SIDE CRASH OF NEON DODGE BIW USING RADIOSS

AIM:

To analyze, the Neon side crash -BIW of the car and observe the resultant output and energy plots from the simulation.

OBJECTIVE:

1. To check the unit system and either follow[Mg mm s] or [Kg mm ms].
2. To create an appropriate interface, friction 0.2 and recommended parameters.
3. Make sure of no penetrations and intersections.
4. To create a rigid wall with friction 0.1 as per the reference model.
5. To compare the model weight with the full-scale 300k nodes model and use added masses to reach target weight 700kg while getting CG about the required range.
6. To give an initial velocity as per the standards.
7. Then use a model checker to ensure good quality.
8. Mention the time-step as 0.5 to 0.1 microseconds.
9. To run the simulation of frontal crash-BIW as 80 ms.

KEYWORDS: Rigid wall, Fuel tank, Intrusions, Velocity, Displacement, Rigid body, A-pillar, B-pillar, Cross-section.

SOFTWARE USED: Hypermesh and Hypercrash.

THEORY:

Pole impact test is not yet mandatory worldwide. USA defined an oblique pole impact test several years ago and it is now required via FMVSS n°214. In Europe, a pole test 90° is applicable in consumer testing but it is not mandatory. The main purpose of Euro NCAP when they introduced this test, in the early 2000s, was to incite the car manufacturers to fit head protection on the first row (curtain airbag is usually the protection device used to answer this request). Korea and Australia consumer organizations are also using the same test protocol. But here again, this is not a mandatory/regulatory requirement. And for the other countries in the world, no requirement exists so far for a pole test.

Regulatory and consumerism discussions currently take place on the definition of a pole impact that could be representative of car accidents in order to better protect the occupants. Two main test protocols are in competition: the FMVSS 214 one and the current Euro NCAP one. France, taking part in the discussion in WP29 GRSP, provided accident data as well as cost-benefit study. To supply data for this debate, PSA Peugeot Citroën carried out physical tests on different car platforms with the two types of impact:

• pole test 75° 32 km/h, also called “oblique pole test”
• pole test 90° 29 km/h

This study is based on the analysis of physical and numerical tests performed with the two test protocols on vehicles of different sizes and built on different platforms. We can split the study into three phases:

• The first phase was to make an initial picture of the consequences of the two tests on current cars in terms of intrusion and to derive correlated numerical models
• The second phase was to use numerical models to design the reinforcements needed to get the same intrusion level in the 75°-pole impact test as in the initial 90°-pole test.
• The third phase was to assess these reinforcements in physical tests to check if they were effective.

The aim of this study is to evaluate the cost/benefit ratio of regulation evolution for passenger cars and light commercial vehicles regarding side impacts. It was carried out to contribute to the WP29 discussion within the Pole Side Informal Working Group. For this discussion on a regulatory topic, two evolution types have to be considered they are the injury reduction in barrier side impact and the injury reduction in a pole side impact.

PROCEDURE:

Set-up has to be followed,

• First, we want to import the neon_side file by using the import option and select the file that we want to import the data of file name as neon_side_reduced_0000.rad that is referred to as an input file of the simulation and click import. Now the file is imported and the import selection process and import file dialog box is shown below,

Fig: Import Dialog box

• After importing, the input file a model will open and that is shown below,

Fig: Open model

• Now check the unit system and verify that the same pattern of the unit system has followed in this simulation. It could be in either [Mg mm s] or [Kg mm ms] that are mentioned by the instructor.
• The unit system is required to obtain the resultant plots in that certain units. The unit system for this simulation is shown below,

Fig: Starter file

• After verifying the unit system delete the default interface and to create an appropriate interface with the friction of 0.2 and using recommended parameters. Therefore create the interface of Type-7 by selecting the solver>inter>right click inter>select create and enter the recommended parameters in that properties card. Type-7 interface is using because it is nodes to surface contact. Select the master and slave in that interface group to obtain the results of energy between the master and slave components. Here the recommended parameters for the type-7 interface and the friction of 0.2 that we entered are shown below,

