Side Pole Crash Simulation

AIM:

      1) To perform side pole crash for BIW model using radioss for the given parameters.   

• 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 penetration and intersections.
• Create rigid wall with friction 0.1 as per referance model.
• Compare the model weight with the referance model and use added masses to reach target weight 700kg while getting CG about the required range.
• Initial velocity as shown in picture.
• Use model checker to ensure good quality.
• Timestep :0.5 to 0.1 microseconds.
• Run 80ms.

      2) The following outputs should be obtained after the simulation.  

• Sectional force in the cross member.
• Intrusion at B pillar,hinge pillar and fuel tank region.Provide recommendation on what can help to reduce Fuel tank intrusion.
• Peak velocity of inner node of the door.

DESCRIPTION:

                       The results of a study on the response of a side impact beam located in a car door to impact loading is presented. The side impact beam is situated in both the front and rear side doors of a vehicle between the inner and outer shells to minimise intrusion into the passenger compartment during a collision whilst absorbing as much impact energy as possible. A numerical model of a light-weight passenger car, developed by the National Crash Analysis Center(NCAC) The resulting deformation of the door from the full vehicle model was used to design an experiment for an impact test on a passenger door to validate the simulation of an equivalent numerical model. Drop test experiments on beams with square and round cross-sections were carried out to validate the equivalent finite element model. The side impact beam was isolated for limited geometric optimisation with a view to improving the crashworthiness of the vehicle. The optimised compound tube configuration performed better than the single tube configuration in terms of SEA (specific energy absorbed) and maximum deflection.

PROCEDURE:

 Open the model in Hypercrash and select the unit system as [kg mm ms]

Then create Type-7 contact interface with the friction of 0.2 & follow the other recommended parameters.

We have to check penetrations & intersections before simulating the model. It indicates zero collisions.

For creating rigid wall follow the given parametrs diameter as 254 mm according to standards with sliding friction as 0.1 & search the distance of 1000

Then we has to create mass, Use add mass to add the masses on required points. The value of the mass should not exceed more than 700 kg as specificed.

We have to create initial velocity in the direction of y axis the value of 35 mph = 15.64mm/ms

 Then we have to create section in crossmembers as given in the model.

Before simulation we have to check warning & errors, if any occurs neglect them & run the model.

Then check the run time & time step values before simulating the model.

Go to analysis select radioss import the file & run the model.

Once the simulation is done, we are looking for energy & mass errors in the form of out file.

Mass error - 0.02458

Energy error -  -0.1%

Total no of cycles - 80001

Then import the model to Hyperview to find displacement & Von misses stress in simple average method.

Displacement:

Von misses:

Then plot the graph for internal, kinetic, contact, hour-glass & total energy by using Hypergraph-2D

In this process, we can absorbs that internal energy increases at the end of simulation. Hourglass energy remains constant. Contact energy slightly increases & remains constant. Total energy also remains constant.

Then Plot the cross sectional forces at cross members.

In this plot, the forces seems high at the beginning of the impact during run time of the cross members.

In this plot the intrusions are measured as displacement. One node is facing towards positive direction, Other two are facing in the negative direction. 

Then we are plotting the graph for peak velocity of inner side(node) of the door

The velocity values are observed, maximum peak velocity is 18.3941 mm/ms at the end of simulation velocity value is decreased upto 5.62 mm/ms

RESULTS:

•   Side pole crash model is set-up by the following parameters. Penetrations & Intersections are checked in the model.
•   Cylindrical rigid pole is created according to the standards.
•   Before simulating the model, model checker is used to observe wheather any errors & warnings are occured.
•   After the simulation is done, we have to check energy & mass error within the limits.
•   Then animations for von-misses & displacement is checked in Hyperview.
•   We have plotted graphs for energies, cross-sections, intrusions, velocity etc by using Hypergraph-2D