Roof Crash Simulation on Car BIW

Roof Crash Simulation 

 

Aim -

• To run the roof crash simulation on the neon car model and plot the graphs for the neon car model in post processing.

 

Objective -

• To translate the impactor to the desired location as per the question.
• To create a Type 7 contact interface between impactor and car.
• To create a boundary condition for the suspension shock tower and lock them in Z direction.
• To create a moving SKEW to define the direction normal to the impactor.
• To create a impactor boundary condition.
• To apply a imposed displacement for the impactor.
• To create control cards.
• To set the termination time, nodal & element-time step.
• To request the output and run the simulation.
• To plot the graphs in the post processing.

 

Theoretical FrameWork :

• FMVSS 216, Roof Crush Resistance, establishes strength requirements for the passenger compartment roof of passenger cars, multipurpose passenger vehicles, trucks, and buses with a GVWR of 2722 kilograms or less.
• The purpose of the standard is to reduce deaths and injuries due to the crushing of the roof into the passenger compartment in rollover accidents.
• The prescribed static loading device is a rigid unyielding rectangular block 762 millimeters by 1,829 millimeters. It shall not move more than 127 millimeters to achieve the specified resistive load when applied to the forward edge of a vehicle’s roof.
• The resistive load to be achieved is 1½ times the unloaded vehicle weight (UVW) of the test vehicle or 22,240 Newtons, whichever is less. Both the left and right front portions of the vehicle's roof structure shall be capable of meeting the requirements. 
• The passenger car's sills shall be placed on a rigid horizontal surface and fixed rigidly in position. The vehicle's windows shall be closed and the doors shall be locked.
• This standard does not apply to school buses and passenger cars that conform to the dynamic rollover test requirements of FMVSS 208, Occupant Crash Protection, S5.3 by means that require no action by passenger car occupants.
• It also does not apply to convertibles, except for optional compliance with the standard as an alternative to the rollover test requirements in S5.3 of FMVSS 208.

 

 

Figure 1-Roof Crash.

 

Figure 2-Roof Crash Animation.

 

Procedure -

 

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

• While opening hyper mesh software, A user profile window will pop up, Switch to the radioss user profile as shown in below Figure 3 and start importing the model into the solver deck.

 

Figure 3-User Profile Window.

 

• Now after switch the user profile to radioss,import the model (starter file) into the radioss solver deck.
• To import the model,Go to Standard Panel >> Import >> Import Solver Deck.

 

Figure 4-Importing Model into Radioss Block.

• Import Solver Deck option should be selected to import the radioss starter file.
• First, import the Car BIW model into the GUI.Which is shown in below Figure 6.

 

Figure 5-Selecting the Starter File to Import.

 

• Here the import browser will appear as shown in above Figure 5,Select the appropriate starter file to import into GUI.
• Switch the File Type to Radioss Block and import the model into GUI.
• Next import the impactor into the GUI which is shown in below Figure 7.

 

Figure 6-Car BIW Model Imported into GUI.

• Next import the impactor into the GUI which is shown in below Figure 7.

 

Figure 7-Impactor Imported into the GUI.

 

• Here the model is in wireframe mode,Switch to the shaded mode as shown in below Figure 8.
• To switch to shaded mode,Go to Visualization Tab >> Shaded Elements and Mesh Lines.

 

Figure 8-Visualization Tab to Switch to the Shaded Elements and Mesh Lines.

 

Figure 9-Shaded Elements and Mesh Lines Mode.

• 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 is shown in below Figure 10.

 

Figure 10-Unit System [kg,mm,ms.]

 

 Phase 2-Check for the Penetration :

• Here check for the penetrations,To check,Go to Menu Bar >> Tools >> Penetration Check.Which is shown in below Figure 11.

 

Figure 11-Tools Menu.

 

• Next select the groups [Interfaces] to define.Which is shown in below Figure 12.
• Then click on the check to check penetrations in the model,If the penetration exsist,It throw a error in the status bar,If the penetration dosen't exsist,it will display No Collisions Found which is shown in below Figure 12.

 

 

Figure 12-Status Bar.