Fig: Selfcontact interface recommended properties

• Now check the penetration and intersection for the whole body of the vehicle by selecting tools>penetration check>select the group in the selection and click check to verify the group whether the penetration occurred or not.
• After checked the penetration it resultant that any occurred or not, hence this group is cleared from the penetration and intersection that is shown below,

Fig: Penetration Check

• Then create a rigid wall to crash the vehicle in a rigid plane(Crash Simulation) and observe the simulation and energy between the wall and vehicle. Right-click the solver>create>RWALL>select CYL>enter the properties of a pole of friction as 0.1 and the Dsearch as 1000. Select the engineering data and ensure the axis of XM, YM, ZM which denotes the vehicle movement from normal to a pole. Mention the pole diameter as 254mm that is referred from standards. In YM axis we are selecting any one node in the B-pillar to where the rigid pole wants to crash.
• And in normal N we initiate the distance between the rigid pole and the B-pillar.
• Therefore the RWALL properties and the data's given in this simulation are shown below,

Fig: Rigidpole Properties

A created rigid pole of friction as 0.1 and the side area is shown as below

Fig: Rigid with model

• Now we want to move the CG in the required range by adding the mass for each node and to create the excess mass for certain selected nodes that is depends upon the movement of CG.
• Ensure that CG should present between the center of the driver seat. First, we verify that the actual total mass present in nodes by selecting the mass>balancing option in hyper crash. Before that, import the edited file which is worked on hypermesh into the hypercrash.
• Here the actual total mass value shows as 166kg for 300k nodes. To view, the CG click the overview option and view the model it will show the CG as a dot point. That value is shown as below,

Fig: Default Mass

• To move the CG increase the mass value from 166kg to 700kg that value is mentioned by the instructor. By selecting loadcase>added mass> it shows the total nodes and the mass value for those nodes. Those values and separation of nodes are set as default. The selection of added mass is shown below,

Fig: Added mass

• In the added mass, click box icon it shows 8 different types that depend upon the distribution of mass with group or node. Here select Type=1(mass is distributed to each node of a node group) it will create a section, in that section enter the mass value to add total mass value in the frontal area of a vehicle.
• By balancing the mass value and creation of mass section will move the CG at the required point. The type selection of added mass is shown below,

Fig: Mass Type

• Therefore the mass is added through the mass type and 8 sections are created each section contain some amount of additional mass added in particulars node that is selected by the user. Now added mass section and the selected nodes are shown as below,

Fig: Selected node mass

• Now the total mass is reached as 700kg by adding the new mass value for some specified nodes and that value is initiate below,

Fig: Value-added mass

• By changing the mass of 700kg the CG has reached a required range that is in between the driver seat and B pillar. Mass balancing is used to change the mass value and to move the CG by adding the mass in different valid nodes. Hence CG is moved and that is shown as below,

Fig: Centre gravity point

• Now we want to give the initial velocity of a vehicle as 29mph that is given by the instructor. By right-click the solver>create>INIVEL> setup the properties by giving the value of velocity as 8.05mm/ms it is obtained by converting the unit of 29mph. Then click the gmd_ID and select the groups and confirm it.
• Therefore the initial velocity is created and that is shown as below,

Fig: Initial velocity

• After creating an initial velocity check whether the model is in good condition or not by using the model checker option. Select Tools>model checker>click run icon it will checks the total model and show the results. If any errors will appear after completion of the model checker clear the errors to run the simulation. Here the model checker is run completely and that is shown below,

Fig: Model checker in hypermesh

• It shows an error of Rbody Master on element while checking in the model checker that is shown by creating the rigid connection of the vehicle. Hence that is acceptable for this simulation so clear that error or change that error by warning and again run the model checker.

