Assignment 7-Side Pole Crash Simulation Challenge

Aim:-

• To do deck set-up for side pole crash analysis and run the model.
• Post-processing of results in hyper view and hypergraph.

Objective:-

• First to check the unit system.
• Create type-7 contact with friction value 0.2 with recommended parameters.
• To check for penetration and intersections in the model if present.
• Check for the rigid body if any means make sure all components are connected properly.
• Create a Cylindrical rigid wall with a 0.1 friction value.
• Add mass on the given body to reach the target of 700kg and make COG align approximately with the seat rail.
• Give an initial velocity of 35mph(mile per hour) which is 8.94m/s in x-direction.
• Give time step of 0.0001 for Brick Noda and Inter.
• Give the run time of 80 ms in run card.

crashworthiness tests to conduct in succession.

• Frontal crash test.
• Side pole impact crash test.
• Roof crash test.

In this particular challenge, we will discuss the Side-impact crash test
Since in side crash test, there are multiple standards used on which we have to focus.
FMVSS 214-

• This Final Regulatory Impact Analysis analyzes the potential impacts of new performance requirements and test procedures for head and thorax
  protection systems in side crashes. The rule requires a new 20 mph,75-degree oblique pole test run in two different
  configurations.
• Benefits-The agency estimates benefits for occupants in outboard seating positions in near-side crashes of 12-25 mph delta-V in vehicle-to-pole and
  vehicle-to-vehicle crashes.
• The agency has also found that the side airbags provide benefits to unbelted far-side occupants in side impacts and for belted drivers riding alone in the
  front seat.

Procedure:
1. Import the model in hypercrash.
2. Check for units both in Hypermehs and Hypercrash.
3. Perform mass balancing in hypercrash.
4. Export model in hypermesh.
5. Give time step for Brick,Noda and Inter as 0.0001 milliseconds with respective scale factors.
6. Check for initial penetrarion and intersection.
7. Give initial velocity of 20mph(mile per hour) or 8.94 mps(meter per second).
8. Create type-7 interface contact with friction value as 0.2.
9. Create cylindrical rigid wall with friction 0.1.
10. Create intrusion spring on dasboard position to measure the deformation.
11. Create sections on Driver seat rail and middle rail.
12. Request for TH file as required for this challenge.
13. Run the simulation.
14. Post-processin

1.Check for units both in Hypermehs and Hypercrash:

• Hypermesh
  Go to Solver>cards>Begin card

Hypercarsh:

• In hypercrash while opening itself it will ask to select a unit where we will choose as shown below.

2. Import the model in hypercrash.

• Go to File>import >Radioss>select the file from folder.

3. Perform mass balancing in hypercrash.

• For mass balancing first we will check the initial mass of the model for that,
• Go to Mass > Mass balancing , It will show the initial mass as shown below as 166.3 kg.

• To reach to the mass value to 700kg we need to add 533.7 kg mass more.
• For mass addition, we will use ADMAS option.
• For Add mass
  Go to Load case > Added mass

5. Give time step for Brick, Noda and Inter as 0.0001 milliseconds with respective scale factors.

To give time step go to Model browser> cards > ENG_DT_BRICK

• Give CST type and add value for scale factor and time step.
• Similarly, we will do for NODA.
• But here we will give a scale factor of 0.67

• Now we will give the time step for the interface and we will choose DEL here.
• DEL will activate the delete element command if the time step goes below the given time step.

6. Check for initial penetration and intersection.
Here we will check for initial penetration in the model.
For that go to tool > Penetration check > Select group > Check
After selecting components, hit on check it will show the result below.

Here we can see that 0 collisions were found.
7. Give an initial velocity of 20mph(mile per hour)
Create > Boundary condition > INVEL
Now create INIVEL card here,
Select all components because we are going to give the initial velocity for whole BIW parts.
After selecting component give velocity in Y- direction 0f 8.9408 m/s.

8. Create type-7 interface contact with friction value as 0.2.
Go to create > INTER > Type-7
Name it as self contact for further reference.
Set all the recommended parameters for type-7 contact.


9. Create an Infinite cylindrical rigid wall with friction 0.1.
Go to Create > RWall > CYL

Now create a rigid wall card,
Select a point on the car body, co-ordinates will get displayed.

