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Brittle cracking in brittle materials

surot's picture

Hi there,

 I am trying to simulate a crack opening process in ABAQUS. I start up from a simple model of plate with a notch subjected to tension. I would like to see the crack opening. To model a brittle mnaterial behaviour I have added a brittle cracking with sub-option brttle failure and brittle shear.

Please look at dat file:

*Heading

  *Node

  *Element, type=CPS3

  *Element, type=CPS4R

  *Nset, nset=ASSEMBLY_PART-1-1__PICKEDSET2

  *Elset, elset=ASSEMBLY_PART-1-1__I1

  *Elset, elset=ASSEMBLY_PART-1-1__I2

  *Elset, elset=ASSEMBLY_PART-1-1__PICKEDSET2

  *Nset, nset=ASSEMBLY__PICKEDSET15

  *Elset, elset=ASSEMBLY__PICKEDSET15

  *Elset, elset=ASSEMBLY___PICKEDSURF14_S1

  *Elset, elset=ASSEMBLY___PICKEDSURF14_S2

  *Elset, elset=ASSEMBLY___PICKEDSURF14_S4

  *surface, type=ELEMENT, name=ASSEMBLY__PICKEDSURF14

  *surface, type=ELEMENT, name=ASSEMBLY__PICKEDSURF14

  *material, name=MATERIAL-1

  *brittlecracking, type=DISPLACEMENT

  *brittleshear

  *brittlefailure, cracks=1

  *density

  *elastic

  *solidsection, elset=ASSEMBLY_PART-1-1__I1, material=MATERIAL-1

  *solidsection, elset=ASSEMBLY_PART-1-1__I2, controls=EC-1, material=MATERIAL-1

  *sectioncontrols, name=EC-1, elementdeletion=YES

  *solidsection, elset=ASSEMBLY_PART-1-1__I1, material=MATERIAL-1

  *solidsection, elset=ASSEMBLY_PART-1-1__I2, controls=EC-1, material=MATERIAL-1

  *solidsection, elset=ASSEMBLY_PART-1-1__I1, material=MATERIAL-1

  *solidsection, elset=ASSEMBLY_PART-1-1__I2, controls=EC-1, material=MATERIAL-1

  *output, field, variable=PRESELECT

  *output, history, variable=PRESELECT

  *Step, name=Step-1

  *Step, name=Step-1

  *dynamic, explicit

  *boundary

  *dsload

  *output, field, variable=PRESELECT

  *output, history, variable=PRESELECT

  *endstep

  *surface, type=ELEMENT, name=ASSEMBLY__PICKEDSURF14

  *Step, name=Step-1

  *dynamic, explicit

  *boundary

 

 ***WARNING: THE OPTION *BOUNDARY,TYPE=DISPLACEMENT HAS BEEN USED; CHECK STATUS 

             FILE BETWEEN STEPS FOR WARNINGS ON ANY JUMPS PRESCRIBED ACROSS THE 

             STEPS IN DISPLACEMENT VALUES OF TRANSLATIONAL DOF. FOR ROTATIONAL 

             DOF MAKE SURE THAT THERE ARE NO SUCH JUMPS. ALL JUMPS IN 

             DISPLACEMENTS ACROSS STEPS ARE IGNORED

 

 ***WARNING: DEGREE OF FREEDOM 6 IS NOT ACTIVE IN THIS MODEL AND CAN NOT BE 

             RESTRAINED

  *output, field, variable=PRESELECT

  *output, history, variable=PRESELECT

  *endstep

 

     - (RAMP) OR (STEP) - INDICATE USE OF DEFAULT AMPLITUDES ASSOCIATED WITH THE STEP

 

 

 

                            P R O B L E M   S I Z E

 

 

          NUMBER OF ELEMENTS IS                                   511

          NUMBER OF NODES IS                                      557

          NUMBER OF NODES DEFINED BY THE USER                     557

          TOTAL NUMBER OF VARIABLES IN THE MODEL                 1114

          (DEGREES OF FREEDOM PLUS MAX NO. OF ANY LAGRANGE MULTIPLIER

           VARIABLES. INCLUDE *PRINT,SOLVE=YES TO GET THE ACTUAL NUMBER.)

 

 

 

                              END OF USER INPUT PROCESSING

 

 

 

     JOB TIME SUMMARY

       USER TIME (SEC)      =  0.13000    

       SYSTEM TIME (SEC)    =  4.00000E-02

       TOTAL CPU TIME (SEC) =  0.17000    

       WALLCLOCK TIME (SEC) =          1

 

*Brittle Cracking, type=DISPLACEMENT

 3e+06,    0.

 3e+06, 1e-05

*Brittle Shear

   1.,    0.

  0.5, 1e-06

 0.01, 1e-05

*Brittle Failure, cracks=1

 1e-05,

 

The analysis is completed byt I cannot see the crack opening 

Comments

surot's picture

I have already solved my problem :)

Andrealina's picture

Hi Mr

I want to define the SiC matrix of the C/SiC ceramic composite material ,and i want to use the brittle cracking model .But i can't make the inner relationship among brittle cracking ,brittle shear and brittle failure clear . And even I don't know how to define each parameter in the brittle cracking model , I don't know the rules .

I hope you can help me. Thank you very much!

 

                                                                                                                                                   Andrealina

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