Case 3 Switch to standard constitutive and contact models

 

In this exercise, after the application of the tectonic load in Case2, subsequent stages will be performed in order to switch from elastic to standard contact model first and then switch from elastic to standard constitutive model. The transition from elastic to standard models can be performed gradually. For more information see keywords Contact_initialization_type and Stress_initialization_type in Geostatic_control_data.

 

To perform this exercise copy the Case 2 datafile as a template. Then copy and paste twice the Geostatic_control_data and Control_data data structures to add two extra control stages. Then modify The geostatic control data structure keyword options as shown bellow.

 

Stage 3: Contact release

Data File

 

 

* Geostatic_control_data

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

 Stress_constitutive_model            "Elastic"

 Stress_initialisation_type           "None"

 Contact_constitutive_model           "Standard"

 Contact_initialisation_type          "Release"  

 

   

* Control_data

! ========================================

 Control_title         "Contact release"

 Solution_algorithm                    1  

 Maximum_number_time_steps       1000000

 Duration                           0.25

 Factor_critical_time_step           0.5

 Output_frequency_plotfile            -1

 Screen_message_frequency            500

 Output_frequency_restart             -1  

 

1The stresses from the previous stage will be kept by setting Stress_initialization_type to "None" (no stress initialization following the Geostatic_data input).

 

2The contact model is switched from elastic to the Coulomb frictional model (set in the contact data) by setting the Contact_constitutive_model as "Standard".

 

3A gradual transition from the Elastic contact to the Coulomb frictional model will be performed by setting Contact_initialization_type as "Release"

 

4Control_data is identical to the first stage (see Case1).

 

 

 

Stage 4: Constitutive model release

Data File

 

 

* Geostatic_control_data

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

 Stress_constitutive_model            "Standard"

 Stress_initialisation_type           "None"

 

 

* Control_data

! ========================================

 Control_title     "Constitutive release"

 Solution_algorithm                    1  

 Maximum_number_time_steps       1000000

 Duration                           0.25

 Factor_critical_time_step           0.5

 Output_frequency_plotfile            -1

 Screen_message_frequency            500

 Output_frequency_restart             -1  

 

1During this stage the constitutive model is switched from elastic to the SR4 model with poroelasticity (set in the material data) by setting the Stress_constitutive_model as "Standard".

 

2The stresses from the previous stage will be kept by setting Stress_initialization_type to "None".

 

3Control_data is identical to the first stage (see Case1).

 

The data  and result files for the project are in directory: geost_002\Exercises\Case3