Week - 3 Drop test Challenge

Aim:

To create an input deck from scratch and creating results similar to the situation, where the phone would bounce back in the same direction after the impact.

Procedure:

1. Open the given model:
The given file is opened using File --> Open --> LS-Dyna Keyword file

2. Material card creation:

1. Select Keyword Manager present on the right side of the tool bar
2. Once the keyword manager window opens, select ALL
3. Go to MAT --> Select 001-Elastic --> Keyword Input Form window opens
4. In the Keyword Input form window, enter the Material name in TITLE, a unique material ID in MID and the other material properties like density, Youngs Modulus and Poission ratio. Unit of measurement followed in this project is kg-m-s. Material for the phone is chosen as Aluminum and its properties are entered in the material card.
   
5. Similarly, the ground is considered as a rigid material. So, MAT --> 020-RIGID is selected. Steel is considered as the material for the ground and its properties are entered. Also, a unique material ID is created for it. The ground is considered as a body that does not rotate or translate. Hence, corresponding values for it are entered in CON1 and CON2 fields.
   

3. Section card creation:

1. The model contains two parts - Phone and ground.
   • Phone is considered as a solid part
   • Ground is considered as a shell part
2. Ground section creation - In the Keyword manager, select All --> Shell --> Keyword Input Form window opens --> Enter SECID, ELFORM, T1, T2, T3 & T4 --> Select Accept --> Done
   
3. Phone section creation --> In the Keyword manager, select All --> Solid --> Keyword Input Form window opens --> Enter TITLE, SECID, ELFORM --> Select Accept --> Done
   

4. Part card creation:

1. In the Keyword manager, select All --> Part --> Enter TITLE --> Enter PID --> Select the small dot button near SECID --> Select the correct section in the link section window --> Done --> Repeat the same in MID field and select the appropriate material --> Select Accept --> Select Done
   
2. Repeat the process for the second part.

5. Initial Conditions:

1. In the Toolbar on the right side of the window, select Create Entity
2. Select Initial --> Velocity
3. In the Keyword Input form window, enter the velocity Vz as -10 m/s --> select Accept
4. Select the dot button near NSID --> Link_SET_NODE window opens --> Select NewEntity --> Entity creation window opens
5. In the Entity creation window, select Pick --> Select ByPart --> Select the phone part --> Apply
6. In the Keyword Input form window, select Accept --> Done
   

6. Contact card creation:

1. In the Keyword manager, select All --> CONTACTS --> AUTOMATIC_SURFACE_TO_SURFACE --> Enter CID & TITLE --> Select "3" which denotes Part ID in SSTYP & MSTYP --> Select Phone body as slave in SSID & Ground body as Master in MSID --> Click Accept --> Done
   

7. Control card creation:

1. In the Keyword manager, select All --> CONTROL --> TERMINATION --> Enter ENDTIM value --> Click Accept --> Done
   
2. In the Keyword manager, select All --> CONTROL --> HOURGLASS --> Enter THQ as 1.0 --> Click Accept --> Done
   

8. Database card creation:

1. In the Keyword manager, select All --> DATABASE --> Select BINARY_D3PLOT --> Enter DT as 0.5 --> Click Accept --> Done
   

9. Save the file using File --> Save --> Save Keyword as a .k file

10. Run the .k file using File --> Run LS Dyna --> LS Run window opens --> Select the saved .k file in the INPUT field --> Select the "Add job to local queue" to run the simulation --> A command prompt window opens --> Once the simulation is done, the processing in the command prompt stops

11. View the output:

• Select File --> Open --> LS Dyna Binary Plot --> Select the file
• In the right side toolbar, select Fringe Component --> Fringe Component window opens
• Select the required output and animate the simuation using the options in the animate window
• Similarly, using History option, the information an element/part can be viewed as plot
• In the below picture, one of the bottom element of the phone is selected and observed for the effective stress at that point. The stress at that element is maximum at 3 sec and the build up of stress sat that element tarts at 2 sec. It is to be noted that the time at which the phone impacts the ground is at 2 sec and the maximum stress induced in the element is at 3 sec. After 3 seconds, the stress at the element starts decreasing and then starts increasing again at 4 sec.
  
  
  
  

Learning outcomes:

• The procedure for creating keywords using keyword manager
• Setting up the simulation with appropiate keyword after understanding the scenario to be simulated
• Extraction of results from simulation using plots

Conclusion:

An input deck from scratch is created and results similar to the situation, where the phone would bounce back in the same direction after the impact is created.