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fct_IDp for Mat LAW 36

Hi,

I'd like to model an elasto-plastic material with a softening and stiffening region. This material behaves differently in compression and tension, thus I would like to input a fct_IDp for Mat LAW 36. Is there an example on how to define this pressure dependent function?

Thanks for the help

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Altair Forum User

Hi @Marie

There is sample table for LAW 36 RADIOSS help. Please check the same:

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
g mm ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/PLAS_TAB/1/1
Aluminium_example
# RHO_I
.0027 0
# E Nu Eps_p_max Eps_t Eps_m
60400 .33 0 0 0
# N_funct F_smooth C_hard F_cut Eps_f VP
14 0 0 0 0 0
# fct_IDp Fscale Fct_IDE EInf CE
0 0 0 0 0
# func_ID1 func_ID2 func_ID3 func_ID4 func_ID5
1 2 3 4 5
6 7 8 9 10
11 12 13 14
# Fscale_1 Fscale_2 Fscale_3 Fscale_4 Fscale_5
1 1.2 1.4 1.6 1.9
10 10.2 10.4 10.6 10.9
20 20.2 20.4 20.6
# Eps_dot_1 Eps_dot_2 Eps_dot_3 Eps_dot_4 Eps_dot_5
0 20 30 40 50
110 120 130 140 150
210 220 230 240
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#- 3. FUNCTIONS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/1
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/2
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/3
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/4
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/5
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/6
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/7
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/8
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/9
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/10
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/11
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/12
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/13
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/14
function_36
# X Y
0 90
2.5E-4 100
.001 104
.009 121
.017 136
.021 143
.036 156
.045 162
.055 165
.072 170
.075 170
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
/END
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Altair Forum User

Hi Prakash,

thanks, but I was looking for a specific example using the pressure dependent function fct_IDp.

I only have the stress-strain functions of the material for compression and tension and I do not know how to calculate the pressure function based on them

Altair Forum User

Hi @Marie

If you have Stress Vs Strain curve, you can use Fct_ID1

Altair Forum User

Hi Prakash,

my material behaves differently in compression and tension, so how can I model this?

Altair Forum User

Hi @Marie

Please check LAW 66, This law models an isotropic tension-compression elasto-plastic material law using user-defined functions

Altair Forum User

Hi Prakash,

I will check it, thanks

Altair Forum User

Hi,

is it correct that the values in the compression and tension yield stress curves of MAT LAW 66 are true stress and true strain?

Altair Forum User

HI,

Yes, most of the materials law use True stress-strain curve except LAW 42