/MAT/LAW90
Block Format Keyword This law describes the visco-elastic foam tabulated material. This material law can be used only with solid elements.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/MAT/LAW90/mat_ID/unit_ID | |||||||||
mat_title | |||||||||
E0 | |||||||||
NL | Ismooth | Fcut | Shape | Hys |
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
fct_IDL | FscaleL |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
mat_ID | Material identifier (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier (Integer, maximum 10 digits) |
|
mat_title | Material title (Character, maximum 100 characters) |
|
Initial density (Real) |
||
E0 | Initial Young's modulus. 2 (Real) |
|
Poisson's ratio. (Real) |
||
Ismooth | Smooth strain rate option flag.
(Integer) |
|
Fcut | Cutoff frequency for strain rate
filtering. Default = 1030 (Real) |
|
NL | Number of loading
functions. (Integer) |
|
fct_IDL | Load function (in compression)
identifier. (Integer) |
|
Strain rate for load
function. (Real) |
||
FscaleL | Load function scale
factor. (Real) |
|
Shape | Shape factor. Default = 1.0 (Real) |
|
Hys | Hysteresis unloading factor. Default = 1.0 (Real) |
Example
#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
kg mm ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 2. MATERIALS:
/MAT/LAW90/1/1
foam
# RHO_I
3E-8
# EO NU
0.01 0
# Nload Ismooth F_cut Shape Hys
3 1 10 10. 0.15
# fct_IDL Eps_._load Fscaleload
12 .1 0
13 1 0
13 100 0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 3. FUNCTIONS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/12
NULL
# X Y
-0.300 -0.546
-0.200 -0.534
-0.100 -0.398
0.000 0.000
0.010 0.065
0.020 0.105
0.030 0.123
0.040 0.129
0.050 0.134
0.060 0.138
0.070 0.142
0.080 0.145
0.090 0.150
0.100 0.153
0.200 0.183
0.300 0.211
0.400 0.243
0.500 0.287
0.600 0.356
0.700 0.489
0.800 0.828
0.900 2.434
0.950 11.978
0.960 24.042
0.970 74.879
0.980 460.893
0.99 12810.97
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/13
NULL
# X Y
-0.300 -0.546
-0.200 -0.534
-0.100 -0.398
0.000 0.000
0.010 0.065
0.020 0.105
0.030 0.123
0.040 0.129
0.050 0.134
0.060 0.138
0.070 0.142
0.080 0.145
0.090 0.150
0.100 0.153
0.200 0.183
0.300 0.211
0.400 0.243
0.500 0.287
0.600 0.356
0.700 0.489
0.800 0.828
0.900 2.434
0.950 11.978
0.960 24.042
0.970 74.879
0.980 460.893
0.99 12810.97
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
Comments
- Control of the unloading response: There are
two ways for controlling the unloading:
- If Hys=0, follow the quasi-static loading curve for unloading.
- If Hys
> 0, the loading curve are used for both loading and unloading behavior and the tensor
unloading tensor stress is reduced by:
(1) With(2) Where, and are current and maximum quasi-static energy.
- For stresses above the last load function, the behavior is extrapolated by using the two last load functions. Then, in order to avoid huge stress values, it is recommended to repeat the last load function.
- The loading curve should be defined as:
- Positive abscissa and ordinate for the compression
- Negative abscissa and ordinate for traction (tension)
- In order to recover the stress
and strain using initial state file, the following options have to be saved in ASCII Output File (STY-File):
- /OUTP/STRESS/FULL
- /OUTP/STRAIN/FULL
- /OUTP/USERS/FULL
- Specific material output
variables:
- USR2: Maximum for quasi-static energy
- USR3: Strain rate in principal direction 1
- USR4: Strain rate in principal direction 2
- USR5: Strain rate in principal direction 3
- /VISC/PRONY can be used with this material law to include viscous effects.