Assignment 7-Side Pole Crash Simulation Challenge

 

Assignment: - 7.  Side Pole Crash Simulation

Aim:

To run a simulation for the Neon Side Pole Crash and to obtain the results in the post-processing.

Objective:

To check the unit system in the solver.

To create an appropriate interface with friction 0.2 and recommended parameters.

To check for the penetrations and intersections in the component.

To create a cylindrical rigid wall with the friction of 0.1.

To add extra mass to attain a target mass of 700 kg.

To apply initial velocity to the car.

Keep the min time step of 0.1micro sec & max of 0.5micro sec.

Run the model up to 80 milliseconds.

To find the sectional force in the Cross member.

To calculate the intrusions at the B-pillar, Hinge pillar, and at Fuel tank region.

To calculate the peak velocity of an inner node of the door.

To request TH for all the inputs created.

To run the simulation.

To plot the graphs in the post-processing.

[Note: According to FMVSS [Federal Motor Vehicle Safety Standards]. Assign a initial velocity of 20mph,1mph=0.44704 m/s,=20x0.4470,=8.94 m/s.]

Procedure:

Phase 1-Check unit system and either follow [Mg mm s] or [Kg mm ms].

To import the model, Go to Standard Panel >> Import >> Import Solver Deck.

Import Solver Deck option should be selected to import the radioss starter file.

 

 

Now go and check for the unit system of the model, to check for the unit system, go to the Model Browser >> Control Cards >> BEGIN_CARD.

Check for the unit system

Now go to the HyperCrash, to go, Go to Menu Bar >> Applications >> HyperCrash

Make sure whether the unit system in HyperCrash is [ kN, kg, mm, Ms].

Now import the model in HyperCrash import the model, Go to Menu Bar >> File >> Import >> Radioss.

Here select the appropriate Radioss File and import the model into HyperCrash.

Phase 2-Mass Balancing [ Adding Mass to the Model to get COG at Proper Position]:

Here the COG is not in a proper position. so, we need to add mass to get COG at the proper position, it’s like balancing.

To Check the Mass and COG [Centre of Gravity], go to HyperCrash Menu Bar >> Mass >> Balancing

 

After hitting on the spec’s icon. The initial position of COG will appear.

Now mass should be added to get COG in a proper position. it should be in the center of the cross member.

To bring COG to the centre of the cross member, we should add a mass.

To add mass, Go to Load Case >> Added Mass.

 

Now right click on the added mass browser and select Type=1, Mass is distributed to each node of the node group.

 

The initial mass is 166 so we have to add 534 masses.

 

COG after providing mass.

Now export this file and save it in a specified location and import this model into hypermesh and check the total mass.

Now import the exported model from HyperCrash to the HyperMesh.

 

 

 

Next, go and check in hypermesh, Whether we have attained 700 kg mass.

To check, Go to Menu Bar >> Tools >> Mass Details >> Mass, COG, Inertia

 

Phase 3-Create the Interfaces

Here for this model, TYPE 7 Contact Interface is created with the recommended parameters.

Phase 4 -Check for the Penetration

Here check for the penetrations, to check, Go to Menu Bar >> Tools >> Penetration Check.

 

 

Phase 5-Creation of Section at Cross Member :

Here we have to create a section, the section should be created at the cross member.

Next for creating a section, we need a frame, so we need to create a frame first. To create frame Right-click on the Solver Browser >> Create >> Frame >> Mov.

 

 

Next, select the nodes to specify the location of the frame to be created on the model.

Switch to the created by node reference, Now selects the Node at Origin >> Node at Z-axis >> Node at YZ Plane,

 

Then create a section, to create a section, Right Click on the Solver Browser >> SECT >> SECT.

After selecting the SECT to create a section, A parameter window will be opened left side.

There will be Nodes (N1, N2, N3), Select the nodes to create a section

Next Right Click on the grshell_id to select the elements, where we created the section.

Enter the values for deltaT and alpha.

Coefficient of filtering (alpha=0.67).

Time step for saving the data (deltaT=0.001).

 

 

Now we have to check whether the section created for the rail component is fine or not fine.

If all the nodes get realized in the elements, then the section created for the rail component is fine.

