Example of Mohr Coulomb Soil Stability not working

[dichtstoff]

Hello,

I’m interested in these example:

Mohr Coulomb Soil Stability

Hi, YouTube tutorial Mohr Coulomb / Soil Stability. [CalculiX Launcher 3beta Mohr Coulomb soil - Slope Stability]

so i rebuild these example but it is not working!
What is the issue with my rebuild?

i use C3D6 elements:

thnk you for your help

wbr dichtstoff

MSCC.fbd

pnt ! 0 0 0
pnt ! 10 0 0
pnt ! 30 0 0
pnt ! 40 0 0
pnt ! 40 0 15
pnt ! 30 0 15
pnt ! 10 0 5
pnt ! 0 0 5
pnt ! 30 0 5

line ! D001 D002 110
line ! D002 D007 105
line ! D007 D008 110
line ! D008 D001 105

line ! D002 D003 120
line ! D003 D009 105
line ! D009 D007 120
line ! D007 D002 105

line ! D003 D004 110
line ! D004 D005 115
line ! D005 D006 110
line ! D006 D009 110

line ! D006 D007 122

GSUR A001 + BLEND + L001 + L002 + L003 + L004
GSUR A002 + BLEND + L005 + L006 + L007 + L002
GSUR A003 + BLEND + L009 + L00A + L00B + L00C + L006
GSUR A004 + BLEND + L007 + L00C + L00D

#div all mult 2

elty all TR3U
mesh all

swep all block tra 0 1 0 1

elty all TR6

seta nodes n all

enq nodes fix_side rec 0 _ _ 0.1
enq nodes fix_side rec 40 _ _ 0.1

enq nodes fix_bottom rec _ _ 0 0.1

plot n fix_side b
plus n fix_bottom y
plus e all
view elem

prnt se

send all abq
send fix_side abq nam
send fix_bottom abq nam

MSCC.inp

*HEADING
Model: MCSS

*INCLUDE, INPUT=all.msh
*INCLUDE, INPUT=fix_bottom.nam
*INCLUDE, INPUT=fix_side.nam

*MATERIAL,NAME=ABAQUSMCWD
*USER MATERIAL, CONSTANTS=5
2e7,0.26,8700,10.35,10.35

*DENSITY
1580

*SOLID SECTION, Elset=Eall, Material=ABAQUSMCWD

*STEP, NLGEOM,

*STATIC, SOLVER=SPOOLES
0.1,1

*BOUNDARY
Nall,2,2,0
Nfix_side,1,1,0
Nfix_side,2,2,0
Nfix_bottom,1,1,0
Nfix_bottom,2,2,0
Nfix_bottom,3,3,0

*DLOAD
Eall,GRAV,9.810,0.0000,0.0000,-1.000

*NODE FILE
U
RF
*EL FILE
S
*END STEP

[xyont]

probably, the distribution is not included ABAQUSMCWD material, try another one from SourceForge or using Mohr Coulumb material available instead of Umat.

 *MOHR COULOMB
Friction angle (degrees), Dilation angle (degrees), Temperature (optional)
*MOHR COULOMB HARDENING
Cohesion yield stress (c), Equivalent plastic strain, Temperature (optional)

another needed to check is in element type by elty all TR3 commands of CGX, make sure it has plane strain models (CPE3)

[dichtstoff]

i can change to CPE3 elements,
is it helpfull to change to displacement the top line
instead of *DLOAD

from example i get these input:

**** YOUNG’S Modulus E 2e7
**** Poisson’s ratio nu 0.26
**** Cohesion c 8700

*MATERIAL,NAME=MC
*ELASTIC
2e7,0.26

**** Friction angle f in degrees 10.35
**** Dilation angle ? in degrees 10.35

*MOHR COULOMB
10.35,10.35

**** Cohesion yield stress c 8700

*MOHR COULOMB HARDENING
8700,1

is these translation or adaption correct?
i have the paper of
Mohr-Coulomb material - SLOPE STABILITY test in Calculix with J.C. Clausen UMAT
where i have different values:

**** YOUNG’S Modulus E 20000
**** Poisson’s ratio nu 0.26
**** Cohesion c 13.5

*MATERIAL,NAME=MC
*ELASTIC
2e4,0.26

**** Friction angle f in degrees 15.8
**** Dilation angle ? in degrees 15.8

*MOHR COULOMB
15.8,15.8

**** Cohesion yield stress c 13.5

*MOHR COULOMB HARDENING
13.5,1

is there an influence of elements with first or second order?

thnx for your time and your help

Update: second order elements i get these result:

[dichtstoff]

thnx a lot,
i have fixed all issues
i get it worked with CPE6 elements:

MCSS

Mohr Coulomb Soil Stability

MCSS.fbd

pnt ! 0 0 0
pnt ! 10 0 0
pnt ! 30 0 0
pnt ! 40 0 0
pnt ! 40 15 0
pnt ! 30 15 0
pnt ! 10 5 0
pnt ! 0 5 0
pnt ! 30 5 0

line ! D001 D002 110
line ! D002 D007 105
line ! D007 D008 110
line ! D008 D001 105

line ! D002 D003 120
line ! D003 D009 105
line ! D009 D007 120
line ! D007 D002 105

line ! D003 D004 110
line ! D004 D005 115
line ! D005 D006 110
line ! D006 D009 110

line ! D006 D007 122

GSUR A001 + BLEND + L001 + L002 + L003 + L004
GSUR A002 + BLEND + L005 + L006 + L007 + L002
GSUR A003 + BLEND + L009 + L00A + L00B + L00C + L006
GSUR A004 + BLEND + L007 + L00C + L00D

div all mult 2

elty all tr6u
mesh all

elty all tr6e

seta nodes n all

enq nodes fix_side rec 0 _ _ 0.1
enq nodes fix_side rec 40 _ _ 0.1

enq nodes fix_bottom rec _ 0_ 0.1

plot n fix_side b
plus n fix_bottom y
plus e all
view elem

prnt se

send all abq
send fix_side abq nam
send fix_bottom abq nam

MCSS.inp

*HEADING
Model: MCSS

*INCLUDE, INPUT=all.msh
*INCLUDE, INPUT=fix_bottom.nam
*INCLUDE, INPUT=fix_side.nam

**** YOUNG’S Modulus E 20000.0 [kN/m²]
**** Poisson’s ratio nu 0.26 [-]
**** Cohesion c 13.5 [kN/m²]

*MATERIAL,NAME=MC

*ELASTIC
2e4,0.26

*MOHR COULOMB
15.8,15.8

** Friction angle f in degrees 15.80
** Dilation angle ? in degrees 15.80

*MOHR COULOMB HARDENING
13.5,1

** Cohesion yield stress c
** Equivalent plastic strain.

*SOLID SECTION,ELSET=Eall,MATERIAL=MC

*DENSITY
3.5

*STEP, NLGEOM, INC=200

*STATIC, SOLVER=SPOOLES
0.01,1

*BOUNDARY
Nfix_side,1,1,0
Nfix_bottom,1,2,0

*DLOAD
Eall,GRAV,9.810,0.0000,-1.0000,0.0000

*NODE FILE
U
RF
*EL FILE
S
*END STEP

[xyont]

p.s slope stability analysis can be less accurate using standard Mohr-Coulomb materials due to lack of tension cut-off, it can be verified by request and plotting plastic strain results of failure surfaces.