NEON BIW SIDE CAR ANALYSIS USING HYPERMESH AND RADIOSS

Aim - Check and create the properties for a neon side crash model.

Objectives -

• 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.

Side impact crashes account for approximately twenty-six percent of all motor vehicle fatal crashes, second only to frontal crashes, according to a report by the National Highway Transportation and Safety Administration (NHTSA). While car companies and suppliers continue to develop new technologies that make vehicles safer, NHTSA rolled out updated safety regulations (FMVSS 214) based on new research studies, making vehicle safety design more and more complex.

The model is imported using Hypermesh, Then run model analysis to check for errors and warnings.

• There are free nodes and unwanted Springs attached in the model. Those are deleted.
• There are no penetrations and intersection in this model.
• Some contact interfaces are already defined for individual parts. But i would like to make this model with proper self-contact, so those defined contacts were also deleted.
• Now, the meshed model of neon BIW is ready for pre-processing. The unit system followed is KG KN mm ms.

Property card -

The shell property is edited according to the recomended parameters like ISHELL = 24 (QEPH SHELL FORMULATION) and ISOLID = 24 (HEPH with physical stabilisation) are assigned to reduce the hourglass effects on shells and solids.

Mass -

The distributed mass of 700Kgs is added over the rockers, rails and B-Pillar. These distributed mass are added using admas card in 1D panel. The added mass are assigned to move the COG of model to the middle and right next to the driver.

Initial velocity -

The Initial velocity of the model is 35MPh which is 15.65mm/ms. Because the whole model is in KG KN mm ms. The initial velocity is given for entire model in positive Y-axis direction for side impact.

Time step -

The Constant Nodal Time Step DT/NODA/CST of 0.0005ms and a Run time of about 80ms is set. The animation frequency is 5ms, so every 5ms it produces animation file as output. The nodal time step cost high run time but the result will be more accurate.

Sectional force -

The maximum resultant sectional force acting on the cross beam member 1 is 12.8 KN at 55ms at frame 12, and on the cross beam member 2 is 3.8KN at 21ms approximately.

Intrusion on B-Pillar -

The B-Pillar intrusion is taken at the node 124134 is 567.118 mm. The Individual intrusions are X= -3.938mm, Y = -566.346mm, Z= -29.317mm.

Intrusion on fuel tank region -

The Fuel tank intrusion have been measured at the node 123362 at time step 80 ms. The nodes are taken from the rails then the measure option is used to post process the results. The global intrusion observed is 974.471mm. The individual intrusion are X = -156.1131mm, Y = -301.980mm, Z = 61.602mm.

Intrusion on Hinge pillar -

The Hinge pillar intrusion have been measured at node 123322 at time step 80 ms at frame 17. The measure option used in hyperview to post process the result by graph. The global intrusion observed is 880.228322mm. The Individual intrusion are X = 209.043mm, Y = -823.619mm, Z = -133.955mm.

Method to reduce fuel tank intrusion -

• The underbody is the best way to reduce fuel tank intrusion. By adding another cross member it increases a weight of 5-10 kgs but it adds up some resistance during side crash.
• By replace the material of B-Pillar as Hot formed Ultra high strength steel can reduce the kinetic energy with great efforts.

Door plays a predominent role during side impact so if we use DSI - dynamic side impact beams we can decrease intrusions during crash. when we use aluminum alloy of composite beams we can reduce weight of beams as well as decrease the intrusion into the fuel tank region.

ENERGY GRAPH -

Energy error = -3.2%

Mass error = 0.4E^-4

Time Taken = 7878.54s

Number of cycles = 158896

Initially the system is in equilibrium and the internal energy is zero. The kinetic energy of the car is 85779.58 Joules, after the crash it reduces to 51628.74 Joules. therefore 31221.85 Joules is the maximum energy absorbed at 80ms.

RESULT -

• Internal Energy = 31197.58 Joules
• Energy Error = -3.2%
• Mass Error = 0.00004%
• cross member 1 sectional force = 12.8KN
• cross member 2 sectional force = 3.4KN
• Intrusion on B-PIllar = 567.118 mm
• Intrusion on Hinge pillar = 880.228322mm
• Intrusion on Fuel tank region = 974.471mm

References -

https://www.youtube.com/channel/UCRvT-aRk0ivhDHpO9HwBFxQ/videos

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwiejfOrrNzjAhUe6XMBHfjAA7MQFjABegQIDBAE&url=https%3A%2F%2Fwww-nrd.nhtsa.dot.gov%2Fpdf%2Fesv%2Fesv16%2F98s11o12.pdf&usg=AOvVaw23alKud7CIpXDQE4OyLr-H

http://ijsetr.org/wp-content/uploads/2015/12/IJSETR-VOL-4-ISSUE-12-4288-4293.pdf

https://www.sae.org/learn/content/c0717/

https://en.wikipedia.org/wiki/Crash_test