 

Phase 3-Create the Interfaces :

 

1) Car and Impactor -

• Here for this model,TYPE 7 Contact Interface is created with the recommended parameters.To create interface,Right Click on Solver Browser >> Create >> Inter >> TYPE 7.Which is shown in below Figure 13.
• First we have to create Contact Interface for the Car and Impactor which is shown in below Figure 14.

 

 

Figure 13-Creation of Interface.

 

Figure 14-Type 7 Contact Interface for Car and Impactor.

• Select the slave and master nodes by switching to the components and select all the car components for slave which is shown in below Figure 15 and for master nodes select all the components of Impactor which is shown in below Figure 16. 

 

 

Figure 15-Car Components Selected for the Slave Nodes.

 

Figure 16-Impactor Components Selected for the Master Nodes.

 

2) Self Impact -

• The Type 7 Contact Interface for the Self Impact is created which is shown in below Figure 17.

 

Figure 17-Type 7 Contact Interface for Self Impact.

• Here for the self impact,Select the slave and master nodes by switching to the components and select all the car components for slave and master which is shown in below Figure 18 and 19. 

 

 

Figure 18-All the Car Components Selected for the Slave Nodes for Self Impact Interface.

 

Figure 19-All the Car Components Selected for the Master Nodes for Self Impact Interface.

 

Phase 4-Create Boundary Conditions for the Suspension Shock Tower :

 

• Here we have to create boundary conditions for the suspension shock tower.
• To create boundary conditions,Right Click on Solver Browser >> Create >> Boundary Conditions >> BCS,Which is shown in below Figure 20.

 

Figure 20-Creation of BCS.

• Now we have to fix the Z-Direction [Constraint] for the suspension tower.Which is shown in below Figure 25.
• To fix the Z-Direction of suspension tower,We need to deploy a cluster rigid connections on the suspension tower which is shown in below Figure 23.
• To deploy a cluster rigid connections,Go to 1D Panel >> Rigids >> Create >> In Nodes 2-n option, Switch to Multiple Nodes >> In Primary Nodes Option,Switch to the Calculate Node >> Create.

 

Figure 21-1D Panel.

 

 

Figure 22-Rigids Tool Sub-Panel.

• After deploying the rigid connections to the suspension shock tower,Which is shown in below Figure 23.
• Constrain the Z-Direction of the suspension shock tower which is shown in below Figure 25.

 

Figure 23-Rigid Connections Deployed to the Suspension Shock Tower.

• Select the nodes of the rigid connections,Where we deployed.Which is shown in below Figure 24.

 

Figure 24-Selecting th Nodes of Suspension Shock Tower.

 

Figure 25-Constrained the Rotational and Translation Z-Axis For Suspension Shock Tower.

 

Phase 5-Create a BCS [Boundary Conditions] to Fix the Free End of the Spring :

 

• Here we have to create the boundary condition to fix the free end of the spring.And rename it as spring.
• To create boundary conditions,Right Click on Solver Browser >> Create >> Boundary Conditions >> BCS,Which is shown in below Figure 26. 

 

Figure 26-Creation of BCS.

• After creating the BCS rename it as spring which is shown in below Figure 27.
• Now select the free end of the spring which is shwon in below Figure 27.

 

Figure 27-Selecting the Free End of the Spring.

 

• Now Constrain all the degree of freedom for the free end of the spring which is shown in below Figure 28.

 

Figure 28-Constrained all Degree of Freedoms for the Free End of the Spring.

 

Figure 29-Selected the Free End of Spring and Fixed all the Degrees of Freedom.

 

Phase 6- Create a Moving SKEW to Define the Direction Normal to the Impactor’s Face :

• Next we have to create the boundary condition for the master node of the impactor.
• For that first,We want the impactor to move only in perpendicular direction to the impactor.
• To give the boundary condition to the master node.We need to create a skew.
• To create a skew,Right Click on Solver Browser >> Create >> SKEW >> Mov.Which is shown in below Figure 30.

 

Figure 30-Creation of SKEW.

• To create the skew,Select the option create by node reference and define the Z-axis and YZ-plane.Which is shown in below Figure 32.

 

Figure 31-Skew Panel.

 

Figure 32-Nodes Selected.