One row of elements should be maintained.

To check Right-click on the Section in the Model Browser >> Review.

Similarly, we have to create another two sections in the other cross member

 

 

 

 

Phase 6-Creation of Intrusion at B-Pillar, Hinge Pillar and Fuel Tank Region:

Here we have to create intrusions at B-Pillar, Hinge Pillar and Fuel Tank Region.

First, we have to create a spring 1D element, to create, First create a temp node on the B-Pillar base component.

The next step is translating this node to another left B-Pillar, Cause to create a spring, we need two nodes, so translate the node and create a temp node parallel to the, where the node created on the right side of the B-pillar, Create a temp node with the reference of translated node.

Temp Node Created on the Left Side of B-Pillar with the help of Node Translated from Right Side of B-Pillar.

Now create a spring, to create a spring element, go to 1D >> Spring >> Select Node 1 and Node 2.

Created 1D Spring Elements at B-Pillar Region, Hinge Pillar region, Fuel Tank Region.

 

 

The next one is to assign the mass and stiffness values for the created springs, in the parameter region.

Phase 7-Create Initial Velocity:

Now we have to give the initial velocity to the car.

So, to give the initial velocity we have to create INIVEL.

To Create, Go to Solver Browser >> Right Click >> Create >> Boundary Conditions >> INIVEL.

 

 

So, we want the car body to move in the x-direction so we have to give the velocity in the x-direction only.

We need to give the velocity as 20 mph which we have to convert into the m/s. so after converting the velocity we got the velocity as 8.94 m/s.

 

Phase 8-Create Peak Velocity of Inner Node of the Door:

Here we have to create a peak velocity, to create a peak velocity, first, we have to create a node.

We have to give peak velocity at the given node [337773].

To find the node, Go to Display Panel. To find we have to display the numbers in the display panel.

Select the node by id and enter the id number and click on it. The node number will be displayed, we have to create a node there and request TH for that node.

 

Next, Create a TH for that node. Because to know the peak velocity at that point.

So, we have to request TH for that Node. To create a TH for that node, Right Click on the Solver Browser >> Create >> TH >>NODE.

 

 

Phase 9-Create rigid wall with friction 0.1:

Here we have to create a cylindrical rigid wall, Cause this side pole crashed, 

To create Rigid Wall, Right Click on Solver Browser >> Create >> RWALL >> CYL.

Next, we have to create a temp node on the car door to make a cylindrical rigid wall.

After creating a temp node, Translate that node to 300 mm.

After translating a node, In the RWALL parameter window, we have to select (XM, YM, ZM). It is selected by, clicking on the node which was translated which is shown below.

And the few parameters such as Friction, the diameter of the cylindrical pole (Rigid), Searching tolerance (Dsearch) should be given which are shown below Figure.

 

 

Phase 10-Request TH File for the Required Outputs and Give Time Step Value:

Here the timestep should be assigned to the model to run the simulation.

The required values to be entered in the ENG_DT_BRICK, ENG_DT_INTER, ENG_DT_NODA control cards

 

 

 

 

 

Next, the TH should be requested for the Interfaces, Sections, and Intrusions [Springs].

TH for Interface:

Second request TH for the Interface, to request TH Interface, Right Click on the Solver Browser >> Create >> TH >> INTER

 

Next at the bottom, there will be a window, there go to the Entity IDs option and select the groups, A window will pop up, select all and hit on ok.

 

TH for the Sections:

Similarly, create the TH for sections as created for the previous case.

TH for the Intrusions (Springs):

Similarly, create the TH for Springs as created for the previous case.

 

 

Phase 11-Checks:

Finally, after doing all the load case setup, we have to check for the errors, and whether every load case setup is fine or not.

To check, Go to Tools >> Model Checker >> Radioss Block.

Next, the model checker window will be open.

There right-click on the browser and click run or hit on the green checkmark in the window.

Phase 11-Run the Simulation:

Now run the simulation, to run the simulation, Go to Analysis Panel.

Go to Analysis Panel >> Radioss >> Select the Input File >> Save it in Different Folder and Rename it as Test-1 >> Run.

Check the Include Connectors, if there are any connectors in the model, The connectors will also be taken into account.

