Week - 4 - Crash Box Simulation

Aim:in this challenge i have to perform crash box simulaton.generally in automotive we will hit the car to the barrier but now for understanding the crash simulation instead of taking the car i am taking a rectangular box this box will move with some velocity and get hits the rigid wall then the rectangular box get crashed.

after crashed into the wall we will check energies like kinetic,inernal,total energies of crash box.and also we will check vonmisses stresses.crash box will play major role which will absorb the more energies.

imported the meshed .k file inthe ls-prepost for running the simulation.the simulation is carreied out into 2 different paramaters of thicknesses which are 1.2mm,1.5mm.we will run the simulation with 13.8mm/ms of velocity.and termination time is 10ms.

Procedure:

create the sec id for crash box in keyword manager by selecting the *section_shell option in this i have given elform2,shrf=0.833,nip=2,thickness1.2mm.

e-reate the material id for crash box in the keyword manager by selecting the *Mat_Elastic option in this i have given the material properties are RO=7.8e-3,2.1e5,pr=0.3.

updated the both sec id and mat id in the *part

now i have given the termination time in *control_termination which is End time 10ms

i have given the automatic_single_surface contact in*contact in this the rectangular it self considered as both slave and master. the crashbox given as ssid.

then i have created the node set in the create entity for the entire crash box.then i assigned the velocy in the *intial_velocity

assigned the node set id in this and velocity i have given in the X-direction i.e 13.8mm/ms.

now i have taken the RIGID_WALL_PLANAR in this i have created the rigid_wall in x-direction with distance of 10mm.

finally,i have given the output cards which are in *Database_option.those are Binary_D3plot,Extent_binary,history_node and also given global,matsum,sle_out,node_out,rc_force energies are given in the ASCII_option

Results:

plot Results of kinetic,internal,total enrgies and also check vonmisses stresses

from these which is absorbing the more enrgy with respect to the time.

for thickness 1.2mm max vonmises stress=6.512e2

min vonmises stress=0.0e0

for thickness 1.5mm max vonmises stress=6.292e2

min vonmises stress=0.0e0

the above figure indicates the max and min vonmises stresses of different thickness.

we know that if the thickness increases stiffness also increases then more stiffness will results lower the stress values.

for thickness 1.2mm global energies are ploted below.

for thickness1.2mm sleout energy i.e slave energy are ploted below.

for thickness1.2mm secforce are ploted below.

for thickness1.2mm directional force along X-Y direction highest stress value is 9.915e1 and lowest valueof stress is -7.871e1

for thickness 1.2mm strain along X-Y direction highest strain value is 5.166e4 and lowest stain value is -5.165e-4

for thickness 1.2mm acceleration of Node no A 5038 ploted below.

for thickness 1.5mm accleration of Node no A 5038 ploted below.

for thickness1.5mm the the erergies are ploted below.the graph goes up here when compared to 1.2mm thickness of crash box.

for thickness1.5mm sec force also increases when compared to 1.2mm thickness of crashbox.and graph is ploted below.

for the above accleration for Node no 5038 is increased when the thickness is 1.5mm and for 1.2mm thickness of the acceleration decreased.

if the thickness increases then acceleration also increases.not only the accleration but also increased the stresses.and stiffness also increased.

Conclusion: the crash box simulation is carried out in ls-prepsot software. if i compare the thickness of the crash box 1.2mm and 1.5 mm here 1.5mm crash box having more energies,stresses,accelerations when compare to 1.2mm thickness of crash box.so if the thickness increases stress also increases then stiffness also increases.shown in the above graphs.