Assignment 7-Side Pole Crash Simulation Challenge

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 cylindrical rigid wall with a friction 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.

 

Output Deliverables :

• Sectional force in the cross member.
• Intrusion at B pillar,hinge pillar and fuel tank region. Provide recommendations on what can help to reduce Fuel tank intrusion.
• Peak velocity of an inner node of the door.

 

Software used : Explicit solver - Radioss 2022.

 

Theoretical framework:

• A side pole crash test is a type of automotive safety test designed to evaluate a vehicle's protection for occupants in the event of a collision with a pole or a tree on the side of the vehicle. In this test, a vehicle is propelled sideways into a rigid pole or barrier, simulating a common real-world accident scenario.
• The objective of the side pole crash test is to assess the structural integrity of the vehicle's side and its ability to manage the energy generated during a side impact. The test evaluates various factors, including the effectiveness of side airbags, door reinforcement structures, and the overall design of the vehicle's side frame.
• Crash test dummies equipped with sensors are typically used to measure the forces and accelerations experienced by occupants during the crash. This data helps assess the likelihood of injury to occupants and allows manufacturers to improve vehicle designs to enhance occupant safety.
• Overall, side pole crash tests are an essential component of vehicle safety evaluations, helping consumers make informed decisions and encouraging manufacturers to continually improve the safety of their vehicles.

        

 

     Federal Motor Vehicle Safety Standard (FMVSS) No. 214

• FMVSS No. 214, established by the National Highway Traffic Safety Administration (NHTSA) in the United States, is a federal regulation that specifies requirements for side impact protection in vehicles. This standard is aimed at reducing the risk of injury to occupants in side impact collisions, including those involving poles or trees.

 

      Euro NCAP side pole crash test

• Its a rigorous evaluation designed to assess a car’s ability to protect occupants during a side impact collision with a rigid pole or tree. Let me provide you with more details
• In this test, a car is propelled sideways at a speed of 32 km/h (approximately 20 mph) directly into a narrow, rigid pole. The car is positioned at right angles to the direction of motion or, as has been done since 2015, at a slight angle away from the perpendicular.

 

Procedural steps :

Step 1 : Check unit system

Step 1A : Import the solver deck model

•  File > Import > solver deck > browsed to select neon_side_reduced_0000.rad file > imported it.

         

 

Step 1B : Check the unit system.

• Model Browser > Control Cards > BEGIN_CARD > checked unit system is Kg-mm-ms

        

 

Step 2 : Import the model in Hypercrash application.

• Menu Bar > Applications > HyperCrash > Shown in below unit system
• In hypercrash > File > import > radioss > neon_side_reduced_0000.rad file.

         

 

 

 

Step 3 : Mass balancing of the model

 

• Check the Mass and COG by HyperCrash Menu Bar > Mass > Balancing. So,total mass of the model is 188 Kg

         

         

 

Step 4 : Add mass of the model

• Mass should be added to get COG in a proper position.It should be in centre of the cross member.
• To bring COG to the centre of the cross member,We should add a mass.
• To add mass by Menubar > Load Case > Added Mass.
• Right click on added mass tree > create new > Type:1 > In Support > graphics display by pick mode option n- by pick one node on the FE model.
• Then add remaining mass 700-165.433 =534.567 Kg in added mass option .
• Now mass should be added to get COG in a proper driver seat position

        

       

 

     Now checked the added mass in total mass of the model.

     

 

 

Step 5 : Export the hypercrash file into radioss file

• Menubar > file > export > Radioss format > saved it .

 

Step 6 : Import the radioss file in the Radioss deck solver and check the mass and COG details.

 

• Menubar > file > import > Radioss format > imported it 

        

 

Step 7 : Penetration check

 

• Menu Bar > Tools > Penetration Check- 0 collisions found .

       

 

Step 8 : Creation of contact interfaces

Step 8A : Creation of Self contact interfaces of all components.

• RMC on the model tree to create contact .
• The slave and master node settings, all the components in the model are selected. Therefore, this interface card will cover all the components in the model.

         

        

 

 

 Step 9 : Creation of Section at Cross Member 

 Step 9A : Creation of Frames

• Here we have to create a section,the section should be created at the cross member.
• Next for creating section,We need frame,So we need to create frame first.To create frame Right click on the Solver Browser > Create > Frame > Mov. 

        

 

          

           

Step 9B : Creation of sections

 

• Right Click on the Solver Browser > SECT > SECT.
• After selecting the SECT to create section,A parameter window will be opened left side.
• There will be Nodes (N1,N2,N3),Select the nodes to create a section.
• Next select the frame id by picking coordinate in the model.
• Enter the values for deltaT and alpha.
• Coefficient of filtering (alpha=0.67).
• Time step for saving the data (deltaT=0.001).
• Then RMC on the grshel_id to create/ edit to create set by selecting the elements along crosssection.

