fct_IDp for Mat LAW 36

Altair Forum User · September 2018

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

Altair Forum User · September 2018

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 · September 2018

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 · September 2018

Hi @Marie

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

Altair Forum User · September 2018

Hi Prakash,

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

Altair Forum User · September 2018

Hi @Marie

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

Altair Forum User · September 2018

Hi Prakash,

I will check it, thanks

Altair Forum User · September 2018

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 · September 2018

HI,

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

fct_IDp for Mat LAW 36

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