Figure 33-Origin,Axis,Plane Node Selected.

• The skew created which is shown in below Figure 34.

 

Figure 34-SKEW Created.

 

Phase 7- Create a BCS to Guide the Master Node of the Impactor Rigid Body :

• Now we have to give the boundary condition to the master node of the impactor. 
• To give,we have to create boundary condition and rename it as Impactor_Rigid_Master_Node.
• To create BCS,Right Click on Solver Browser >> Create >> Boundary Conditions >> BCS,Which is shown in below Figure 35.

 

Figure 35-Creation of BCS.

• After creating the boundary condition,Select the master node of the impactor which is shown in below Figure 36.

 

 

Figure 36-Master Node Selected.

 

• Now constraint all the DOF [Degrees of Freedom] apart from the Z-Axis.Which is shown in below Figure 37.

Figure 37-Constraint all DOF Except Z-Axis.

• Next select the skew in the skew ID.Which is shown in below Figure 38.

 

Figure 38-Skew ID Selected.

 

Phase 8-Give the Imposed Displacement to the Impactor :

• Here we have to give the imposed displacement to the impactor.
• To give the imposed displacement to the impactor. We have to create the boundary condition. 
• To create the boundary condition, Right-click on the Solver Browser >> Boundary Condition >> IMDISP.Which is shown in below Figure 39.

 

Figure 39-Creation of Imposed Displacement.

• After creating the imposed displacement,we have to select the impactor master node.
• To select the impactor node,Below the Parameter Window >> Right Click on gmd_ID >> Create Edit >> Enitiy ID >> Select the Node >> Proceed,Which is shown in below Figure 40.

 

 

Figure 40-Selected the Impactor Master Node.

 

• Next we have to create the curve to assign.
• So we want to impose the velocity of the impactor starting from 0 mm/s at t = 0 and the displacement of the impactor should be 200 mm at 200 ms.
• So we have to create a curve.To create the curve ,Go to the Model Browser >> Create >> Curve.Which is shown in below Figure 41.

 

 

Figure 41-Creation of Curve for Imposed Displacement.

• The curve created is shown in below Figure 42.

 

 

Figure 42-Curve Created.

• Now assign this curve to the imposed displacement,To aasign,Go to the fct_ID(T) >> Click on Curve >> A Window Will Pop Up >> Select the Curve >> Ok.Which is shown in below Figure 43.

 

 

Figure 43-Curve Assigned to the Imposed Displacement Card.

• Now Select the skew to move the impactor according to the skew.
• Switch to the Z-Axis Direction to move the impactor in Z-Axis Direction which is shown in below Figure 44.

 

 

Figure 44-Defined SKEW to the Imposed Displacement Card.

 

Figure 45-Selected and Reviewed the Impactor Master Node.

 

Phase 9-Create Missing Control Cards :

• Here there are only cards present in the model which is shown in below Figure 46 ,Soo we have to create other missing cards.

 

Figure 46-Control Cards.

• After creating the control cards,The Necessary control cards is shown in below Figure 47.

 

Figure 47-Necessary Control Cards.

• To create control cards,Go to Analysis Panel >> Control Cards.Which is shown in below Figure 48.

Figure 48-Analysis Panel.

 

Figure 49-Control Cards Panel.

• The time history file should be printed at 0.0001s.Create ENG_TFILE card.Which is shown in below Figure 50.

Figure 50-ENG_TFILE Card.

• The simulation should be run for 200 ms. So create ENG_RUN card.Which is shown in below Figure 51.

Figure 51-ENG_RUN Card.

 

• The animation file should be created for every 0.005s. So create ENG_ANIM_DT card.Which is shown in below Figure 52.

Figure 52-ENG_ANIM_DT Control Card.

 

• 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 which is shown in below Figure 53.

 

Figure 53-Values Entered in ENG_DT_BRICK,ENG_DT_INTER,ENG_DT_NODA Control Cards.

• Next we have to include elemental energy, equivalent plastic strain, hourglass energy, von mises stress. So to include all these energies we have to create the  ENG_ANIM_ELEM control card and check all these energies in the control card,Which is shown in below Figure 54.

