Side Crash

OBJECTIVE:

To check and create the properties of a Neon Side Crash model using Hypercrash and to create the required output requests and verify the results for the same.

CASE SETUP & EXECUTION:

• Primarily the Hypercrash is opened and a proper unit system is chosen. Here, kN, mm,kg,ms unit system is chosen.
• The contact interfaces are checked for their recommended parameters. Also the type of contact interface given is also checked.
• The parameters for each interface is checked for correctness and it is changed to the recommended parameters.

TYPE 7 Contact Interface:

Istf = 4

Igap = 2

Idel = 2

Stfac = 2

Stmin = 1

Gapmin = 0.5

Inacti = 6

Fric = 0.2

Iform = 2

• The already created rigid bodies are checked if any errors are there in the model. Any issues with the rigid bodies are rectified. Here in this model there are no issues.
• Next a rigid wall is created with sliding with friction and the friction is set aas 0.1. Dsearch = 1000 and the diameter of the cylindrical wall is set to a standard value of 254mm.
• While creating the rigid wall, it is made sure that it does not penetrate into the elements or the nodes.
• An initial velocity is created for 35mph which is converted mm/ms that is around 15.64 in the Y-direction.
• The engine run file is made to run for 80ms.
• Next the timestep is maintained between 0.5 to 0.1 ms.
• After this mass balancing is done so that the total mass comes to 700kg. This is done my adding some mass on the mid-rails and cross members of the model.
• Then the output blocks are created. Two sections are created on the cross members of the model.
• For defining the cross sections, first the component on which the section needs to be created is selected. Then the base node is selected based on the node ID or a random node. After that the normal is defined.
• Intrusions at B Pillar, hinge pillar and fuel tank region is checked in the simulation. Differences in the crash or breaking is noted with respect to time.
• Peak velocity on the inner node of the door is also noted.

OUTPUT REQUESTS:

Sectional force in the cross members:

• In the first cross section nearly 5.5KN force is acting at 58ms and fluctuates to 2.1KN towards the end.
• In the second cross section 2.7KN force is acting at 33ms and stays around 2.5KN till the end.
• Here we can see that forces are less in the second mid-rail than the first mid-rail.

Intrusions at B-Pillar, Hinge Pillar and Fuel Tank region:

• Here in intrusion 1 we can see that the distance from the node 123428 is 1327mm and after the crash it has been reduced to 300mm.

• In intrusion 2, the node 123274 distance is 1311mm and after the crash it has been reduced to 450mm.

• The distance of 123321 has reduced from 1241mm to 800mm after the crash.
• Here in the animation we can see a significant amount of damage in the fuel tank region. This maybe due to material used has less stiffness.
• This can be avoided by using a material with hight stiffness and also the energy abosrbed can be higher in order to avoid more damage.

Peak velocity of inner node of the door:

• The peak velocity is nearly 16KN at the start and comes down to 3.8KN at 25ms.
• It increases to around 7.8KN at 40ms and fluctuates between 4KN and 6KN till 80ms.

Energy Curves:

Contact Energy:

• In the energy plot, we can see that the internal energy curve is increasing during crash.
• The kinetic energy is a measure of the internal energy. During the crash the K.E gets converted I.E which absorbs a considerable amount of energy.
• In this case less number of elements are deformed during crash.

RESULT & CONCLUSION:

Energy Error	Mass Error	Von Mises	Internal Energy
-1.4%	0.998E-02	0.3581 KN/mm2	20000

• The amount of energy absorbed is high. From this we can tell that the deformation can be controlled to a limit.
• The energy and mass errors are within the limit.
• The major amount of crash happens at the middle section of the car and the forces initially were high and seem to drop towards the end of the crash.
• The Von Mises is significantly less proving the safety of the car during the crash.

Hence the Neon Side Crash model was checked and analysed using Hypercrash, Radioss, Hyperview and Hypergraph.