Case 2 Case with adhesion

 

The data files for the project are in directory: Cont_001\Exercises\Case 2\Data. Look for ! TODO  text in the datafile and follow the instructions.

 

In this tutorial exercise adhesion in the contact will be added.  To add adhesion the Contact_property and Contact_set should be modified as shown below. In order to observe its effects a vertical upward displacement on the top surface of the top Block will be defined.

 

 

Contact_set

Data File

 

 

* Contact_set                    NUM=1

! ----------------------------------------

 Name                        "Base-Block"

 Geometry_sets IDM=2

   "Base_top_surface"

   "Block_base"

 All_geometry_flag           1                

 Algorithm                   "Penalty"        

 Property_name               "Block_friction"

 Global_update_frequency     1000            

 Search_lost_contact         0                

 Self_contact_flag           0                

 Field_factor                0.5              

 Buffer_factor               1.0                            

 Trigger_search_velocity     10              

 Corner_region_size          0.05            

 

 

1Geometry sets are specified in the Contact_set (this is compulsory in adhesion as All_geometry_flag=1 only works for compression).

 

 

 

 

Contact_property

Data File

 

 

* Contact_property                  NUM=1

! ----------------------------------------

 Name                 "Block_friction"

 Compression_model      1                  

 Compression_properties IDM=1

  /"Normal Penalty"/             500

 Tangential_model       2                

 Tangential_properties IDM=2

  /"Tangential Penalty"/        1000

  /"Friction coefficient"/       0.5            

 Adhesion_model         1

 Adhesion_properties   IDM=1

  /"Normal Penalty"/             500

 

1The compression and tangential models/properties are left unchanged.

2The elastic adhesion model is selected (model 1).

3The adhesion normal penalty stiffness is set to 500 MPa.

 

 

 

 

Load data

Data File

 

 

* Global_loads               NUM=2

! ---------------------------------

 Prescribed_displacement IDM=3 JDM=1

  /Set1/   0 0 1

 Pres_displacement_geom_set   IDM=1

   "Top_Block"

 Pres_displacement_geom_ass   IDM=1

   1

 

 

* Time_curve_data                NUM=2

! ---------------------------------

 Time_curve                     IDM=3

   0.0  1.0  2.0

 Load_factor                    IDM=3

   0.0  -0.05  0.1

 

 

* Load_case_control_data                

! ---------------------------------

 Loadcases                      IDM=2

  1  2

 Active_load_flags              IDM=2

  0  2

 

1The time curve for load 2 is modified in such a way that:

a.From t=0 to t=1 Ma there is vertical downward compression as in the previous example

b.From t=1 to t=2 Ma there is vertical extension (pulling up the top block).

2Load case 1 (lateral displacement) is deactivated in Load_case_control_data.

 

 

 

Results

The result files for the project are in directory: Cont_001\Exercises\Case 2\Results.  Note how the adhesion prevents the top cube to separate from the base prisms.

 

Cont_001_Case2_Results

 

Glyph plot of contact stress vectors at the end of stage 2