Assignment 6-Frontal Crash Simulation Challenge

Frontal Crash test

AIM:

Frontal car crash simulation of Dodge Neon BIW using RADIOSS solver and Preprocessing using HyperMesh / HyperCrash.

OBJECTIVE:

The following are the requirements for this project:

1. Set the model of the Neon Dodge ie, the FEA model, so that the required output requests can be post-processed from it. 
2. Sectional force in the rails at the location of indicated node 174247.
3. The axial force received on the rails from the bumper.
4. Shotgun cross-sectional forces.
5. A pillar cross-section.
6. Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
7. Intrusions on the dash wall 66695, 66244.

SETUP REQUESTS:

• Check the unit system and either follow [Mg mm s] or [Kg mm ms].
• Create an appropriate interface, friction 0.2, and recommended parameters.
• Make sure of no penetrations and intersections.
• Correct rigid bodies if any issues.
• Create a rigid wall with friction 0.1.
• Compare the model weight with the full-scale 300k nodes model and use added masses to reach the target weight of 700kg while getting CG about the required range.
• Initial velocity 35 mph.
• Use a model checker to ensure good quality.
• Time-step: 0.5 to 0.1 microseconds.
• Run 80 ms

OUTPUT REQUESTS:

• Sectional force in the rails at the location of indicated node 174247.
• The axial force received on the rails from the bumper.
• Shotgun cross-sectional forces.
• A pillar cross-section.
• Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
• Intrusions on the dash wall 66695, 66244.

Procedure:

Import the model:

Import the '.rad' starter file of the model,' neon_front_0000.rad' in Radioss using Import Solver Deck option.

Check unit system and either follow[Mg mm s] or [Kg mm ms].

Unit System:

For units, browse 

Model > Cards > BEGIN_CARD

Make sure of no penetrations and intersection.

for Intersection penetrations.

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.

To 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. Check by using Tools > Mass Details > Mass, cog and inertia and check the mass.

Existing weight of mesh geometry: 188 kg

Required weight : 700 kg

Additional mass to be added: 512 kg

To add additional weight to achive the required weight ,

Go to Solver and click on create select ADMAS create a new card now put the value of added mass 512kg & select grnd_ID as shown in below image.

following is the achived COG location,

Applying initial velocity:

solver > create > boundary conditions > inivel

the velocity need to be applied is 35Mph,

since, the units are kg mm ms , thefore the value to input is 15.65mm/ms

Create appropriate interface with recommended parameters and friction force is 0.2.

Once unit system is checked. Now we have to create appropriate interface.

Therefore, in order to create the interface of Type 7, we have to display solver browser by clicking

View---->Browsers---->HyperMesh---->Solver.

Once solver browser is displayed. Now we have to create appropriate interface i.e. Type 7 with recommended parameters as shown in picture below.

Solver---->INTER---->press right click on INTER---->Select create---->TYPE7.

A type7 contact is created between all the  72 components with friction coefficient as 0.2,

Rigid wall (wall):

To create a rigid wall at the front side of the car, creat the outermost node at the front of the car. Using temp nodes option.

Then right-click in
solver browser and navigate to Create >  RWALL > Plane

8. To apply timestep between 0.5 to 0.1 microsecond.

We have different methods to create time step such as INTER, NODA, BRICK, QUAD, SHELL, TRUSS, BEAM, SPRING etc.

And we have different time step control such as CST, CST1, CST2, DEL, STOP, AMS.

In this case we have created INTER and NODA as a type of time step control.

8.1. ENG_DT_INTER

This method is used in order to control the time step.

A type of time step option is “INTER” and time step control “DEL” is used.

We have to keep 0.67 as time scale factor and 0.0005 as a minimum time step control.

If time step gets reduced below the minimum time step, then this algorithm will add some mass to the element which leads to maintain time step more than minimum time step.

8.2. ENG_DT_NODA:

This method is used to control the time step from the nodes.

A type of time step option is “NODA” and time step control type “CST” is used.

In order to create ENG_DT_NODA we have to follow steps as explained below.

Change ENG_RUN to 80 ms

Go To Solver Tab > Cards > ENG_RUN > t.stop to 80 ms

To add a sectional force in the rails at location of indicated node 174247.

First we have to display the nodes i.e. 174247. In order to display the node, we have to follow:

Tool---->numbers---->By id---->Type node number---->Display---->on.

In order to create SECTION first we have to create the FRAME CARD. In this moving frame is attached with the nodes which is selected as origin.

Now, we have to create FRAME card in solver browser. In order to create FRAME card, we have to follow:

In order to assign parameters in FRAME---->MOV, we have to follow. In this we have to define origin node and then define the z-axis with second node which is in the direction of crash. And then we have to define the third node for plane as shown in picture below.

Once axis has created at node 174247, it will look like as shown in picture below.

Now we have to create the SECTIONAL force at RAIL_1. In order to create SECTIONAL force we have to follow:

First we have to create GRSHEL card by selecting elements as shown in picture below.

Now we have to assign this GRSHELL id in the SECT parameters as shown in picture below.

Now we have to give output blocks request in model browser as shown in picture below.

Shotgun cross sectional forces.

First we have to create a MOV collector in FRAME card as shown in picture below.

Now we have to assign GRSHELL id by selecting element as shown in picture below.

Now we have to assign parameters in SECT as shown in picture below.

Now we have to give output blocks request as shown below.

 To find sectional forces in A pillar.

First we have to create a MOV collector in FRAME card as shown in picture below.

Now we have to assign GRSHELL id by selecting element as shown in picture below.

Now we have to assign parameters in SECT as shown in picture below.

Now we have to give output blocks request as shown below.

To find acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).

First we have to create ACCEL card in solver browser as shown below.

Now we have to give output Blocks request as shown in picture below.

To add axial force received on the rail from bumper.

First we have to create a MOV collector in FRAME card as shown in picture below.

Now we have to assign parameters in SECT as shown in picture below.

Now we have to give output blocks request as shown below.

To calculate intrusions on the dash wall at node 66695 and 66244.