Fig: Error

• Now model checker run completely and errors also cleared that is shown as below,

Fig: Model checker

• Now check the penetration and intersection for the whole body of the vehicle by selecting tools>penetration check>select the group in the selection and click check to verify the group whether the penetration occurred or not.
• After checked the penetration it resultant that any occurred or not, hence this group is cleared from the penetration and intersection that is shown below,

Fig: Penetration Check

• Before running the model we want to check the connectivity of the whole part of the vehicle. By selecting the tools>find connectivity option check connectivity table will open select the entities of total components present in the car and select connector tickbox and click check option it will give the results of connectivity in the vehicle.
• If any free body is shown as an error in that check that will rectify by connecting that part with rigid or spring in 1D toolbar option.
• The connections will check and after getting find connectivity completely then proceed for another step. The connectivity is checked completely and that is shown as below,

Fig: Find connectivity Check

• To mention the time step as 0.5 to 0.1 microseconds by selecting the solver>engine keywords>dt/noda and enter the value of Tmin in that setup table as 0.0001. And to set the run time of simulation as 80ms by selecting solver>engine keywords>run>Tstop and enter the simulation run time. The time step and run time setup data are shown below,

Fig: Timestep and Run time properties

OUTPUT REQUEST

SECTIONAL FORCE:

• After edited all the setup for simulation then we have to set the output request that depends upon what the output we want in that simulation. Here we want to obtain the Sectional force in the rails at the location of the cross member to analyze the force obtained during the crash simulation.
• To create the cross-section by selecting the solver>create>SECT> then we want to create a movable frame in that cross-section and select nodes of origin, X-axis, and XY axis to obtain the normal N direction opposite from the crash direction X. This frame is created to the analysis of F3 force that is normal Z here they are considered as a sectional force while on the crash simulation.
• The below image shows the recommended nodes for sectional force and the created two frames

Fig: Cross-section

• A created cross-section and the frame system is shown as below,

Fig: Cross-section and frame system

• We want to initiate the system in section property and to mention the system number in Frame_ID of each recommended section. The cross-section for sectional force in the that node and the frame id is shown as below,
• In a movable frame, we want to select the origin node(N1), axis node(N2), and plane node(N3). The same node intimate in the system is required in the section node ID.
• A node selection and the axis point for the sectional force is shown below

Fig: Cross-section and frame ID properties

INTRUSIONS:

• To create the Intrusions on the B-pillar select one node on the pillar. By selecting the solver>TH>node> and select node and right-click on the node selection tab and enter the node number as 123409 it will consider that node for output observation. Then we want to define the skew system in the TH node properties.
• Hence it is created and that is shown below,

Fig: B-pillar intrusion

• To create the Intrusions on the hinge pillar select one node on the pillar. By selecting the solver>TH>node> and select node and right-click on the node selection tab and enter the node number as 123235 it will consider that node for output observation. Then we want to define the skew system in the TH node properties.
• Hence it is created and that is shown below,

Fig: Hinge pillar intrusion

• To create the Intrusions on the fuel tank region select one node on the pillar. By selecting the solver>TH>node> and select node and right-click on the node selection tab and enter the node number as 123495 it will consider that node for output observation. Then we want to define the skew system in the TH node properties.
• Hence it is created and that is shown below,

Fig: Fuel tank intrusion

• The three intrusion nodes that are selected at B pillar, hinge pillar, and fuel tank region are shown as below,

Fig: Intrusion points

• After creating the intrusions, as per the output request, we want to identify the Peak velocity of the inner node of the door therefore select one node on the door portion of vehicle and create the intrusion for that node. By selecting the solver>TH>node> and click the select Entity IDs and right-click on the node selection tab and enter the node number or pick the node by selection option it will consider that node for output observation.
• Select the Num_variables as default because it will give the default outputs for that node.