        

        

   Step 10:Creation of Intrusion at B-Pillar,Hinge Pillar and Fuel Tank Region :

   Step 10A : Creation of temp nodes

• Here we have to create intrusions at B-Pillar,Hinge Pillar and Fuel Tank Region.
• First we have to create spring 1D element,To create,First create a temp node on the B-Pillar base component.

        

       

 

   Step 10B : Creation of spring elements

• 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.

          

 

 Step 10B : Creation and assign of spring property.

• Create a property and assign the property to the Spring Collector 

         

     

        

 

Step 11 : Create Initial Velocity 

• To give the initial velocity to the car by the following methods.
• So to give the initial velocity we have to create INIVEL.
• To Create,Go to Solver Browser > Right Click > Create > Boundary Conditions > INIVEL.
• Car body to move in the x-direction so we have to give the velocity in the x-direction only.
• The test vehicle must impact the fixed, rigid pole laterally at a speed up to and including 32 km/h (20 mph)
• We need to give the velocity as 20 mph = 8.94 mm/msec.

         

     

 

Step 12 : Mark the peak Velocity of inner Node of the Door 

• To create a peak velocity,First we have to create a node.
• We have to give peak velocity at the node 337773.
• To find the node,Go to Display Panel.
• To find we have to display the numbers in the display panel.

         

 

Step 13: Create rigid wall with friction 0.1 

• To create cylindrical rigid wall,Cause this side pole crash,So.
• To create Rigid Wall,Right Click on Solver Browser > Create > RWALL > CYL.

        

• Next to create a temp node on the car door to make a cylindrical rigid wall.
• After creating a temp node,Translate that node to the 300 mm.
• After translating a node,In the RWALL parameter window,We have to select (XM,YM,ZM).It is selcted by,Clicking on the node which was translated.
• And the few parameters such as Friction, diameter of the cylindrical pole (Rigid), Searching tolerance(Dsearch)

        

 

       

 

• Now for XM,Select the Node Translated
• Normal,In the Z axis,Give the value as 1 .
• Give the values for all the parameters as shown in below,
• The Federal Motor Vehicle Safety Standard (FMVSS) No. 214 specifies a diameter of 254 millimeters (10 inches) for the rigid pole 

 

        

       

 

Step 14 : Request TH File for the Required Outputs and Give Time Step Value

 

• 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.

        

 

     

 

  

 

Step 15 : TH for Interface

• To request TH for Interface,Right Click on the Solver Browser > Create > TH > INTER.
• In entity IDs select the  interface contact already created in model browser as a groups.

        

 

 

Step 17 :TH for the Sections

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

       

 

 

Step 18 :TH for the intrusion

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

 

Step 19 : Setup the simulaion time

• In the model browser, Cards > ENG_RUN to change the simulation time.
• In the entity editor, T_stop is given the value of 80ms.

        

 

Step 20 : Model checker :

• To check the solver deck model by the following steps .
• Menubar > tools > model checker > Radioss block.
• If error is found need to be fixed.

 

         

        

 

 

Step 20 : Run the Simulation

• Now run the simulation,To run simulation,Go to Analysis Panel as shown in below Figure 100.
• Go to Analysis Panel > Radioss > Select the Input File > Save it in Different Folder and Rename it as Test-7 > 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 faste.

        

Step 20A: Debugging the errors.

• Errors of using unused sets , deleted the unused sets and fixed it.
• Errors of using empty comp , deleted the  empty components and fixed it.
• Errors of unidentified field in rntity in TH , so provide the no of variables in TH to fixed it.
• Errors of spring element definition is none so provide the none to part definition to fixed thiss error.

STEP 21 : Check engine 0001.rad file.

• After the end of the solver output go and check whether the engine has been edited or not.
• To check go to the file location where you have saved the starter file.
• Open the Test_3_neon_side_reduced_0001.rad file.

         

 

Step 22: Check the output file.

• Now go and open the 00001.out file with notepad.
• The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error.

     

•     The acceptable energy error is -15% to +5%.
•     The acceptable mass error range is 0 to 2 % .

 

STEP 23 : Post processing

1) Review the Simulation using -HyperView.

2) Plot the graphs using -Hypergraph 2D.

3) Review the Simulation using -HyperView.

• First to begin the postprocessing in the Hypermesh,Split the Screen .
• Import the animation file .h3d into the 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 .
• Now switch to the Von Misses Stress in result type and select the component,select the averaging method as simple and then click apply.

 1.)Stress contour :

     Max stress developed = 0.311 Gpa    

    

 

 2.) Displacement contour :

        Max displacement =  771 mm

         

 

3.) 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 Measure tool IN from HyperView and select the end node of the springs to know the distance between them

 3a1) Intrusion at fuel tank Region 

         

 

• Defining the nodes at the end of the spring at the initial position before the collision,The magnitude for the spring is 1400.558 mm.  

        

 

• Defining the nodes at the end of the spring after the collision,The magnitude for the spring is 1285.834 mm.

         

• Intrusion [Spring] at fuel tank Region is 1400.558 - 1285.834 = 114.72 mm.