 

Figure 54-ENG_ANIM_ELEM Control Card.

 

• We have to request the TH to get the required output.
• First request the TH for the Contact Interfaces,To create TH,Right Click on the Solver Browser >> TH >> INTER.Which is shown in below Figure 55.

 

Figure 55-Requesting TH for Interface.

 

• 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.Which is shown in below Figure 56.

 

Figure 56-TH for Interface Created.

• TH created for all the required files which is shown in Figure 57.

Figure 57-TH Created for all the Required Files.

 

Phase 10-Checks :

• Finally,After doing all the load case setup,We have to check for the errors,Whether every load case setup is fine or not.
• To check,Go to Tools >> Model Checker >> Radioss Block.Which is shown in below Figure 58.

 

Figure 58-Tools Bar.

• Next the model checker window will be open which is shown in below Figure 59.
• There right click on the browser and click run or hit on green check mark in the window,which will run and identify if the error exsist in the model load case setup.

 

Figure 59-Model Checker Window.

 

Figure 60-Error in Load Case Set-Up.

• To fix the error shown in above  Figure 60.
• Isolate that error which is shown in below Figure 61,and see where the error has occured.The error occured is shown in below Figure 62.

 

Figure 61-Error Isolated.

• To fix the error which is shown in below Figure 61.To fix this delete the 1D rigid element to fix this error which is shown in below Figure 62.

 

Figure 62-Delete the 1D Rigid Element.

 

Figure 63-Error Solved.

 

Check for Connectivity :

• To check for the connectivity,Go to Tools >> Find Connectivity >> Window Pop-Up >> Below Parameter Window >> Select all Components >> Check.Which is shown in below Figure 64.

 

Figure 64-Check for Connectivity.

 

• When you check connectivity for the model,A window will Pop Up,There in the Select Entities option,Select all the components which is shown in below Figure 65.

 

Figure 65-Select all the Components.

• After checking connectivity for the model,The software will throw the free parts which are not connected which is shown in below Figure 66.

Figure 66-Free Parts.

 

• Here there are many free parts,The free parts should not exsist,If they exsist in the model,It will effect the simulation,Means,If you run the simulation with free parts,while reviewing the simulation,the parts will be flying which is shown in below Figure 67.

 

Figure 67-Free Parts.

• To connect the free parts,Go to 1D Panel >> Rigids >> Create >> In Nodes 2-n option, Switch to Multiple Nodes >> In Primary Nodes Option,Switch to the Calculate Node >> Create.Which is shown in below Figure 68 and 69.

 

Figure 68-1D Panel.

 

Figure 69-Rigids Tool Sub-Panel

• Connected the free part with rigid connections which is shown in below Figure 70.
• Similarly connect all the free parts with the rigid connections.

[Note : Don't connect free parts with cluster rbe2 elements,it will effect your energy error.Which is shown in below Figure 71.]

 

 

Figure 70-Connected Free Part With Rigid Connections.

 

Figure 71-Don't Connect With Cluster RBE2 Elements.

• After checking connectivity and errors in the hypermesh,Go and check in HyperCrash also,Cause hypermesh doesn't give you exact results,So its better to go and check in hypercrash after doing load case setup in hypermesh.
• Open hypercrash and import the radioss file into the GUI.
• Go to Browser >> Tree >> Select the Model Tree.Which is shown in below Figure 72.

 

Figure 72-Selected the Model Tree.

• After selecting the model tree,Go to the Menu Bar >> Quality >> Check Connectivity of Tree Selection.Which is shown in below Figure 73.

 

Figure 73-Select Check Connectivity of Tree Selection.

• There are no free parts in the model after checking connectivity in the hypercrash which is shown in below Figure 74.

 

Figure 74-No Free Parts Exsist.

• Now check for the errors in the hypercrash cause in hypermesh,it will not show you a exact error,So check for the errors also in hypercrash,which is shown in below Figure 75.

 

Figure 75-Checking for Errors in the HyperCrash.

• There are no errors which is shown in below Figure 76.

 

Figure 76-No Errors.

 

Figure 77-Checking Connectivity in HyperMesh and HyperCrash.

