.XI=0. for any other type of damping |
| X1 | damping coefficient for traction and compression mechanism |
| X2 | damping coefficient for flexion mechanism |
| X3 | damping coefficient for torsion mechanism |
| XVIV | structural damping for the VIV calculations |
| SIGMAB | Ultimate failure stress |
| IFLAG_DP | = 0 : Damping coefficients are expressed as beta coefficients = 1 : Damping coefficients are expressed as actual damping rate. |
| ITYP | Default value is 0. = 1 if a non linear bending/curvature law is defined for a flexible pipe |
| CRITCURV | (1/m) critical curvature from which a plastic curvature appears. |
| THETA | (m) First parameter of the hardening rule. Default = 0. |
| C | (Nm2) Second parameter of the hardening rule. Default = 0. |
| EIl | (Nm2) The asymptotic bending stiffness |
| INL | Default value is 0. It is 1 if a non linear thermal dependant law is used. |
| NRP | Number of cells in the radial direction |
| NTP | Number of cells in the angular direction |
| ANL | Coefficient A |
| BNL | Coefficient B |
| CNL | Coefficient C |
Warning
The damping coefficients XI or X1, X2 and X3 used during your dynamic analyses may refer either to beta or actual damping rate ksi coefficients, depending on the IFLAG_DP value. It is important to note that when using a beta type coefficient, the actual damping rate will depend on the motion's period.
The damping coefficient XVIV used within your VIV analyses always corresponds to an actual damping rate ksi. For instance XVIV = 0.01 means the structural damping ratio is 1%.
SIGMAB: Ultimate failure stress. This value is only used by the to obtain a more conservative approach of the fatigue by taking into account the static stress of the structure. The so-called Goodman correction increases the stress range. Defining the static stress as \(\sigma_s\), and the VIV stress range by \(\Delta\sigma_s\), the stress range to be taken into account is:
Note
-
When damping by mechanisms is required XR must be null
-
Default values are steel values without damping
Example :
*MAT
1 -1 -1 -1 0.2
is identical to
*MAT
1 2.1e+11 0.3 7.85 0.2
and represents steel.