Type -NT 4 in the options tab, this will make the simulation faster.

Where NT indicates No of threads,4 indicates assigning the task to 4 cores in the system.

After completing the simulation, the radioss will pop up a solver window stating Radioss Job Completed which indicates the simulation has been completed.

Now go and open the 0001.out the file with notepad.

The obtained values for Energy Error, Mass Error, Internal Energy Error, Kinetic Energy Error, and Contact Energy Error have been shown below.

HyperView allows for loading and viewing result files obtained from several sources.

Based on the solver type of the files and the results you would like to visualize and analyze, there are different ways to load the input deck and their corresponding results into HyperView.

First, begin the postprocessing in the Hypermesh.

Import the animation file .h3d into the HyperView.

Load the .h3d file.

Then select apply.

After importing the .h3d file into the GUI, Enable the contour.

The contour tool creates contour plots of a model graphically visualize the analysis results.

To enable contour, Go to Results Toolbar >> Contour.

Now switch to the Von Misses Stress in result type and select the component, select the averaging method as simple and then click apply.

 

Check for the Intrusions:

After running the simulation, we have to check for the intrusions.

Note: The allowable intrusion is 15 cm.

To check for the intrusion, Measure the distance between the springs where we created.

To measure, Go to the Measure tool from HyperView and select the end node of the springs to know the distance between them.

The Intrusion at Fuel Tank Region:

After defining the nodes at the end of the spring at the initial position before the collision, the magnitude for the spring at node 33112 is 1404.784 mm.

After defining the nodes at the end of the spring after the collision, the magnitude for the spring at node 33112 is 1405.871 mm.

Intrusion [Spring] at Fuel Tank Region is 1404.784-1405.871= -1.09 mm.

Intrusion at B-Pillar Region:

After defining the nodes at the end of the spring at the initial position before the collision, the magnitude for the spring at node 123609 is 1335.034 mm.

After defining the nodes at the end of the spring after the collision, the magnitude for the spring at the node 123609 is 1000.486 mm.

Intrusion [Spring] at B-Pillar Region is 1335.034-1000.486 = 334.548 mm.

Intrusion at Hinge-Pillar Region:

 

After defining the nodes at the end of the spring at the initial position before the collision, the magnitude for the spring at the node 1276 is 1329.375 mm.

After defining the nodes at the end of the spring after the collision, the magnitude for the spring at the node 1276 is 1309.023 mm.

Intrusion [Spring] at B-Pillar Region is 1329.375 – 1309.023 = 20.352 mm.

2) Plot the graphs using -Hypergraph 2D:

Now plot the graphs using Hypergraph 2D, we are plotting the graphs to see what is happening in the rail component.

Hypergraph 2D is a powerful data analysis and plotting tool with interfaces to many popular file formats.

It is a sophisticated math engine capable of processing even the most complex mathematical expressions.

Hypergraph 2D combines these features with high-quality presentation output and customization capabilities to create a complete data analysis system for any organization.

To plot the graph, Go to Hypergraph 2D >> Data File >>side_pole_crashT01 >> Apply.

 

Intrusion Graph for Fuel Tank Region:

Here the graph is obtained for the Fuel Tank region.

In the beginning, the length of the spring was 1404.784 mm and after when the car crashed the pole, the length of the spring is 1405.871 mm. So, the total deflection of the spring is -1.09 mm.

Intrusion Graph for B-Pillar Region:

Here the graph is obtained for the B-Pillar region.

In the beginning, the length of the spring was 1335.034 mm and after when the car crashed the pole, the length of the spring is 1000.486 mm. So, the total deflection of this spring is 334.548 mm.

Intrusion Graph for Hinge-Pillar Region:

Here the graph is obtained for the Hinge-Pillar region.

In the beginning, the length of the spring was 1329.375 mm and after when the car crashed the pole, the length of the spring is 1309.023 mm. So, the total deflection of this spring is 20.352 mm.

