Assignment 6

ASSIGNMENT:6

OBJECTIVE:

Frontal crash-BIW

• Check unit system and either follow[Mg mm s] or [Kg mm ms].
• Create appropriate interface ,friction 0.2 and recommended parameters.
• Make sure of no penetrations and intersection.
• Correct rigid bodies if any issues.
• Create rigid wall with friction 0.1.
• 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.
• Initial velocity 35 mph.
• Use model checker to ensure good quality.
• Timestep :0.5 to 0.1 microseconds.
• Run 80ms.

Output requests:

• Sectional force in the rails at location of indicated node 174247.
• Axial force received on the rails from bumber.
• Shotgun cross sectional foces.
• 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:

1. Unit System used: [Kg mm ms].

1. Contact Interface:

I have deleted all previously irrelevant contact. Created new global contact which was type 7. In that select all components are master as well as slaves.

Type 7 contact:

3. Penetration and Intersection check:

There was no intersection and penetration in model.

4. Create rigid wall with friction 0.1

I have created rigid wall by Keeping D_search = 1000 and Fric = 0.1

I have tried creation rigid wall in hyper crash also.

5. 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.

Initial location of C.G. and weight:

I have added required weight to reach target weight 700 kg and C.G. on required range.

Achieved target weight 700 kg and C.G. location by adding mass on floor.

Now the mass created in hypercrash take as reference, and replicate same in hypermesh by selecting the proper nodes and areas.

6. Initial velocity 35 mph

Apply initial velocity to all nodes to 35 mph = 15.6464 mm/ms in X- direction.

7. Use model checker to ensure good quality

After clicking on Tool- Model checker-Radioss Block, get error and warning file. By right clicking and run file, I checked model quality.

8. Timestep: 0.5 to 0.1 microseconds

I have kept time step .0005 millisecond by editing ENG_DT_NODA card.

9. Run 80 ms

I have kept run time 80 millisecond by editing ENG_RUN card.

SECTION FORCE AND ACCELOMETER:

Below image show location of section forces at Rail, rails from bumper, shotgun and A pillar on both sides.

Below image show location of accelerometer at B pillar on both side.

Run model by clicking on radioss tab.

Check for energy error and mass error.

Max energy error = -1.8 % and Mass error = 0.0013

Output Requests:

• Von-mises Stress:

Maximum von-mises stress generated = 0.3564 GPa at 17 frame.

• Sectional force in the rails at location of indicated node 174247.

Max. Section force at left side of rail = 6.5 KN @ 25 to 30 ms.

Max. Section force at right side of rail = 3.5 KN @ 75 to 80 ms.

In left side of rail generate more force compare to right side of rail.

• Axial force received on the rails from bumber.

Max. Section force at left side of rail from bumper = 5.5 KN @ 25 to 30 ms.

Max. Section force at right side of rail from bumper = 3.6 KN @ 15 to 20 ms.

In left side of rail from bumper generate more force compare to right side of rail from bumper section.

• Shotgun cross sectional foces.

Max. Section force at left side of shotgun = 3.6 KN @ 65 to 70 ms.

Max. Section force at right side of shotgun = 2.25 KN @ 60 ms.

In left side of shotgun generate more force compare to right side of shotgun section.

• A pillar cross section.

Max. Section force at left side of hinge pillar = 2.75 KN @ 60 ms.

Max. Section force at right side of hinge pillar = 1.4 KN @ 20 to 25 ms.

In left side of hinge pillar generate more force compare to right side of hinge pillar section.

Max. Section force at left side of A pillar = 1.1 KN @ 65 to 70 ms.

Max. Section force at right side of A pillar = 0.5 KN @ 75 to 80 ms.

In left side of A pillar generate more force compare to right side of A pillar section.

• Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).

Max. Acceleration at right side of B pillar 8.5 mm/ms^2 @ 35 ms.

Max acceleration at right side of B pillar = 1.5 mm/ms^2 @ 70 ms.

In left side of B pillar generate more acceleration compare to right side of B pillar section.

• Intrusions on the dash wall 66695,66244.

Max. intrusion at node position 66451 of dash wall = 1100 @ 80 ms.

Max. intrusion at node position 66141 of dash wall = 1100 @ 80 ms.

CONCLUSION AND RESULT:

Find below table for value of section force, intrusion and acceleration.

Google drive link for model:

https://drive.google.com/open?id=1TOOZQmjxqUP-hC8yytYvtJiMlPjzmfS6