Week - 4 - Crash Box Simulation

OBJECTIVE:-

The aim of this project is to analyze the crash analysis of box with different shell thickness and also to obtain the different parameters as follows:-

• Animation of the final simulation
• Input .k file and output files (d3plot, glstat, sleout, rcforc)
• Acceleration plot of a node in the middle of the crashbox (along its length)
• Cross-sectional force generated 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.

Given are the crash box with us. We have to create a new RIGIDWALL (RIGIDWALL_PLANAR). Steel will be the crash box material with the properties as required by the material. The unit system to be used in this simulation must be gm-mm-ms. Assign an initial velocity of 50 kmph(13.88 mm/ms) to the crash box.

PROCEDURE FOLLOWED:-

Import the .k file and check for the model. In this case as given we will be taking unit system as gm-mm-ms.

Starting from the title updation we will proceed further.

Title updation:Model&part>keyword_manager>title>RENAME>accept>done.

After the title rename the part which is auto created to the suitable name - crash_box

Model&part>keyword_manager>part>RENAME>accept>done

Section-shell creation: Two models have to be created for 1.2 mm & 1.5 mm thickness with SECID’s

Model&part>keyword_manager>section>shell>parameters>accept>done

SECID = 1

ELform = 2

T₁ = 1.2 mm,

SECID = 1

ELform = 2

T₁ = 1.5 mm,

Material creation: After the SECID material ID to be created, also the naming of it be done as STEEL, and the properties of steel to be assigned. Material selected as 024_piecewise_linear_plasticity

Model&part>keyword_manager>Mat>024>Properties>accept>done.

MID = 1

RO = 0.00785(1kg/m³ = 10^-6gm/mm³)

E = 2.1E+5(210GPa = 2.1E+5 gm/mm*ms²)

PR = 0.33

SIGY = 250

ETAN = 2.1E+4

FAIL = 10E+20

Assigning these SECID and MATID to the part

Create a node SET ID for INIVEL

Model&part>keyword_manager>set>nodelist>accept>done

Create an initial velocity card, and assign this created nsid to this inivel, also the velocity given to us is 50 kmph, we have to conver it into mm/ms which gives us 13.88 mm/ms in the +ve X-Direction.

Model&part>keyword_manager>initial>velocity>parameter>accept>done.

Rigid wall creation:

Entity creation>rigidwall>cre>planar>1n+nl>select node>tran>distance=10>tran ->apply.

In this way the rigid body is created.

We need to define self contact for the crash box.

Create a SSID, select part crash box as part and apply,

Select SSTYPE as 3(by part id)

Control termination:

We have selected 2.5 ms as endtime

Output requests:

Binary D3 plot: for every dt=0.1

History node id – select a node and insert it in history node id,

Keyword manager>database>history node ID>ID1>title/heading>Insert>accept>done

ASCII options:

Assigning the ASCII outputs, we will need the following outputs for understanding the simulation:

Glstat, Rcforce,rwforc,matsum&Sleout

All dt will be assigned as 0.1 i.e. timestep will be 0.1

Running the simulation in LS run

OUTPUT RESULTS:

Animation of final simulation:-

1.2 mm

1.5 mm

Stress

1.2 mm

1.5 mm

Effective plastic strain:-

1.2 mm

1.5 mm

Acceleration at centre(node):-

1.2 mm

1.5 mm

Energies:-

Energies of 1.2 mm crash box

Energies of 1.5 mm crash box

CONCLUSION:-

The simulation is run successfully and gave Normal Termination. Reading for all the required parameters are stated above.

The .k file can be accessed thorugh the below link:

https://drive.google.com/file/d/1xk81IrY16C4oN5cYvkhImu3UPZFOnanU/view?usp=sharing