Assignment 6-Frontal Crash Simulation Challenge

Aim: Frontal Crash Simulation for given model and study of forces on various location and also study od intrusion to brake and accelerator pedal location .

Procedure:

Import the given model Using hypermesh>>radios solver >> import >>import  solver deck>> select the path in file >> Import

 

Task 1: Check unit system and either follow[Mg mm s] or [Kg mm ms].

Go to model>> card>> BEGIN_CARD

As checked we are following
Length: mm
Mass: Kg
Time : ms

 

Task 2: Create appropriate interface ,friction 0.2 and recommended parameters.

Right click on solver tab>>create > >inter>> type_7

 

Gmod_id (s): select all component (72)

 

Surf_id (M): select all component (72)

 

Istf: 4
Igap:2
Idel: 2
Fscale_gap :0.9

Stmin: 1
Fric: 0.2
Gapmin: 0.5

Task 3: Make sure of no penetrations and intersection.

For this go to tool >> penetration check

Select type7_inter group

 

Click on check

 

Thus we found zero intersection and penetration element

Task 5: Create rigid wall with friction 0.1.

For this we will 1^st create outermost node to the front side of car and offset it with 50 mm

Geom>> temp node>> select node >> add

 

Now go to tool>>translate >> node >> select node and duplicate >> give direction as global X axis >> magnitude 50 >> click on translate  two time so that node will translate 100 mm

 

Now go to solver browser right click >> create >> Rwall>>plane

 

Set data as below
geometry wall : infinity wall
Engineering data : select node which created for rigid wall

Normal : -1 in x axis

Support:

Slide: 2 slide with friction

Dsearch : 2000
FRIC; 0.1

 

Rigid wall is create as shown below ‘

 

Task 6 : Compare the model weight with the full scale 300k nodes model and use added masses to reach target weight 700kg while getting CG about the required range.

Now we will 1^st check the total mass and COG of the vehicle

Tool>>mass details>> mass, cog and inertia

 

Total Mass: 188.021443729204

Required mass : 700 ; so we will add mass with magnitude of 512 kg

COG

 

To add mass
right click on solver browser >> create >> admas

 

Mass type: 1 Mass/N is added to each node of the group
right click on Grnd_id: click on create /edit

Entity_id: select node as given below

Mass : 512

 

Now check again for mass and COG

Total mass is 700 kg

 

COG of vehicle

 

Task 7 : Initial velocity 35 mph.

To create initial velocity we will right click on solver >>create > > boundary condion >> INIVEL

 

Convert 35 mph to mm/ms which is 15.65 mm/ms

Grnd_id : select all nodes of vehicle
Type: TRA Translational material velocity
velocity component : x-direction (15.65) ; y-0,z-0

 

Task 8: Use model checker to ensure good quality.

To perform model check
tool>>model checker >> radios block

 

Right click on model checker and run

 

As we have run model checker and not found any error to solve , so we will proceed

 

Task 9: Time-step :0.5 to 0.1 microseconds.

To set this we will go to model browser >>Card>>ENG_ANIM_DT

Tfreq: 5 ms( this we will set to reduce simulation time)

 

Task 10: Run for 80 ms

For this we will go to Model browser >> Card >> ENG_run

Tstop : 80

 

Task 11:

Output requests:

• Sectional force in the rails at location of indicated node 174247.
• Axial force received on the rails from bumper.
• Shotgun cross sectional forces.
• A pillar cross section.
• Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
• Intrusions on the dash wall 66695,66244.

Procedure: show a temp node for node id 174247

 

Now right click on solver browser >> create >> frame >> mov

Click origin as generated node , z axis and YZ plane node as shown below

 

Now create section

To create section right click on solver browser >> create >> sect >> sect

Select N1, N2 and N3 as previous node which used to define the frame
Frame_Id: select 1 ( as we create frame have id 1)

DeltaT: 01.
Alpha: 0.628

Gshell_id: right click and click on create/edit

And select elements as shown below

 

 

Now create Time history plot for output

For that right click on solver browser >> create >> Th >>section

Enitiy IDs: select crosssection 1 ( which we created)

Num Varible : 1
Sectio: DEF

 

Now we will repeat same process for bumper , shotgun, A pillar on both side

Now to create Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).

We will create temp node on on below location ( below the B pillar)

 

To create accelerometer right click on solver browser >> create >> accel

 

Node Id: select node
F_out: 1.65

 

Create Th out file

For that right click on solver browser >> create >> Th >> Accel

 

Entity Id : select accelerometer 1 ( which we created now )
Num_ Variable : 1
Accel :DEF

 

Create same for other opposite side

Now create Intrusions on the dash wall 66695,66244.

Now node visible for above node id

 

Now we will create two collector in model >> component to collect two weak spring with stiffness and mass minimum

 

Create property for spring

Right click on model browser >> create >> material

Mass : 0.001
k1 : 0.001

 

Assign this material to spring component

 

Now create 2 spring 1 in each collector as shown below

 

Now create time history plot for this spring

Right click on solver browser >> create >> Th >> Part

 

Entity id: select 1 component
Num_variable : 1
Part : DEF

 

Create Th file for other component

Now export the model in required location ( select path )
export : all

 

For run the simulation
go to analysis
Radioss
export option : all
Include Connector : checked
Option : -nt 4
click on radios

 

After simulation complete .

 

Time taken to run simulation: 1:06:03

Result :

Displacement : Max displacement : 9.6E+2

 

Von mises stress

 

Plastic strain:

 

Energy Error : -1.7%
Mass Error : 0.2974E-01  

Plot :

Internal Energy

 

Kinetic Energy

 

Hourglass energy

 

Total Energy

 

 

1. A Pillar (Left ) cross sectional force

 

on the left A-Pillar the maximum resultant force experienced at cross section is 0.838 KN.

2.ShotGun (Left) Cross Sectional force

 

on the left shot gun the maximum resultant force experienced at cross section is 10.93 KN.

3. ShotGun (Right ) Cross Sectional force

 

on the right shot gun the maximum resultant force experienced at cross section is 17.65  kN.

4. A Pillar (Right ) cross sectional force.

 

on the right A-Pillar the maximum resultant force experienced at cross section is 0.797 KN.

5. Axial force received Bumper (left)

 

Axial forces received on the rails from bumper Left  is 6.77 KN 

6. Axial force received Bumper (Right )

 

Axial forces received on the rails Right  from bumper is 5.13 KN 

7. Sectional force received at the rail cross section (left)

 

 The sectional force experienced  at the left rail  16.10 kN.

8. Sectional force received at rail cross section ( right )

 

The sectional force experienced  at the Right  rail  19.90 KN

9. Acceleration curve received at the base of B pillar (left)

 

on the left base of B pillar the maximum resultant acceleration experienced is 1.818 mm/ms^2.

10. Acceleration curve received at the base of B pillar (Right )

on the right base of B pillar the maximum resultant acceleration experienced is 2.10 mm/ms^2

total intrusion at node 66695;

 

Total intrusion is 222.43 mm

total intrusion at node 66244

 

Total intrusion is 165.51 mm

Rigid wall force

 

Conclusion :  The given model was simulated for the frontal crash using Radios

The graphical results were plotted for all the test cases. From the simulation, it can be observed that there was minimum deformation in the cabin, and also minimum intrusion was found in the driver's seat area.