[Note :After checking connectivity and errors in the hypermesh,Go and check in HyperCrash also,Cause hypermesh doesn't give you exact results,So its better to go and check in hypercrash after doing load case setup in hypermesh.]

 

 Phase 11-Run the Simulation :

• Now run the simulation,To run simulation,Go to Analysis Panel as shown in below Figure 77.
• 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 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.

 

Figure 77-Analysis Panel.

 

Figure 78-Radioss Sub-Panel.

 

• After completing the simulation,the radioss will pop up a solver window stating Radioss Job Completed which indicates the simulation has been completed.
• Here the number of animation steps obtained  are shown in below Figure 79.

 

Figure 79-Animation Files Obtained.

• Now go and open the 00001.out file with notepad.First, we will check Energy error and Mass error. So we will open the engine .out file of the model and check the last row for Energy and Mass error as shown below.
• The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown in below Figure 80.

 

Figure 80-Obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error.

 

• The Red One indicates Energy Error which is -25.1% which is negligible.The acceptable range for energy error is -15% to 5%.
• The results above shows that the energy error exceeds the acceptable range.
• This is mainly due to the boundary conditions which we applied on rigid bodies.
• As the rigid bodies are already defined with boundary conditions,We are again giving boundary conditions.
• We applied external boundary conditions on the rigid bodies using BCS collector. Thus some amount of energy error is induced due to over defining boundary conditions.
• As the model is not a complete vehicle model, some parts of the car ruptures on increasing force from the impactor which also results in energy error. Due to all these factors, the energy error in the model exceeds the acceptance range. 

 

There are also other reasons ,It may also due to the :

`***`Position of the Impactor

`***`Increase of Hourglass Energy 

`***`Type of Analysis

 

• The time taken to complete the simulation and the elapsed time is shown in below Figure 81.

 

Figure 81-Time Taken to Copmlete the Simulation and Elapsed Time.

 

Phase 12-Post Processing :

1) Review the Simulation using -HyperView.

2) Plot the graphs using -Hypergraph 2D.

 

1) Review the Simulation using HyperView :

• 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 differnt ways to load the input deck and their corresponding results into hyperview.
• First to begin the postprocessing in the Hypermesh,Split the Screen as shown in below Figure 82.
•  Import the animation file .h3d into the hyperview.

 

Figure 82-Splitting the Screen.

 

Figure 83-Screen Splitted into Two.

• And then activate the Client HyperView

Figure 84-HyperView Panel.

 

• To access the load model panel
• Select Load Model Button from the HyperView Panel and open .h3d file as shown in below Figure 85.

Figure 85-Opening .h3d File.

 

 

Figure 86-.H3D Model Loaded.

• After loading the model into hyperview,It will be represented as shown in below Figure 87.

 

Figure 87-Model Imported into HyperView.

• After importing the .h3d file into the GUI,Enable the contour.
• The contour tool create contour plots of a model graphically visualize the analysis results.
• To enable contour,Go to Results ToolBar >> Contour .

 

Figure 88-Contour Panel.

 

• Now switch to the Von Misses Stress in result type and select the component,select the averaging method as simple and then click apply as shown in below Figure 89.

 

Figure 89-Selecting the Paremeters in Contour Panel.

 

• After applying ,Run the Simulation,The Simulation animation in terms of Elements,Von Misses Stress and Displacement is shown in below Figure 90,91,92,93 and 94.

 

Figure 90-In Terms of Elements Animation.

 

Figure 91-Displacement Simulation Animation.

 

• Here the contour plot displays the displacement of each node of the BIW model of a car in a GUI.
• Displacements are computed with respect to the global co-ordinate system.
• As the impactor hits the car roof,the deformation occurs to each nodes and the nodes gets displaced from their initial position.
• During the simulation,maximum displacement occured at node 222436 which is shown in above Figure 91.

 

Figure 92-Von Misses Stress Simulation Animation.

 

• Here the contour plot gives the stress induced at each node in the BIW model of the car.
• As the impactor hits the car roof,internal stress is developed in the model due to the material behaviour.
• During this simulation,The maximum stress developed at each node is 122498 which is shown in above Figure 92.

