Challenge

Assignment 6-Frontal Crash Simulation Challenge

KKuruba Dileep Kumar18 Jun 2022

AIM:- To perform the frontal crash analysis on the BIW part of the car using the hypermesh and Solving with the Radioss and to check where the stresses are acting on it.

OBJECTIVE:-

Check the unit system and change the unit system if necessary.
Check appropriate interface and recommended properties and friction value of 0.2.
To check the penetrations and intersections between the components.
Correction of rigid bodies if any issues were found
Create a rigid wall with the friction of 0.1
Compare the model weight with the full-scale 300k nodes model and use added masses to reach the target weight of 700 kg while getting CG about the required range.
Give an initial velocity of 35 mph
Use a model checker to ensure good quality.
Give the time step 0.5 to 0.1 microseconds.
Give run time to 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:-

First we have to open the 0000.rad file in the text editor or notepad to check the unit system used in the file.

Unit system checking

The unit system used is kg-mm-ms, the recommended unit system for the analysis.
Firstly, we have to import the model file into the HyperWorks as a slover deck
we can import the file by >>import>>import slover deck>>choose the 0000.rad file and then import the file.
We can check the unit system of the imported file by begin card. >>Model>>cards>>begin_card

Once the unit system is checked, Now we have to create a proper interface with recommended properties and friction =0.2
We can create the interface of the file by >>view>>hypermesh>>slover>>right click and create the type 7 interface

Type 7 interface is created with recommended properties

For smooth simulation of the model, there should not be any penetrations and interfaces. In order to check the penetrations, we have to follow >>Tools>>penetration check>>select group>>check

Penetration check

There are zero penetrations and interfaces were found in the model.
Now we have to create a rigid wall with the friction of 0.1 between the car and the rigid wall.
For this, >>slover>>click right click>>create>>RWALL>>plane

creating the rigid wall

To make a rigid wall we have to create a reference node. First, we will create a temporary node in the middle of the bumper. after that, we will translate that node to create a gap between the wall and the car as shown in the image

translating the node

enter the friction value as 0.1 and Dsearch as 1000 and create a rigid wall

creating the rigid wall

Now we have to 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.
For this, >>Tools>>mass details >>mass COG and inertia.

Interface for mass checking

Therefore, in this model, we have a total mass of the value approximately equal to 188.02 kg as shown in the below figure. But in the given 300k nodes full model we have a target mass of 700m kg.

Therefore, in order to create the mass. First, we have to select the nodes by creating GRNOD. In order to create the masses on the nodes, we have to create GRNOD by >>Slover>>create>>GRNOD>>nodes and select the nodes

Creating the GRNOD

Now we have to add masses to increase the overall weight of the car by assigning GRNOD ID by >>Slover >>Create>>ADMAS.

Interface for ADMAS

Now in the add mass card, we have to give the GRNOD ID and the respective target mass.

Adding mass to the ADMAS card

Now, we have to check the mass card again to check the target mass and CoG

Mass and CoG of the model

Now we have to create an initial velocity of 35mph for the model.
For creating the initial velocity we have to follow >> slover>>create>>boundary conditions>>INIVEL

Boundary conditions interface

Now we have to create the GRNOD id by selecting all components as entity id as discussed in the above step.

GRNOD with all components is created

And we have to provide the initial velocity as 35 mph (15.65 mm/sec) in the INIVEL card in translational X-direction and the remaining two directions will be constrained.

Now we have to check the quality for smooth simulation
First I will import the model into the hypercrash application then I will move to hypermesh for further simulation
we can open hypercrash >>Applications>>hypercrash>>select appropriate unit system >>run

Opening hyper crash

We will use hypercrash to run the model checker. In order to switch the model from HyperWorks to the hypercrash

we can import the file by >>File>>import>>RADIOSS>>choose file path, then import

Imported file

We can check the quality of the model by >>Quality>>model checker>>Run

Model checker interface

After clicking the Run we will get the report as shown below

Quality check report

Now we have to apply the Time-step value of 0.5 to 0.1 microseconds.
we have different methods to create time steps such as INTER, NODA, BRICK, etc and we have a different time step control such as CST, CST1, DEL, etc.
In this case, we have created INTER and NODA as time step control.

(I) ENG_DT_INTER

This method is used to create a time step control
we have to keep 0.67 as the time scale factor and the time step control as 0.0005.
We can change the values as shown below

(II) ENG_DT_NODA

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

We have to give a run time of 80 ms

OUTPUT REQUESTS

(I) Sectional force in the rails at the location of indicated node 174247

First, we have to display the required node by >>tools>>by numbers >>By id >>type node number >>display>>on
In order to create section we have to first create Frame card. In order to create frame card we have to follow the order as shown in the below figure.

In order to assign the parameters in the FRAME CARD, we have to define origin node and then define z-axis with second node which is in the direction of crash and Third node for plane as shown below

Once axis is created at node it looks like this

Now we have to create sectional force at rail 1 . The sectional force can be created as shown in below figure

Now we have to crete GRSHEL card by selecting elements as shown

Now we have to assign GRSHELL id in SECT parameters as shown below

Now we have to give output block requests in the model browser as shown in the image

(ii)Axial force received on the rails from bumper.

For this, first we have to create MOV in frame card

Now we have to assign the parameters in SECT card

Give output resquset on model browser as discussed in above step

(iii)Shotgun cross sectional forces.

For this, first we have to create MOV in frame card

Now we have to assign GRSHELL id by selecting our focused element as shown in figure

Now we have to assign the parameters in SECT card

Now we have to create a output request block

(iv) Sectional forces in A pillar cross section.

For this, first we have to create MOV in frame card

Now we have assign GRSHELL id by selecting the elements as shown

Now we have to assign the parameters in SECT card

Now we have to create a output request block

(v)Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).

For this, first we have to create ACCEL card in the slover browser

Interface

Now, we have assign the accelerometers parameters as base of B-piller

Now we have to create a output request block

(VI)Intrusions on the dash wall 66695,66244.

In order to show the nodes we have to follow, we have to display the required node by >>tools>>by numbers >>By id >>type node number >>display>>on

Now create a SKEW card for both the nodes.

creating skew card

Now, Create Time histroty of Nodes as shown .

interface of time history of node

Creating Time history of nodes

Now we have to create a output request block for both the nodes

Final model

SIMULATION OF FRONTAL CRASH ANALYSIS

we can run the simulation >>analysis>>radioss
we have to save the in the new folder to store all output files. In the options tab, we have to recommend keeping "-nt4" which indicates 4 crores to run the simulation faster. where "nt" indicates a number of threads.

After clicking Radioss, the analysis window pops up and we can see after a few minutes the job was done successfully

The simulation is done, now we have to visualize it in hyper view. for this we have to open hyper view and import the .h3d file.
and opening contour, then select von misses and averaging method as a simple average method.

In the next step, we have to carry out the energy and mass error analysis. For this, we have to 0001.out file in the notepad. Scrolling to the end we can see the energy error and mass error

The final energy is -2.0%, which is very acceptable, and the mass error is 0.4109E-01
Now we have to plot the graphs in the hypergraph tool and in hypergraph we have to import the.T01 file.

CONCLUSIONS:

Simulation was done successfully on the given BIW model as per the given conditions.
All the output requests have be calculated and plotted such as sectional forces, axial forces acceleration and intrusion of the dashed wall
From the simulation results we can conclude that there was a minimum deflection in the cabin
Minimum intrusion is observed at the driver seat

Assignment 6-Frontal Crash Simulation Challenge

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.