Fig: Door node

• Before running the simulation check whether the model is in good condition or not by using the model checker option. Now import the model into hypercrash and select quality>model checker>click run icon it will checks the total model and show the results. If any errors will appear after the completion of the model checker, clear the errors to run the simulation. Here the model checker is run completely and that is shown below,

Fig: Model checker

OUTPUT BLOCKS:

• Now the result is obtained in the respective given folder, open the folder, and analysis the errors like energy error and mass error. These errors are shown in the Engine Out file that is shown below,

Fig: Energy error and Mass error

• Here the result shows the two errors, energy error as -0.9 % and mass error as 0.000 %. An energy error should be in -5% is considered as better for simulation.
• The total number of cycles and the simulation time also noticed in that output and the values are shown below,

Fig: CycleTime

• Now open the hyper view and load Side_crash_final.h3d model file and select the apply option to open that model in hyper view. Therefore the model is opened and now to change the result type as Von Mises(s) to get the Von Mises Stress Contour Plot select the components and edit the averaging method as simple and click apply to get the animation of the vehicle crash on a rigid wall.

Fig: Vonmises stress Contour Plot and displacement plot

• Now the contour plot is generated click the mesh icon to visualize the deformation of elements in each node. Here if you see in the plot contour above is Von Mises stress, here the component going to crash with time as we run our simulation. It shows a different range of colors as stress increases on the component. Von Mises stress is a value used to determine if a given material will yield or fracture. It is mostly used for ductile materials, such as metals. Von Mises stress is computed and compared to the yield stress material. If the von mises is smaller than the yield stress the computed stress is the one used in order to compute the internal force of the element. The minimum and the maximum value of stress and displacement is shown below,

Fig: Stress value and displacement value

ENERGY PLOTS:

• To create the plot for each energy and absorbs that what was happening during the crash and how could the element gets deforming while applying some force. Now select hyperchart option that will give the empty graph as a display. Import the file side_crashT01 and click the apply option.

SECTIONAL FORCE:

Fig: Sectional force plot

From the above graph, we are observing the sectional force that is created on the parallel side of the cross member in the vehicle. A cross-sectional force is created to observe the force during the crash of a vehicle, the direction is defined by the moving frame through normal Z direction.

Each cross-section represents each skew system that should be indicated in that cross-section properties.

The graph shows the maximum value for one side of the sectional force is 8.03152KN at the time of 44ms and the other side is 3.85815KN at the time of 35ms this difference may appear due to the node differences and the frame direction acted on the force. In this result, the force we obtained is irrespective of the direction so positive and negative value is not considered it will change through the movement of the frame during crashing.

By comparing with these two sectional forces, sectional force1 is obtained more force of 8.03152KN compared with the sectional force2 of 3.85815KN this may depend upon the value-added mass in the vehicle.

INTRUSIONS:

B PILLAR:

Fig: B-Pillar displacement plot

• The intrusion is the process of identifying the displacement of some reference point or line or node. Here we are calculating the displacement of B-pillar by selecting one node in the B pillar. The node is selected and the above graph shows the displacement value of that node.
• A fixed skew is created in the other end of B pillar to observe the displacement of the intrusion point in B pillar node at the direction of the normal Z-axis that is defined in the system of skew.
• The maximum displacement point in the B pillar node is 204.188mm at the time of 78ms.

HINGE PILLAR:

Fig: Hinge Pillar displacement plot

• An intrusion is a process of identifying the displacement of some reference point or line or node. Here we are calculating the displacement of Hinge pillar by selecting one node in the hinge pillar. The node is selected and the above graph shows the displacement value of that node.
• A fixed skew is created in the other end of B pillar to observe the displacement of the intrusion point in hinge pillar node at the direction of the normal Z-axis that is defined in the system of skew.
• The maximum displacement point in the hinge pillar node is 493.6mm at the time of 78ms.

FUEL TANK REGION:

Fig: Fuel tank region displacement plot

• The intrusion is the process of identifying the displacement of some reference point or line or node. Here we are calculating the displacement of the fuel tank region by selecting one node in that fuel tank part. The node is selected and the above graph shows the displacement value of that node.
• A fixed skew is created in the other end of B pillar to observe the displacement of the intrusion point in the fuel tank region node at the direction of the normal Z-axis that is defined in the system of skew.
• The maximum displacement point in the fuel tank region node is 128.737mm at the time of 78ms.

