Define a mixed-mode cohesive law

gxiang

I am using cohesive element in Abaqus/Standard to study the mixed-mode fracture of plain concrete. In the part of “Damage initiation”, I used QUADS criterion as follows:

*COHESIVE SECTION, elset=cohesion1, material=adhesive1, response=traction separation, THICKNESS=specified

1.0, 1.0,

controls=visco1

*section controls, name=visco1, viscosity=2.5e-2

*MATERIAL, NAME=adhesive1

*ELASTIC, TYPE=TRACTION

3.70e15, 19.70e15, 19.7e15

*density

1.0,

*DAMAGE INITIATION, CRITERION=QUADS

3.70e6, 19.70e6, 19.7e6

In the part of “Damage evolution”, I am trying “type=displacement, softening=tabular.”

Based on mode-I cohesive strength (3.70 MPa) and mode-I energy release rate (107 N/m), I can generate a table to relate “damage” and “effective displacement” for mode-I fracture. At the same time, based on mode-II cohesive strength (19.70 MPa) and mode-II energy release rate (53.5 N/m), I can generate another table to relate “damage” and “effective displacement” for mode-II fracture. I am thinking how I can combine two tables together to take both mode-I and mode-II into consideration. Any suggestion is welcome!

magiconly_2010

I have the same question for mixed-mode fracture, maybe we can only use UEL or UMAT