Assignment 6-Frontal Crash Simulation Challenge

Objective:

To perform the frontal crash on the given model within the given parameters.

Frontal crash-BIW

• Check 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 intersection.
• 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:

• Open the hypermesh software and select the profile as Radioss.
• Import the given model with the help of an option Import Solver deck present at the top in the menu bar.
• After importing the model start working on the model within the given parameters.
• open the hyper crash application from the hypermesh software and check the unit system.
• The unit system used Hypercrash is KN MM MS KG
• Upon opening the hyper crash application import the same model which have been imported into the hypermesh software.
• After opening the given model in both the applications try to work on the model.
• In Hypermesh, create a rigid wall for the given model by using the solver browser, In the solver browser, right-click and select CREATE and from the options select the RWALL which is at the bottom and select the PLANE type.
• After creating a Rigid wall, click on it & in the status bar enter the details of various parameters and select the node where we should need the Rigid wall and after entering all the values the RWALL is created on the graphic area. Check on the created RWALL and make corrections if needed.

RIGID WALL CREATED FOR THE MODEL

• Create a INIVEL card which means an initial velocity is given for the model. In the solver browser, right-click and select the create and from the options select the boundary conditions at the top and from the list select the INIVEL card.
• After creating the INIVEL card select the card in the solver browser and in the status bar enter the details of various parameters like Vx, Vy, Vz and select the whole components. In the Vx, this means velocity in the x-direction enter the value as 15.64 and in the rest of the directions keep it as o which means in Vy and Vz.
• Scroll down in the status bar, in the Grnod_id option, select and right-click and select the create option and a window will pop up in the graphic area in that select the option called entity id in that change the option from nodes to components with the help of dropdown options and select all the 72 components on the screen and click OK and close the window.

INIVEL CARD CREATED FOR THE MODEL

• Create two Accelerometers for the model on the rocker on both sides, in the solver browser right-click and select the create and from the options select the ACCEL card an accelerometer 1 is created. Before creating the ACCEL card create a Skew on both sides.
• To create a Skew on both sides, in the solver browser right-click and select the create option and scroll down to the bottom and select the SKEW card in that select the MOVING SKEW. Select the SKEW card and down in the panel area to select the option Create by node reference and select the origin node first and then select the node for the X-axis and then select the node for XY plane overall select the 3 nodes in order to create a SKEW which means a coordinate system.
• After creating the SKEW card go back to accelerometer 1 that has been created and in the status bar select the NODE_Id and click on the origin node which we selected for the skew and for the SKEW select the coordinate system which we have created which means SKEW. Enter the F_cut value as 1.64. Repeat the same process for Accelerometer2 for the Rocker-B on the other side. First by creating a SKEW and by selecting a NODE_Id followed by selecting a system and by giving the F_cut value.

ACCELEROMETERS CREATED FOR THE MODEL

• Create an Output Block in the model browser and name it Accelerometer, select the Output block and in the status bar select the two accelerometers and assign them to the Output Block.

OUTPUT BLOCK FOR THE ACCELEROMETERS IN THE MODEL BROWSER

• Create Intrusions on the dash wall 66695,66244. Firstly, click on the model browser, right-click and create output-blocks and name it spring 66695 and also create another output-block and name it spring 66695.

OUTPUT BLOCK FOR INTRUSION 1 AND 2

• Before defining the intrusions create two skew cards for the intrusions in the same way we created for accelerometers. Click on Intrusion-1, in the status bar select the ENTITY_id option and click on the node and select the node by entering the id which is 66695 and select the skew and select the coordinate system which we have created on the cross beam which is on the middle of the floor panel. Repeat the same process for the Intrusion-2.

INTRUSIONS SPRINGS ON THE GIVEN MODEL

• After creating the intrusions, create a Type 7 interface for the model in the solver browser. In the solver browser, right-click and select the create from the list of options select the INTER and in that select the TYPE 7 Interface. Click on the Type 7 Interface in the solver browser, and in the status bar enter the recommended values for various parameters and also select the slave and master entities. After creating the type 7 interface, delete the various other interfaces which are of no use.

ALL THE COMPONENTS SELECTED FOR THE TYPE 7 INTERFACE

• Add the mass to the given model, the mass value given for the model is 700kg. To add the mass in the solver browser select the add mass card and right-click and click on the Create for a new add mass card.
• After creating an Add mass card, select the newly created add mass card in the solver browser. In the status bar, enter the value of mass in the Mass option as 1KG and select the option MassType and select the first option and in the grnd_ID option select and right-click and in the Entity ID select the nodes by using box selection on the floor panel. Select the no of nodes needed to attain the 700kg mass. After selecting the nodes click on the close button to close the subwindow.
• Make sure to bring the COG point to the centre of the cross beam in order to maintain the balance.
• After adding the mass to the model, create the cross-sections on the model which are given with the question.

