Engine Subroutine LUSERnnC for Shell Elements
This subroutine calculates the stress tensor versus the strain tensor, strain rate tensor, or user variables.
Arguments
C------------------------------------------------------------------------------
SUBROUTINE LUSERnnC(
1 NEL,NUPARAM,NUVAR,NFUNC,IFUNC,
2 NPF,NGL,TF,TIME,TIMESTEP,
3 UPARAM,RHO0,AREA,EINT,SHF,
4 SOUNDSP,VISCMAX,PLA,UVAR,OFF,
5 SIGY,USERBUF)
C-----------------------------------------------------------------------------
The user’s material law can be used in isotropic mode with PID 1 or in orthotropic mode with PID 9, 10, or 11. The directions XX, YY, ... are the shell local reference frame axis. Stresses are computed at each integration point.
FINTER
to get the value Y of
the function for the abscissa
X.Y=FINTER(IFUNC(I),X,NPF,TF,DYDX)
- Variable
- Description
- Y
- Interpolated value
- X
- Abscissa value of the function
- I
- The ith user’s function
- DYDX
- Slope
- NPF, TF
- Private function parameters
The SOUNDSP
array should always be set by you. It is used to
calculate the stability time step and the hourglass forces. The sound speed value
should be equal to the plane wave speed.
Use VISCMAX
to calculate the time step stability when the material
law formulation is viscous.
Definitions
Argument | Format | Description |
---|---|---|
NEL |
Integer read only scalar | Number of elements per group. In Radioss Engine subroutines, the element data are treated by groups for vectorization. This argument is machine-dependent and set by Radioss. |
NUPARAM |
Integer read only scalar | Size of the user parameter array. |
NUVAR |
Integer read only scalar | Number of user element variables. |
NFUNC |
Integer read only scalar | Number of functions used for material law. |
IFUNC |
Integer array read only | Array of size NFUNC with function
indexes. |
NPF |
Integer array private data | Array used by FINTER (float external
function). |
TF |
Integer array private data | Array used by FINTER (float external
function). |
IPT |
Integer read only scalar | Current layer or interrogation point. |
TIME |
Float read only | Current time. |
TIMESTEP |
Float read only | Current time step. |
UPARAM |
Float array read only | User material parameter array of size
NUPARAM . |
RHO0 |
Float array read only | Array of size NEL with initial
densities. |
AREA |
Float array read only | Array of size NEL with current element
surfaces. |
EINT |
Float array read only | Array of size 2*NEL with internal membrane and
bending energy. |
SOUNDSP |
Float array write only | Array of size NEL containing sound
speed. |
VISCMAX |
Float array write only | Array of size NEL containing the maximum
damping modulus. |
PLA |
Float array read write | Array of size NEL containing plastic
strain. |
UVAR |
Float array read write | Array of size NEL *NUVAR
containing user element variables. |
OFF |
Float array read write | Array of size NEL containing deleted element
flags.
|
NGL |
Integer array read only | Array of size NEL containing the external
element number. |
SIGY |
Float array read write | Array of size NEL containing yield
stress. |
USERBUF |
Data structure read writer | Defined in LAW_USERSH.mod. This module
should be used to relink the executable inside
LUSERnnC . |
USERBUF
module contains:
Argument | Format | Description |
---|---|---|
NCYCLE |
Integer read only scalar | Current cycle. |
ID |
Integer read only scalar | User material ID. |
ILAYER |
Integer read only scalar | Current cycle. |
IPG |
Integer read only scalar | GAUSS Integration point (surface). |
NPTA |
Integer read only scalar | Number of layers or integration points. |
IFLAG |
Integer array read only scalar | Array of size NEL containing geometric
flags. |
FPSXX , FPSYY ,
FPSZZ , FPSXY ,
FPSYX |
Float array read only | Array of size NEL containing the deformation
gradient tensor. |
R11 , R12 ,
R13 , R21 ,
R22 , R23 ,
R31 , R32 ,
R33 |
Float arrays read only | Array of size NEL containing rotation
matrices from the global skew system to an element skew
system. |
THKLYL |
Float array read only | Array of size NEL containing the layer
thickness at each integration point. |
THKN |
Float array read write | Array of size NEL containing total
thickness. |
EPSPXX , EPSPYY ,
EPSPXY , EPSPYZ ,
EPSPZX |
Float array read only | Arrays of size NEL containing
strain rates in directions XX and YY
and strains in directions XY, YZ, and ZX.
|
DEPSXX , DEPSYY ,
DEPSXY , DEPSYZ ,
DEPSZX |
Float array read only | Arrays of size NEL containing
strain increments in directions XX and
YY and strain increments in directions XY, YZ,
and ZX. |
EPSXX , EPSYY ,
EPSXY , EPSYZ ,
EPSZX |
Float array read only | Array of size NEL containing
strains in directions XX and YY and
strains in directions XY, YZ, and
ZX. |
SIGOXX , SIGOYY ,
SIGOZZ , SIGOXY ,
SIGOYZ , SIGOZX |
Float array read only | Array of size NEL containing old (previous
time step) elastoplastic stresses in directions XX, YY, ZZ, XY,
YZ, and ZX. |
SIGNXX , SIGNYY ,
SIGNXY , SIGNYZ ,
SIGNZX |
Float array write only | Array of size NEL containing new computed
elastoplastic stresses in directions XX, YY, XY, YZ, and ZX.
|
SIGVXX , SIGVYY ,
SIGVZZ , SIGVXY ,
SIGVYZ , SIGVZX |
Float array write only | Array of size NEL containing viscous
stresses in directions XX, YY, XY, YZ, and ZX. |
DPLA |
Float array write only | Array of size NEL containing the plastic
strain. |
ETSE |
Float array write only | Array of size NEL containing Et/E (tangent
modulus divided by Young’s modulus). |
TEMP |
Float array read only | Array of size NEL containing the
temperature. |
Shell Element Law Output
Unlike solid elements, shell elements do not have any variables specific to user’s law that are saved in time-history and animation.
Data Necessary for QEPH Compatibility
The Yield value and value Et/E (tangent modulus divided by Young's modulus) must be given in order for this law to be compatible with QEPH element. The prototype of this routine and the necessary data to provide are described in User's Material Law for Shell Elements Example.