Frontal Crash Simulation Challenge

AIM:
To create a setup for frontal crash of car BIW and request for Time History plots.
OBJECTIVE:
1.Check unit system and either follow[Mg mm s] or [Kg mm ms].
2.Create appropriate interface ,friction 0.2 and recommended parameters.
3.Make sure of no penetrations and intersection.
4.Correct rigid bodies if any issues.
5.Create rigid wall with friction 0.1.
6.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.
7.Initial velocity 35 mph.
8.Use model checker to ensure good quality.
9.Time-step :0.5 to 0.1 microseconds.
10.Run 80 ms.
OUTPUT REQUESTS:
1.Sectional force in the rails at location of indicated node 174247.
2.Axial force received on the rails from bumper.
3.Shotgun cross sectional forces.
4.A pillar cross section.
5.Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
6.Intrusions on the dash wall 66695,66244.

THEORY:
1. A crash simulation is a virtual recreation of a destructive crash test of a car using a computer simulation on order to examine the level of safety of the car and its occupants.
2.It permits optimizaion of the design before a real prototype of the car has been manufactured. Using simulation problems can be solved.
3.The great flexibility of printed output and graphical display enables dessigners to solve some problems that would been nearly impossible without the help of a computer.
4.During a crash simulation the kinetic energy or energy of motion that a vehicle has before the impact is tranformed into deformation energy mostly by plastic deformation of the car body material at the end of impact.
5.Crash simulation are used to investigate the saftey of the car occupants during impacts on the front end structure of the car in a frontal impact.

PROCEDURE:
1.Import the given model.

CASE-1 (Check unit system and either follow[Mg mm s] or [Kg mm ms]):
1.Goto model browser > Cards > Begin Card > Check for the units.
2.The unit system followed in Kg-mm-ms.

CASE-2 (Create appropriate interface ,friction 0.2 and recommended parameters):
1.Type 7 contact is used with all recommended properties and with friction value of 0.2.
2.For Slave and Master all 74 components is selected.

CASE-3 (Make sure of no penetrations and intersection):
1.Goto Tools > Penetration Check > Select check types as intersections and Penetrions > Select all components > Check.
2.The output result is : All interface check is completed:0 collisions found.

CASE-4 (Correct rigid bodies if any issues):
1.As there is no penetrations and intersecions there is no isses with rigid bodies

CASE-5 (Create rigid wall with friction 0.1):
1.Goto Solver Deck > Right click > Rwall > plane.
2.Select any node on the bumper and change the x-coordinate such that a gap is maintained.
3.Say that the sliding friction with value of 0.1.

CASE -6 (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):
1.Check the mass and COG point.
2.Goto Tools > Mass Details > Mass,COG and Inertia.
3.Intial mass is 180kgs and cog point is not desirable.
4.Add mass to get 700 kgs and desirable COG point.
5.Goto Solverdeck > Right click > ADMAS > Select the nodes on which the mass should act > provide value of mass.

CASE-7 (Initial velocity 35 mph):
1. Goto Solverdeck > Right click > Create Inivel > Select all components and provide the value of velocity

CASE-8 (Time-step :0.5 to 0.1 microseconds):
1.Goto Model Browser > Cards > Anim_Dt > Tfreq = 5

CASE-9 (Run 80 ms):
1.Goto Model browser > Cards > Eng_Run > Tstop = 80.

OUTPUT REQUESTS:
CASE-1:
1.Creating frames at each cross-section where forces are to calculated.
2.Goto Solverdeck > Right click > Create Frame > Select N1,N2,N3 such that N1 and N2 are making X-axis and N3 X-Y plane.

3.Create section at which cross-sectional forces are to determined

3.Isolate the respextive co,ponenet and create the section by selecting the respective elements and choose the respective frame in the frame id and set iframe
= 12, the Cog of the section.
4.The same procedure is done for Rail component, Shotgun, Bumper Rail and A-Pillar region

CASE-2:
1.Create Accelerometer by right click in the model browser

2.Goto solver deck > ACCEL > Select the node and provide. Fcut = 1.9

CASE-3: (Intrusions on the Dash Wall 66695 , 6624)
1.Create the Skew on Seat connector frame on either end.

2.Goto Output block > Name it and select the node by node id.

For Intrusion 1:

For Intrusion 2:

CASE-4: (Model Checker):
1.We are using model checker to ensure good quality.
2.There are no errors in the model so we further move to next process simulation.
OUTPUT:
1.Goto Analysis > RADIOSS > Save the file > Include connectors > in Option -nt 4 > Prove the number of threads in options > Run.
2.The RADIOSS is run and it complete it job.
3.Open Hyper view >Import the h3d file.

1.THE VON-MISES STRESS:

2.THE DISPLACEMENT CONTOUR

4.The Energy Error, Mass Error, Internal, Kinetic Energy from 0.001_out file

5.The energy error is -1.1% and mass error is 0.03% which is acceptable.
6.The mass error is due to adding of mass for maintaing the time step value.
7.The maximum kinetic energy = 86970 J and Minimum Kinetic energy = 46560 J.
8.The maximum internal energy = 38140J and Minimum Internal energy = 146.5 J.
9.We can see at the start of simulation of internal energy is minimum and Kinetic energy is max.
10.As the deformation is taking place internal energy increases and kinetic energy decreases thereby maintaing the total energy as constant.

GRAPH:
1.Goto Hypergraph_2D > Import the T01 files.
2.Hourglass energy is less than 4% of total energy and is stablized by using the recommended properties.
3.We can see at the start of simulation the internal energy is minimum and K.E is max, as the deformation is taking place Internal energy increases and Kinetic
Energy decreases thereby maintaing the total energy as constant.

ACCELEROMETER:

On Shotgun Component

SECTIONAL FORCES ON THE BUMPER RAIL BRACKET

INTRUSION 66695 AND 66244:
1.66695:

2.66244:

OBSERVATION:
1.Thus the set up of a frontal crash test is performed.
2.Thus the create of a rigid wall, sectional forces is performed.
3.Thus the forces are distributed during the Frontal crash is performed.
4.Thus the Check energy, mass and momentum balance is performed.
RESULT:
1.Thus the graphical results were plotted for all test cases.
2.Thus the simulation it is observed that there is minimum of deformation in the cabin, and minimum intrusion was found in the drivers seat area.