Normal value to define the z-axis of pole means it will give normal of the pole.
Give sliding friction as 0.1 and Search value as 2000 to caver hole car body.
Since we can see that pole is intersecting so now we will change the co-ordinates to move it at some distance from there.

Infinite cylindrical Rigid wall created now.

Create sections on the Driver seat rail and middle rail.
we are creating sections to analyze the amount of force is travelling from that region.
Select nodes in a way that the frame z-axis should come perpendicular to the global coordinate system.
The frame is created now.
Now after the frame, we will create a section,
We can select the N1, N2 and N3 in the same way we selected the nodes for the frame.
Then we can see the red blu and green arrows which is showing the section plane.

Then in frame id select the frame which we have created earlier.
Now select the elements in the region where we are going to create a section, for that right click on gshell_id and create and edit and select elements.
Put the factors value of deltaT=0.001 and alpha=0.67.

Hit on proceed and we can see the section is created successfully.
Now we can review this section.
Now similarly we will create frame and sections for the right shotgun, for rails according to the node id given and for A piller and for the bumper as well.

12.Output Request:
a).TH for Sectional force in the cross member.
Select all sections we had created.


The intrusion at B pillar,hinge pillar and fuel tank region :

Intrusion is created to check the displacement occured due to collosion. To create an intrusion, right-click
on solver browser >> TH >> NODE >> select the node >> select the skew which was created previously.

Peak velocity of an inner node of the door:

Run the simulation:
To run the simulation go to Analysis > Radioss.
After clicking Radioss click on the input file and save it in a new folder as Test-1 as shown below figure.
Check the include connectors and option as -nt 4.
N indicated how many cores will involve running the simulation.
It will make simulation faster.

After that click on Radioss it will start the simulation.
And wait until the new window popup and show as Radioss job completed.
After running the simulation we will get the animation file, h3d file and also T01 file.
Check for all the files.
Now open 0001.out file and check all the details.
Here we can see all variables in the out file about energy error and mass error also.
So for checking the maximum loss check the last cycle details.

Here in the last cycle of the simulation, we have maximum energy losses where,
Energy error = -2.3 % Acceptable (Range is -15% to +5%)
Mass Error = 0 Acceptable (Range is 0 to 2%)
So the resultant energies are,
1. Internal Energy 0.1144E+05
2. Kinetic Energy 0.1554E+05
3. External work -107.8
4. No of cycles 80001

Post-processing review the simulation using Hyperview.
Plot the graphs using Hypergraph-2D
1. Review the simulation using Hyperview.
Split the screen in two parts now after splitting the screen open hyper view after switching into in 2nd screen.
In hypergraph, window imports the h3d file for a simulation run.

Animation

Now after importing the h3d file on hyperview GUI go for contour activation.
In contour, it will show the simulation graphically and contour lines of load and other properties variation.
To activate contour go to Toolbar > contour
Go to Contour > Displacement > apply contour.

similarly for Von-mises:
According to simulation, we can see that when a car impacts on a pole then firstly force is coming to the structural body is out pert of the gate then b-pillar. And then
it transfers continuously from inner rails to crossectional rails of BIW.
As the force is transferring through the body in the y-direction the amount of force is going to decrease cause at every stage some amount of force going to
absorb in every stage.

Energy graph:

Sectional Forces:
In Cross members 1 and 2:

• Max forces are transmitted by cross member 2 as it is very near to the pole.
• Max force in Cross member-1 is 14.21KN and in Cross, member-2 is 1.6KN.

B-Pillar Intrusion:

• The displacement in B-pillar is 178.53mm.

Hinge Intrusion:

• Maximum displacement in the hinge is 582.91mm.

Fuel Tank Intrusion:

• The maximum displacement is 226.16mm.

Peak velocity at the inner node of the door:

• The maximum displacement for the inner door node is 166.10mm.

Result:-

• Mass balancing is done for the given BIW for a final value of 700kg.
• Created Typ-7 Interface contact for BIW self contact.
• Created cylindrical rigid wall with friction value as given.
• Timestep value is given for all types of elements and contacts.
• Initial velocity 8.94m/s is also given to the BIW body.
• An intrusion spring is created to measure the deformation of the car in the y-direction.
• All TH files are requested for output and then run the model checker.
• Run the simulation and post-processed in hyper view and hypergraph.