Week - 4 - Crash Box Simulation

*Aim:-

-Simulate the crash box model using the LS-DYNA software & understand the concepts of how the conditions produce after the heating car to any particular steady object(Rigid wall)

Objective:-

-In this simulation, we request for the given delivers & compare the results for a 1.2 mm thick & 1.5 mm thick crash box

*Deliverables:-

- Input .k file and output files (d3plot, glstat, sleout, rcforc)
- Animation of the final simulation
- Cross-sectional force generated in the middle of the crash box (along its length)

- Acceleration plot of a node in the middle of the crash box (along its length)
- Maximum directional stress and strain along the length of the crash box (X strain, Y strain etc)
- Plot of all energies (total, internal, kinetic, hourglass, sliding)
- Compare the accelerations and stress/strain plots of 1.2/1.5mm crash boxes

Crash box test is to be conducted by creating all the necessary input keywords:-

1. Material creation
2. Section creation
3. Assigning material & section to their respective parts
4. Rigid wall creation
5. Defining boundary conditions & specifying initial velocity to the box.
6. Creating the contact definition.
7. Model termination to be assigned
8. Binary_D3plot & ASCII_opction define
9. Plotting the result

*Unit system:-

-in the question given, the unit system is:- gm, mm, ms

*Procedure:-

1) Material:-

We create a material card for the shell

2) Section creation:-

-Session shell is taken for the crash box.
-For that we go to Model & part>keyword manager>all>section
-Here provide the element formulation is 2 & thickness is 1.2 mm/1.5 mm

3) Assigning material & section to their respective parts:-

-After the creation of the material & session, the next step is to create the part
-Here there is one part produce. provide the material id and section ID

4) Rigid wall:-

-Now we create the rigid wall
-For that first of all create a new node-set
-For that go to model & part>create> Set data> set node
-Here ew select all nodes of the crash box

-Now we create the rigid wall

-For that go to model & part>create> Rigid wall> rigid wall

-Choose create button and go with planer type

-After that create a wall, and set using just like transalate and rotate opction

-Provide the distance between end of the crash box & rigid wall is 10 mm

5) Definding boundary conditions & specifying initial velocity to the box:-

-Now we provide the velocity to the box

-In the question velocity given is 50 kmph (13.88 mm/ms^2)

6) Creating the contact definition:-

-We create the self contact for a crash box
-For that go to the Model & part>keyword manager>all>contact
-Choose Automatic_single_surface type
-Here we select the slave type is 3(by part) & only select the slave id, don't select the master ID

7) Model termination to be assigned:-

-Now we create control termination card

-Control_termination keyword is crated for the end time provide. we provide end time is 1 ms

8) Binary_D3plot & ASCII_opction define:-

*BINARY_D3PLOT:-

In this keyword the frequency with which the animation is to be crated will be given and is set to 0.01 ms

9) ASCII_OPCTION KEYWORD:-

-in this keyword

1. GLSTAT-Global data
2. MATSUM-Material energies
3. NODOUT
4. RCFORC
5. RWFORC
6. SLEOUT
7. SECFORC
8. NODEOUT

Plotting the result:-

Thickness 1.2:-

1) X and Y Stresses:

t = 1.2 mm

  

t = 1.5 mm

    

2) X and Y Strain:

      

                                       

 3) Nodal-Acceleration:

 t = 1.2 mm                                                                                                                                      t = 1.5 mm

   

 4) Cross-Section Forces:

  t = 1.2 mm                                                                                                                                      t = 1.5 mm

  

5) Kinetic. Internal, Total and Sliding Energies:

  t = 1.2 mm                                                                                                                                      t = 1.5 mm

 

Conclusion:

• The solver deck is set up for the crash simulation & required results were requested using the appropriate *database keyword card
• The analysis ran successfully & post-processing results were done