Week - 4 - crash box simulation

- Input .k file and output files (d3plot, glstat, sleout, rcforc)

- Animation of the final simulation

- Cross-sectional force generated in the middle of the crashbox (along its length)

- Acceleration plot of a node in the middle of the crashbox (along its length)

- Maximum directional stress and strain along the length of the crashbox (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 crashboxes.

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 Rigidwall creation

5 Definding 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 that, unit system is:- gm,mm,ms.

*Procedure:-

1) Material:-

-Here we seen that shell elements are available in the box, so we create a material card for shell.

-We choose the material card is Piecewise_linear_plasticity(024)

-We use the material is steel for the made of this box.

-We provide the values are:-

*unit conversion:-

*Density:-

`ρ=7850 (Kg)/m^3`

`ρ=7850 *10^3/10^9 (gm)/(cm^3)`

`ρ=7.850×10^(-3) (gm)/(cm^3)`

*Young modulus:-

`E=210Gpa`

`E=210×10^9 pa`

`E=210×10^9 N/m^2`

`E=2.1×10^5 N/(mm^2)`

Poisson ratio is:- 0.33

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.

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

-After the creation of material & session , next step is 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 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 4 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.

-`v=50 (Km)/(hr)`

`v=50 *10^6/(3600*10^3 ) (mm)/(ms)`

`v=0.01388*10^3 (mm)/(ms)`

`v=13.88 (mm)/(ms)`

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.

*ASCII_OPCTION KEYWORD:-

-in this keyword

1)GLSTAT-Global data

2)MATSUM-Material energies

3)NODOUT

4)RCFORC

5)RWFORC

6)SECFORC

7)SLEOUT

-

-Model check:-

-After assigning all the keyword check the model using the model checker and make sure that the file is error file.

-After that save the file as a".k" format.

-Run the file in the solver. if it's end as a normal termination then model is correct.

9) plotting the result:-

1)Stress contour animation for thickness 1.2:-

Stress contour animation for thickness 1.5:-

*Strain contour animation for thickness 1.2:-

Strain contour animation for thickness 1.5:-

*Various plots:-

1)Global data for tickness 1.2:-

*Global data for tickness 1.5:-

2)Rigid wall force for thickness 1.2:-

*Rigid wall force for thickness 1.5:-

*Stress vs strain dia:-

-For draw the stress vs strain diagram, first of all plot a resultant stress vs time diagram & also plot a resultant plastic strain vs time.

-After that use xy plot opction & choose this file.

*For 1.2 thickness:-

-Here we seen that yield stress is around 250 Mpa, after that plastic region start.

*For 1.5 thickness:-

*Conclusion:-

-The solver deck is setup for the crash simulation & required results were requested using the appropiate

*database keyword card.

-The analysis ran sucessfully & post-processing results was done.