Abaqus - cohesive concrete and epoxy

Hi,



I was browsing through this forum which I find very helpful.



I am trying to model a simple shear pull out test by simulating debonding in abaqus.

epoxy is bonded between concrete and frp.

i am pulling frp from one end by applying a load while other end of concrete is fixed.

epoxy is modeled as cohesive with quad damage and traction

interaction has been defined as hard contact, cohesive and damage (initiation, evolution and stabilization).

automatic stabilization is also provided by inputing the damping factor.

the mesh size for concrete and frp is 1 mm while for cohesive is 0.5 mm.

the initial, minimum and maximum time increments are 1E-9, 1E-36,0.1

the epoxy layer is connected to concrete and frp by tie constraints.



after analysis, only 1 interaction with 5 increments takes place and no stresses can be seen in epoxy.

the error messages that i get are -

large flux ratio

numerical singularities 

no pivots



i have exhausted all option of trying to make this work.

please help me.



following is the input file with the necessary details.





*Heading

** Job name: Job-1 Model name: Model-1

** Generated by: Abaqus/CAE 6.10-EF1

*Preprint, echo=NO, model=NO, history=NO, contact=NO

**

** PARTS

...........

..........

** INTERACTION PROPERTIES

** 

*Surface Interaction, name=IntProp-1

1.,

*Friction, rough

*Surface Behavior, pressure-overclosure=HARD

*Cohesive Behavior, REPEATED CONTACTS

3304.,1180.,1180.

*Damage Initiation, criterion=QUADS

2.15, 3.21, 3.21

*Damage Evolution, type=ENERGY, mixed mode behavior=POWER LAW, power=1.557

0.0893, 0.9, 0.9

*Damage Stabilization

1e-06

** 

** INTERACTIONS

** 

..........

..........

** 

** STEP: Step-1

** 

*Step, name=Step-1, nlgeom=YES, extrapolation=PARABOLIC, inc=1000

*Static, stabilize, factor=200., allsdtol=0, continue=NO

1e-12, 1., 1e-36, 1.

**