Project

Side Crash Analysis of Neon BIW

Objective: To perform side crash analysis on the given model and obtain the required output requests as mentioned below:

Case Setup and Execution:

Open the given 'neon_side_reduced_0000.rad' file in Hypermesh and Hypercrash simultaneously.
Keep the unit system as 'Kn mm ms kg' in Hypercrash.
Run the model checker in Hypercrash and make the changes required in Hypermesh and make sure that there are no penetrations and intersections.
TYPE 7 interface is selected as it is recommended for the crash analysis and self contact is given for the whole model (Master segments and slave nodes) to prevent self penetration with the following properties:

Istf=4

Igap=2

Idel=2

Fric=0.2

Gapmin=1

Inacti=6

Iform=2 .

A rigid wall is created in the right of the B Pillar (height is along z-axis) with friction as 0.1, sliding as 2, Dsearch as 1000 and diameter of 254mm.
Mass added to the system to reach the target mass 700kg and the COG position matches the full scale model.
Initial velocity of Vx=15.56 mm/ms is assigned to the model which is in +ve y-direction.
Timestep is set to 0.0005ms and run/termination time to 80ms.
Cross-sections were created on cross members of BIW for checking sectional forces.
Output blocks are created for sectional forces, intrusions and peak velocity of the inner node of the door.
Now run the model in RADIOSS.
Now open the obtained .h3d file in hypervview for results and .T01 file in Hypergraph 2D for plotting graphs.

RESULTS/OUTPUT REQUESTS:

Sectional force in the Cross member:

The maximum force recieved by cross member 1 section is 0.88kN and by cross member 2 section is 3.82kN.
Cross member 2 is recieving more force because of the difference in cross section along the length of cross member and difference in end conditions at the left rocker. The cross member 2(blue in figure below) has its cross section fully covered by the rocker and the load path is closer to centroid than cross member 1.

Intrusion at B Pillar:

Intrusion at Hinge Pillar:

Intrusion at Fuel Tank:

The intrusion is measured in hyperview and intrusion is 715mm (1317-602).
The reason fuel tank intrusion is so large is that there are very few components which support fuel tank area against external load.
To reduce the fuel tank intrusion, use high strength material for B-Pillar, Rocker Panel and cross members so that they can reduce the lateral deformation during a side impact event OR add some extra support material at the location.

Peak Velocity of inner node of the door:

Peak velocity of of node 337773 is 16 mm/ms.
This is more or less the same velocity experienced by the passengers while in a crash.

Energy Plots:

Kinetic energy is high at the start and goes on decreasing as the KE is converted into internal energy absorbed by elements during deformation and the total energy is nearly constant maintaining the energy balance and energy error is -1%.
A gradual increase in contact energy is absorbed as more elements come into conatct with each other.
Initially there was an increase in hourglass energy but it becomes contact after a while.
The kinetic energy is 85500 joules initially and reduces to 70800 joules.

Results and Conclusion:

COG location and mass of the car are very important.
Impact forces are very high at the beginning and then reduces gradually.
Major deformation is happening at the mid section of the car, which means high strength components and materials must be used at these locations.

Ship work like this
in your own course.