MASS HAS BEEN ADDED UPTO 700 KG

• Create a sectional force for the A-pillar, to create a section in the solver browser right-click and select the create option and scroll down to the bottom and select the SECT card. After creating the SECT card and rename it as A-pillar.

A-PILLAR SECTION ON THE MODEL

• Before doing all this, create a FRAME for the cross-section in the same way as we created the SKEW.
• After creating the FRAME select the A-pillar cross-section and in the status bar enter the details for the various parameters and in the GRSHELL Id select two rows of elements on the A-pillar and in the Iframe select option- 12 the COG of the section.
• In a similar way, create section forces for Shotgun, Bumper and Rails. Create section forces for the same 4 components on the other side this means for the B-pillar, Shotgun-B, Rail-B and for Bumper-B.

ALL THE 8 CROSS SECTIONS ON THE MODEL

• After creating all this, create an Output Block in the model browser and name it as Cross-sections. Select the Output Block and in the status bar assign all the 8 cross-sections in the Output Block.

OUTPUT BLOCK FOR THE CROSS SECTIONS

• After creating all this, export the file to a folder on the computer. Import the exported file to the Hypercrash application. After importing the file, click on the Quality on the top of the window and select the model checker from the given options.
• In the model checker browser, it shows some errors and warnings for the model, clear the errors manually one by one. After clearing the errors export the file and to the specified folder by using the file option at the top of menu and click export in that and select the Radioss option, a pop window will appear on the screen in order to export the model select the folder you want to export the model and click on the OK button.

ERRORS AND WARNINGS SHOWN IN THE MODEL CHECKER IN THE HYPER CRASH APPLICATION

• After Exporting the model to a specified folder, import the model in the Hypermesh application and run the model. Click on the Analysis on the tool panel and select the Radioss tool from the available tools.
• After entering into the Radioss tool, select a specific folder to save the model and check in the options enter the value as -nt 4, click on the include connectors option and after selecting all these options click on the Radioss button to run the simulation.

• After running the model open the Hyperview application to look at the simulation of the model. By using the load model option select the .h3d file from the results.
• After opening the neon front.h3d file, click on the Apply button present in the bottom corner in order to view the simulation.

NEON_FRONT MODEL SIMULATION IN THE HYPERVIEW APPLICATION

• and the energy error is -2.7% and the total number of cycles is391668. From the results obtained we can conclude that the crash phenomena is acceptable.

THE MASS ERROR AND ENERGY ERROR FROM THE.OUT FILE

• After looking at the simulation open the HyperGraph application in order to plot the Results of various energy parameters.

• Open the HyperGraph application, in the Data file option click on the file icon, select and open the neon_frontT01 file present in the saved folder during the analysis in the hypermesh in order to plot the results.

• In the X type subcase select the Time, in the Y type subcase select the Global Variables, in the Y request select the Internal energy and in the Y component select the MAG option and then click on the apply button.

• In the above-plotted graph, there is Total energy which raised up to 87000 joules and stays constant towards the end of the simulation.

• Internal energy is increased from 0 to a value of 53000 joules from the start of the simulation to the end of the simulation.

• Contact energy and Hourglass energy are the same from start to end of the simulation.

• In the same way, plot the remaining energy parameters for all the cases and compare the results.

• Plot the section forces for the following cross-sections created on the model.

The sectional force on the RAIL on the location indicated node is 174247. The force acting on the RAIL is more important because it determines the rigidity of the vehicle.

The total resultant force acting on the rail reaches a peak in the middle of the simulation at 45ms

• The Axial force received on the rails from the bumper

• Shotgun forces cross-sectional forces. The shotgun structure is made stiffer in a way during a crash the passengers in the front seats don't have to face a rigid body thrashing against the leg.

• A-pillar cross-section forces. Based on the graph the A-pillar is of less stiffness and the deformation is so large.

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

The Acceleration experienced is high at the start of the simulation and it reaches low at the end of the simulation. The passengers inside the rear seats experience less compared to the front during the crash. The Acceleration on the X-direction is plotted.

• Intrusions on the dash wall 66695 and 66244.

The displacement caused on the nodes where the dash wall is located is calculated.

Conclusion:

• The initial velocity applied to the car body in the X-direction is 15.7mm/ms.
• The errors obtained in the model checker are cleared manually in the Hypercrash.
• The output requests which are given in the question are created and the cross-sections have been plotted in the HyperGraph application.
• The mass and energy error has been taken out from the .out file and the values are obtained from the simulation are in an acceptable range. The is a steady increase in mass and energy error values.

Link for report:

https://docs.google.com/document/d/1MYPtoNTWhFPMcKghY35suJn1gWsFXgQEdEgY3GyJjKE/edit?usp=sharing