 

Figure 93-Plastic Strain Simulation Animation.

 

Figure 94-Node Mass Simulation Animation.

 

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 sophisicated 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.

 

Figure 95-Switching to Hypergraph 2D.

 

• Here switch to the Hypergraph 2D to plot the graphs.
• To switch,Go to Client Selector >> Choose the Hypergraph 2D as shown in above Figure 95.

• [Note : Before plotting the graphs,Make sure to split the screen into three or four and then plot the graphs.]

• The first graph is plotted for the Righ Rail at the created section.

• To plot the graph,Go to Hypergraph 2D >> Data File >>Roof_CrashT01 >> Apply.

 

Interface [TYPE 7] Car and Impactor:

 

Figure 96-Type 7 Contact Interface (Car and Impactor) Graph.

 

• The graph obtained for the Type 7 - Total Resultant Force Interface (Car and Impactor) is shown in above Figure 96.
• Here the interfaces curve starts from origin and reaches peak due to collision.
• And it goes on increasing due to the contact within the car,When roof comes and hits the car,it goes on increasing.

 

Interface [TYPE 7] Self Contact :

 

Figure 97-Type 7 Contact Interface (Self Impact) Graph.

• The graph obtained for the Type 7 - Total Resultant Force Interface (Self Impact) is shown in above Figure 97.
• Here the interfaces curve starts from origin and reaches peak due to collision.
• The maximum total resultant foece obtained is 19.0459 KN.

 

FMVSS 216 Impactor Spring :

• The graph obtained for the impactor spring is shown in below Figure 98.

 

Figure 98-FMVSS 216 Impactor Spring.

 

All Energies :

• All the energies have been plotted which is shown in below Figure 99.

 

Figure 99-All Energies Graph.

 

Kinetic energy: 

• The graph obtained for kinetic energy is shown in below Figure 100.

 

Figure 100-Kinetic Energy Graph.

• Here in the above graph,We can see that,In the starting the impactor will be moving,So it will be having some velocity.
• So due to some velocity, there will be a kinetic energy.When the impactor hits with the car model the energy will transfer to the model and the kinetic energy of the model gets increases.So the kinetic energy goes on increasing.

 

Internal Energy :

• The graph obtained for internal energy is shown in below Figure 101.

 

Figure 101-Internal Energy Graph.

• The formula for Internal Energy is I.E = Q`pm`W.
• Here the heat is neglected,Cause there is no heat transfer,We will be having only workdone.
• 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 is shown in below Figure 102.

 

 

Figure 102-Contact Energy Graph.

• Here the contact energy starts from origin,Cause the Car is in intial condition.
• Intially there is no contact between the Car and Impactor.
• There is also no deformation intially,But when the Impactor goes and hits on the Car Roof,The contact energy starts increasing.
• When the deformation or displacement happens to the car,the contact energy increases,cause the car component comes within the contact to the impactor.So the contact energy goes on increasing.

 

Hourglass Energy :

• The graph obtained for Hourglass Energy is shown in below Figure 103.

 

Figure 103-Houglass Energy .

 

[Note : Hourglass Energy should be less than 5% of Internal Energy.]

• Here the hourglass energy is less than 5% of internal energy,So it is fine.

 

Total Energy :

• The graph obtained for Total Energy is shown in below Figure 104.

 

Figure 104-Total Energy Graph.

• Total Energy is sum of Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.
• Here total energy starts from origin,and it goes on increasing,Why because the total energy is sum of  Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.
• Kinetic energy is directly proportional to the total energy.
• So the total energy goes on increasing.

 

Force vs Displacement :

• We have to plot the Force vs Displacement,To plot,First we have to plot the displacement graph.
• To plot displacement graph,Go to HyperView >> Build Plot.Which is shown in below Figure 105.

 

Figure 105-Build Plot Panel.

• Next in the drop down list box,Choose the Result type as Displacement,and then select the Magnitude.Which is shown in below Figure 106.

 

Figure 106-Select the Result Type as Displacement.

 

• Next select the Node,Where the displacement has to be calculated along the direction of motion and apply,To get the Displacement vs Time Graph. Which is shown in below Figure 108.
• The node should be selected on the car, which is shown in below Figure 107,Cause the displacement will occur for car not a impactor.

