Full Frontal Crash Analysis

Objective:

To simulate a full-frontal crash of the given car model

Steps followed:

1. The unit system used is kg/ mm/ ms

2. Check and correct the element properties wherever needed. (Ishell = 24 & Isolid = 24)

3. Create TYPE 7 interfaces for Bumper-Rail contact and Self Contact. The properties used are:

Parameter	Value
Istf	4
Igap	3
Idel	2
Stmin	1.0
Fric	0.2
Gapmin	1
Inacti	6
Iform	2

4. Create a Rigidwall in front of the bumper with given properties i.e. Dsrch = 1000 & Fric = 0.1

5. Use the ADMAS option to add mass at various points in the model, to bring the mass near to 700kg & CoG nearer to the driver as explained in the video

6. Apply Initial velocity along X axis of 15.65 mm/ms to the model

7. Set the Timestep to 0.0005ms and Tscale= 0.67 as explained in the video

8. Create cross sections at the respective locations as given in the Assignment question

9. Create Accelerometer at the base of the B pillar to plot the Accelerometer curves in the end

10. Delete the unnecessary joints in the model

11. Include all the Cross sections, Accelerometers, Rigidwall & Contact Interfaces in the TH

12. Check the model using Model Checker tool in HyperWorks as well as HyperCrash and make the necessary corrections.

13. Check for any Initial penetrations and make corrections if any

14. Run the Radioss tool and check the .OUT file for normal termination, Energy & Mass errors.

15. Plot the required graphs in HyperGraph & see the animation in Hyperview.

Results:

1. Output animation :

2. Sectional force in rails :

It can be observed that the Total Resultant force in both the rails i.e. the left & right is maximum at 10ms with a higher value in the Right rail(14.38kN) than in the Left rail(11.51kN).

3. Axial force received on Rails from Bumper :

It can be observed that the axial force received was maximum at 6ms (3kN).

4. Shotgun Cross-sectional Forces :

It can be observed that the plots for both the Shotguns i.e. Right and Left are almost identical with the maximum force being visible at 46ms in the Right shotgun (19kN) & at 48.5ms in the Left shotgun(19.26kN).

5. A pillar forces :

The maximum force of 6.95kN can be observed in the Right A pillar at 53ms, while the maximum force of 7.15kN can be observed in the Left A pillar at 50.5ms.

6. Acceleration curve :

It can be observed that initially the acceleration is very high on impact , but it decreases gradually.

7. Intrusions on Dashwall :

A. At node 66695 : The intrusion can be calculated as: Initial distance - Final distance = 767.575 - 492.6 = 274.975mm.

B. At node 66244 : The intrusion can be calculated as: Initial distance - Final distance = 781.808 - 529.802 = 252.006mm.

8. Energies :

The plot for various Energies is obtained as shown here:

Conclusion:

1. A few components in the model animation can be seen breaking away from the assembly due to the deletion of rigid bodies and spring elements connecting them to the surrounding components. (A few rigid bodies and spring elements had to be deleted to get a Normal Termination with 0 Errors and 0 Warnings).

2. Maximum forces were seen in the Shotgun and Rail Cross sections.