Assignment 7
OBJECTIVE: To perform frontal crash analysis on a Given 100k Node model in hypermesh after perfomring certain pre simulation checks.
SOFTWARE USED: Hypermesh RADIOSS and Hypercrash
PROCEDURE:
1. Load the file in hypermesh radioss workspace and import the solver deck file onto the workspace.
Figure 1: Imported Model
This is the model imported into the hypermesh workspace.
2. Now we need to perform some pre simulation checks.
a.
Check unit system and either follow[Mg mm s] or [Kg mm ms]
Figure 2: Units Assigned
b. Create appropriate interface ,friction 0.2 and recommended parameter
Figure 3: Conatact 1
Figure 4: Contact 2
c. Penetration check
Figure 5: No Penetrations
d. Rigid Wall Creation
Figure 6: Rigid Wall Creation
e. Perfrom mass balancing to achieve 700 kg weight with proper CG of the vehicle
Figure 7: Mass 700 Kg
Figure 8: Mass Balanced CG display
f. Initial Velocity
Figure 9: Initial Velocity
g. Runtime change
Figure 10: Runtime Change
h. Model Check
Figure 11: Model Checker errors to zero
For the Output requests we have to log some output blocks and then assign the nodal velocities as given in the requirements for the crash.
Figure 12: Output blocks
After all these checks we now will run the simulation
RESULTS
After a successfull run of the RADIOSS Solver, We get the following readings for energy and mass error. The program also terminated normally.
Figure 13: Mess and Energy Error
Figure 14: Internal and Kinetic Energy
We can see that the internal and kinetic energy will coincide at a point which will be after 80 ms. We can clearly observe that the kinetic energy starts at a higher value due to velocity attained at 15.64 m/s and then gradually decreases as the crash takes place. Similarly internal energy first is at zero but as the velocity increases the elements stiffen up during crash and thus internal energy increases.
Figure 15: Force at cross member 1
We can see by the above figure that the section forces acting at the right rail.
The maximum force at the point is 6.96 KN at 16 ms.
Figure 16: Forces on cross memeber 2
We can see from the above figure that the forces at left rail rach upto 9 kN at a max time of 18 ms.
Figure 17: Cross Members
From the simulation results we can infer that the cross member 1 deformed less in the process as it has been provided with a support.
Figure 18: Intrution at Hinge Pillar
Figure 19: B-Pillar Intrusion
Figure 20: Fuel Tank Intrusion
We also have performed the peak velocity at a particular node.
Figure 21: Velocity peak at the given node in the challenge
For a standard crash simulation, Peak velocity is an important because the driver compartment also has the same velocity. We can see that the peak velocity was 15.64 at the start and then gradually came to be zero and then changed its values as the simulation went through.
Figure 22: Contact Energy Plot
Figure 23: Von Misses Stress
The Maximum value of Von Mises Stress reached is 329 Mpa.
Figure 24: Max Value of Von Mises Stress
CONCLUTIONS:
The following Values are Obtained from the simulation
Max force for a cross-section in cross member-1 = 6.92 KN
Max force for a cross-section in cross member-2 = 9 KN
Displacement of hinge pillar node 123555 =566.845 mm
Displacement of B- pillar node 123146 =913.069 mm
Displacement of Fuel Tank node 123093 =964.933 mm
Peak Velocity of node 337773 =15.65 mm/ ms2
Maximum VonMises Stress = 329 Mpa
Maximum Plastic Strain = 1.050
We also Conclude that to prevent more deformation of the parts we added more mass so that the CG also remained balanced and material properties play an important role in crash testing. We can also conclude that due to high impact forces, side of the vehicle is damages more.
The Link for the Files is : https://drive.google.com/drive/folders/1x4XuQNQpfEkXdXx1wjmcWAq2MrZSTvNC?usp=sharing