Peak Velocity:

When the car hits the pole, the door will be deformed, so due to the deformation, the inner portion of the door will hit the passengers inside the car and it may cause severe injuries to the passengers. So, it is important to calculate the peak velocity at the door region. The peak velocity of the node on the door is 9.3506 m/s. The graph is in Zig-Zag form, Due to the noise and vibration, When the car hits the pole. Here the velocity is starting from the peak due to the initial velocity is given and it goes on decreasing, causing the car to go and hit the pole, due to deformation, it's decreasing. We gave the initial velocity as 8.94 m/s, but in the graph, the initial velocity is 9.3506 m/s, it’s increased a little bit, Because due to inertia.

Interface [TYPE 7]:

The graph was obtained for the Type 7 - Total Resultant Force Interface.

Sectional Force at Cross Member 1:

The graph obtained for the Sectional Force at Cross Member 1.

The maximum sectional force on Cross Member 1 is 2.26859 KN.

Sectional Force at Cross Member 2:

The graph obtained for the Sectional Force at Cross Member 2.

The maximum sectional force on the Cross Member 2 is 4.10581 KN.

Here the sectional force is more than the Cross Member 1. 

Sectional Force at Cross Member 3:

The graph obtained for the Sectional Force at Cross Member 3.

The maximum sectional force on the Cross Member 3 is 0.242456 KN.

Here for this Cross Member, the sectional force is very low when compared to the previous two Cross Members.

Variation in Sectional Forces:

 

All Energies:

All the energies have been plotted.

Kinetic energy:

The graph was obtained for kinetic energy.

Kinetic Energy is at its peak in the starting, why because we have a huge mass.

Kinetic energy is lower and decreases, why because, there is a velocity applied to the car component, so it’s getting deformed and the kinetic energy decreases.

The kinetic energy will decrease due to the decrease in velocity after the collision When the car hits the rigid pole. So, the kinetic energy decreases with respect to time.

Internal Energy:

The graph was obtained for internal energy.

The formula for Internal Energy is I.E = Q W.

Here the heat is neglected because there is no heat transfer, We will be having only work done.

W=FxD

F=ma

Here the internal energy is in Zero because there is no deformation initially, So the internal energy is in Zero and starts from Zero and goes on increasing.

The internal energy increases because the deformation is happening, there is a displacement, So the internal energy increases, when the displacement or deformation occurs.

Contact Energy:

The graph obtained for Contact Energy.

Here the contact energy starts from the origin, Cause the Car is in its initial condition.

Initially, there is no contact between the Car and Rigid Pole.

There is also no deformation initially, but when the car goes and hits on the rigid pole, The contact energy starts increasing.

When the deformation or displacement happens to the car, the contact energy increases, causing the car component comes into contact with the rigid pole. So, the contact energy goes on increasing.

Hourglass Energy:

The graph obtained for Hourglass Energy.

Total Energy:

The graph obtained for Total Energy.

Total Energy is the sum of Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.

Here total energy starts from a higher value, in starting itself it's increasing, why because the total energy is the sum of Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.

All energies are in initial condition except kinetic energy, so kinetic energy is only their Total Energy=Kinetic Energy+0+0+0.

Kinetic energy is directly proportional to the total energy.

So, the total energy is increasing in the beginning.

Due to a -0.3% of energy error, the total energy is decreasing.

Result:

Hence the COG from the initial position has been changed to the required position by mass balancing.

Hence the penetrations and intersections have been verified successfully.

Hence the interfaces were created newly.

Hence the peak velocity has been given to the inner node of the doo.

Hence the initial velocity was assigned.

Hence the springs were created to obtain the intrusions.

Hence the rigid pole was created successfully.

Hence the TH for all inputs was created in order to obtain outputs.

Hence the simulation was run successfully without any errors.

At last, all the graphs were plotted with the obtained results.

Conclusion and Learning Outcome:

In this Challenge, I came to know about

How to change the COG position.

How to check for the penetrations and intersections.

How to create the interfaces and how to find connectivity, to check whether the free parts exist in the component.

How to give Peak Velocity of an inner node of the door.

How to assign the initial velocity.

How to create the springs to obtain intrusions.

How to create a rigid pole according to FMVSS 214 Standards.

How to request outputs.

Learned about the FMVSS [Federal Motor Vehicle Safety Standards].

Learned about the sectional forces, and axial forces.

 

https://drive.google.com/drive/folders/1wl1N2p6XmIAPPhk-e62Ui79H8iY442SN?usp=sharing