3a2) Resultant elongation of spring element between fuel tank region

 

         

•   Resultant elongation of spring element between fuel tank region = 136.17 mm

 

 

 

 

3b1) Intrusion at hinge pillar Region. 

•   Defining the nodes at the end of the spring at the initial position before the collision,The magnitude for the spring is 1358.86  mm. 

        

 

• Defining the nodes at the end of the spring after the collision,the magnitude for the spring is 1331.75 mm.      

        

• Intrusion [Spring] at hinge pillar Region is 1358.86- 1331.75 = 27.11 mm.

 

3b2) Resultant elongation of spring element between hinge pillar region 

        

       

• Resultant elongation of spring element between hinge pillar region = 26.52 mm

 

3c1) Intrusion at B-pillar base  Region

•  Defining the nodes at the end of the spring at the initial position before the collision,The magnitude for the spring is 1321.97 mm.   

         

 

• Defining the nodes at the end of the spring after the collision,The magnitude for the spring is  1033.24 mm.      

        

• Intrusion [Spring] at Bpillar pillar base Region is 1321.97 - 1033.24  = 288.73 mm.

 

3c2) Resultant elongation of spring element between B-pillar base region

• Resultant elongation of spring element between fuel tank region = 286 mm.

 

4.) Peak Velocity node at inner door.

       

     

•  The peak velocity of the node on the door is 9.51mm/msec.The graph is in Zig-Zag form,Due to the noise and vibration,When the the car hits the pole.
• Here the the velocity is starting from peak due to the initial velocity is given and it goes on decreasing,cause the car goes and hits the pole,due to deformation,itse decreasing.
• Initial velocity as 8.94 m/s,But in the graph,the initial velocity is 9.51 m/s,It's increased little bit,Because due to inertia.

 

5.) Interface [TYPE 7] 

• The graph obtained for the Type 7 - Total Resultant Force Interface.
• Here the interfaces curve starts from origin and reaches peak due to collision.
• And it increases & decreases before it reaches to peak value,Cause there will be a contact forces acting with in the car before collision.

 

         

        

           Maximum resultant force = 39.24 KN.

 

6.)  Sectional Force at Cross Members

6a.) Sectional Force at Cross Member 1

• The graph obtained for the Sectional Force at Cross Member 1 
• The maximum sectional force on the Cross Member 1 is 2.65 KN.
• Here the sectional force is more than the Cross Member 1.

       

       

6b.) 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 1.45 KN.
• Here the sectional force is more than the Cross Member 2.

       

 

6c.) 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  0.09 KN.
• Here the sectional force is more than the Cross Member 3.

        

 

 

7.) Plots of energies :

a.) Internal energy :

• The formula for Internal Energy is I.E = QW.
• 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.
• Max internal energy at the end of the collision = 5486.48  kg mm²/ msec²

                       

         

b.) Kinetic energy : 

• Kinetic Energy is at peak in the starting,Why because,we have huge mass.
• Kinetic energy is lower and decreases,why because,there is a velocity applied to the car component,so its getting deformed and the kinetic energy decreases.
• The kinetic energy will decrease due to the decrease in velocity after the collison,When the car hits the rigid pole. So,the kinetic energy decreases with respect to time.    Max Kinetic energy started =  27908 kg mm²/ msec²
• Min Kinetic energy at the end of the crash = 22131 kg mm²/ msec²

     

 

C.) Contact energy :

• Here the contact energy starts from origin,Cause the Car is in intial condition.
• Intially there is no contact between the Car and Rigid Pole.
• There is also no deformation intially,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,cause the car component comes within the contact to the rigid pole.So the contact energy goes on increasing.
• Max contact energy at the end of the crash = 164.75 kg mm²/ msec².

          

 

d.) Hourglass energy :

• Hourglass Energy should be less than 10% of Internal Energy .   
• Here Hourglass energy is 26.51 .
• 10% of Internal Energy is 548.6 > Hourglass energy is  26.51 .

 

 

 

e.) Total energy :

• Total Energy is sum of Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.
• Here total energy starts from higher value,In starting itself its increasing,Why because the total energy is sum of  Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.
• All energies are in initial condition except kinetic energy,So kinetic energy is only there
• Total Energy=Kinetic Energy+0+0+0.
• Kinetic enrgy is directly proprtional to the total energy.
• So the total energy is increasing in the beginning.
• Due to -0.1% of energy error,the total energy is decreasing.
• Max total energy started =  27908 kg mm²/ msec² is always equal to the kinetic energy started.
• Due to -0.1 % of energy error,the total energy is decreasing at total energy at the staring of the simulation with error is 27880 kg mm²/ msec².
• Max contact energy at the end of the collision = 27617 kg mm²/ msec².

        

 

Result :

• Hence the COG from the initial position has been changed to the required position by mass balancing.
• Hence the penetrations and intersections has been verified successfully.
• Hence the interfaces 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 were created inorder 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 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 exsist in the component.
• How to give Peak Velocity of 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 Saftey Standards] 214.
• Learned about the sectional forces,axial forces.