 

Figure 107-Node Selected for the Displacement.

 

Figure 108-Displacement vs Time Graph.

 

• Next we have to plot the total resultant graph which is shown in below Figure 109,How to plot the total resultant graph.
• We have to select the interface which we created for car and impactor.It is named as TYPE 7.Select that interface which is shown in below Figure 109.

 

Figure 109-Plotting the Total resultant Force Graph.

 

Figure 110-Total Resultant Force Graph Plotted.

 

• Next go to the Menu Bar >> Math >> Cross Plot.
• If math option is not available in the Menu Bar.
• To activate,Go to Menu Bar >> File >> Load >> Preference Files >> Vehicle Saftey Tools.Which is shown in below Figure 111 and 112.

 

Figure 111-Loading Math Option in Menu Bar.

 

Figure 112-Vehicle Saftey Tools.

• To cross plot Force and Displacement curve,Go to the Math Option in Menu Bar >> Two Curves >> Cross Plot,Which is shown in below Figure 113.

 

Figure 113-Math Panel.

• Next plot the cross plot for the Force and Displacement.Which is shown in below Figure 115.
• For the Curve X-Select the Displacement Curve by Shift + Left Click.Which is shown in below Figure 114.
• For the Curve Y-Select the Total Resultant Force by Shift + Left Click.Which is shown in below Figure 114.
• Use Current Plot while plotting the curve for Force and Displacement which is shown in below Figure 114.

 

Figure 114-Cross Plotting Force vs Displacement Curve.

• To rename X-Axis and Y-Axis to the Force and Displacement,Double Click on the X-Axis and Y-Axis,Then rename it as Force and Displacement which is shown in below Figure 115.

 

Figure 115-Renaming the X,Y-Axis to the Force and Displacement.

 

• The graph obtained for the Force vs Displacement is shown in below Figure 116.

 

Figure 116-Cross Plotted Force vs Displacement.

 

Check the FMVSS 216 target load of 47,000 N (= 3 * GVW) has been met :

 

Figure 117-Mass Details.

 

• To calculate the target load of the FMVSS 216,We should check the initial mass od the car, it is around 174.8487 kg.
• To convert it into the weight,We should consider the gravitational force. Therefore, the GVW value will be 1,715.2657 N.
• Load=3xGVW.
• Load=3x9.981x174.848.
• Load=3x1715.2657.
• Load=1,715.2657N.
• The target load given is 47000 N but the load attained here is 10% (1715.2657) of the target load. 
• This is due to,cause the car model given to us is not a complete car,Its a BIW body,So the target load we attained here is 1715.2567 N.
• For the whole car,The mass will be 1600 kg,If we check with this,We will be getting the target load as =3x9.91x1600=47088 N.
• If we run the simulation with complete car,We will be getting exact target load and it wil meet the target load.But here the target load is not met.

 

Final Image : 

 

Figure 118-Final Image.

 

Result :

• Hence the Impactor has been positioned according to the given axis.
• Hence the two interfaces created for the self impact,car and impactor.
• Hence the Boundary Condition created and locked the two nodes of Z-Axis for suspension tower.
• Hence the Boundary Condition created to fix the free end of the spring.
• Hence the SKEW created to define the direction normal to the impactor’s face.
• Hence the Boundary Condition created to guide the master node of the impactor rigid body.
• Hence the Imposed Displacement given to the Impactor.
• Hence all the neccessary control cards were created.
• Hence the TH for all inputs were created in order to obtain outputs.
• Hence the simulation was runned successfully without any errors.
• Atlast all the graphs were plotted with the obtained results. 

 

Conclusion and Learning Outcome :

`***`In this Challenge,I Learned about

• Learned about the roof crash test.
• Learned to create boundary conditions.
• Learned to translate the impactor according to the given axis.
• Learned to create imposed displacement.
• Learned to create the interfaces and how to find connectivity,To check whether the free parts exsist in the component.
• Learned to create cross plots.
• Learned  to request outputs.
• Learned about the FMVSS [Federal Motor Vehicle Saftey Standards] 216.