COMPARING B PILLAR, HINGE PILLAR, AND FUEL TANK REGION INTRUSION:

By comparing these three intrusions such as B pillar, Hinge pillar, and fuel tank, 123235 node that is referred to as hinge pillar is getting the maximum displacement value of 493.6 mm that is also observed in animation file also. And the B pillar node of 123409 is obtained 204.188mm of displacement value during the crash simulation. The minimum displacement value is observed at the node of 123495 in the fuel tank region as 128.737mm at the time of 78ms during a crash on the rigid pole. This displacement of intrusion can vary that depends upon the mass added to the vehicle.

what can help to reduce Fuel tank intrusion

• To changing the material property ID is used to add the stiffness of material in that area of fuel tank region so that can help to reduce fuel tank intrusion.
• By including the additional cross-section member inside the fuel tank region is also acts as a resistive force of fuel tank region and the displacement also will take much lower compared with the default region so this can also help to reduce fuel tank intrusion.

PEAK VELOCITY OF THE INNER NODE OF DOOR:

Fig: Door node

• The intrusion is the process of identifying the displacement of some reference point or line or node. Here we are calculating the peak velocity of the door node by selecting one node in the inner node of door. The node is selected and the above graph shows the peak velocity of that node.
• A fixed skew is created in the other end of B pillar to observe the displacement of the intrusion point in the inner node of door at the direction of the normal Z-axis that is defined in the system of skew.
• The peak velocity is obtained in point of inner node is 3.57532mm at the time of 35ms.

ENERGY PLOTS:

Fig: Energy plot

• The above energy plot shows that increase in internal energy while the side area of the car is crashed on the rigid pole because of the contacts in the element it's getting raised, up to the simulation runtime when it completes the internal energy rises also getting stopped that will depend upon the deformation of the elements during a crash simulation. When the internal energy is observed due to contact of the car and a rigid wall. During the crash, there is a velocity is acted along with the car and it creates some energy that is observed as internal energy.
• During the crash simulation, the internal energy is getting raised up to 8914.57mJ at the time of 78ms, and at that stage kinetic energy also occurring between the car and the rigid wall. There is a decrease in the kinetic energy flow of 13337.4mJ at the time of 78ms because the velocity of the car is acted in a rigid wall that increases the internal energy so kinetic energy is decreased at the same level.
• The total absorption of energy is obtained when the car is crashed on the rigid wall and that energy is represented as total energy = sum of internal energy and kinetic energy. By equating the internal energy and the kinetic energy the total energy will remains in constant flow but here there should be a slight variation is shown in total energy because of the hourglass energy present during the crash simulation.
• Hourglass energy is observed in this graph that changes the total energy flow but here hourglass energy is observed as a very minimum value therefore it is negligible and it won't affect the total energy as more.

CONTACT ENERGY:

Fig: Contact energy plot

• A Penetration by the contact force is defined as contact energy here the contact energy is absorbed during the vehicle crashing on the rigid wall it will get deformation of elements and the penetration is also appear in the crash simulation.
• The force is created between the master and the slave node during the penetration that force and penetration are calculated as contact energy.
• Here the contact energy reaches the maximum point of 2412.65mJ when the time of 78ms.

TOTAL OUTPUT PLOTS:

• Therefore the total output plots are plotted and they are shown as below,

Fig: Total energy plots

LEARNING OUTCOME:

• Setup the model and create the card and their properties for side crash analysis using Hypermesh, Radioss, and Hypercrash.
• To know the types of force needed to calculate during the analysis.
• Analysis of energy plot after a side crash simulation is done.

CONCLUSION:

Hence the side crash simulation is done and has obtained the output plots for sectional force, Intrusion at B pillar, hinge pillar, and fuel tank region. Therefore the side area of the vehicle is crashed on a rigid pole hence energy error observed in this simulation is -0.9 % and mass error as 0.000 %.

Energy plots show the variable energy observed during the crash simulation and they are analyzed.

A crash of side area of car with a rigid pole and their impacts, forces, and intrusion values are obtained from simulation resultant plots so the study is finally done.