Assignment 6-Frontal Crash Simulation Challenge

FRONTAL CRASH SIMULATION OF DODGE NEON CAR

Project 1 – Crashworthiness Analysis Using Hypermesh, Radioss and HyperCrash

Aim:

• To perform the crash analysis on the frontal section of the car and to check where the stresses are acting on it.
• To check the unit systems and change if necessary
• Create an interface of Type 7 with the friction value of 0.2 and other parameters.
• Making sure there aren’t any penetrations
• Correct rigid bodies for any issues
• Create a rigid wall with friction 0.1.
• Compare the model weight with the full-scale 300k nodes model and use added masses to reach the target weight of 700kg while getting CG about the required range.
• Give an initial velocity of 35 mph.
• Use a model checker to ensure good quality.
• Give the Time-step: 0.5 microsecond.
• Give Run time as 80 ms.

Output Requests:

• Sectional force in the rails at location of indicated node 174247.
• Axial force received on the rails from bumper.
• Shotgun cross sectional forces.
• A pillar cross section.
• Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
• Intrusions on the dash wall 66695,66244.

ABSTRACT:

The crash test is a virtual reconstruction that replicates the same forces and speeds that would occur if the vehicle was to be involved in an actual crash. In this type of testing, since nothing is physically impacting the Body-in-White (BIW), no physical deformation or damage occurs to the body’s structure, allowing multiple crashworthiness tests to be conducted in succession. This type of simulation is an integral part of the design process and can help save both time and money since it can be implemented instead of costly, destructive testing programs.

For this project, the case setup and simulation are to be done in Hypermesh and Hypercrash, whereas Hyperview and Hypergraph 2D will be used for post-processing. Hypergraph will be used to plot energies, Von-Mises stresses, plastic strains, acceleration curves, and force and Hyperview will be used to view the simulation.

As part of the process, we are to create a rigid wall, check penetrations, assign an initial velocity of 35mph, carry out mass balancing to ensure the total weight comes to 700 kgs, and finally, create sections, intrusions, and accelerometers as part of the output request requirements.

A. Frontal Crash

A crash test is a form of destructive testing usually performed in order to ensure safe design standards in crashworthiness and crash compatibility for various modes of transportation or related systems and components.

B. Various Crash Test

A crash test is a form of destructive testing usually performed in order to ensure safe design standards in crashworthiness and crash compatibility for various types of vehicle like small, medium and heavy-duty and its related systems and components for the sake of getting the performance of the vehicle under the different conditions of the crash at different angles with taking certain object like a rigid wall, cables specially three-strand cable, concrete barriers, guardrail systems etc. It will be performed either by numerical simulations or experimentally. The figure below illustrates different types of crash test generally used.

• Frontal Impact test- In this test a fully front structure of the vehicle collides with another object like another vehicle, rigid wall etc. at a given speed.

• Offset Test- In this test, only a part of the front portion of the vehicle strikes on some barrier usually a vehicle at a given speed.

• Small Overlap Test- In this only a small portion of the vehicle strikes an object like a tree, pole or if a car were to clip another. This situation loads a maximum value of force into the vehicle structure at a particular given speed. This test usually comprises 15% to 20% of the front structure.

• Side Impact Test- In this test sometimes the vehicle is in static condition or in dynamic and another vehicle or an object collide at the side surface having some speed.

• Roll-Over Test- In this test a vehicle is in rollover condition having a certain angle by which they test (specifically the pillars holding the roof) to support itself in a dynamic impact. It is also done for the static crash testing condition.

• Roadside Hardware- These are performed to ensure that the crash barriers and crash cushions will protect vehicle occupants from roadside hazards.

• Old Versus New- In this, an impact is done between an old car against a new car and the big car against a small car it is performed to show the advancements in crashworthiness.

Crash tests are conducted under rigorous scientific and safety standards. Each crash test is very expensive so the maximum amount of data must be extracted from each test. Usually, this requires the use of high-speed data acquisition, at least one triaxial accelerometer and a crash test dummy, but often includes more. A crash test is much important which helps in minimizing the losses such as deaths, injuries, and property damages from vehicle crashes on the roads.

In this Project, we must perform the Frontal crash of the vehicle. Frontal impacts are the impacts undertaken against the solid barrier with precise speed. The test requires the front portion of the vehicle to impact the barrier.

In the New Car Assessment Program (NCAP), passenger vehicles are crashed at 35 mph into a rigid barrier that covers the full width of the vehicle. The Institute runs offset frontal tests instead of full-width frontal tests. In an offset crash only one side of a vehicle front end, not the full width, hits the barrier.

C. HOW CRASH TESTING WORKS

A crash test is a form of destructive testing usually performed in order to ensure safe design standards in crashworthiness and crash compatibility for various modes of transportation-related systems and components.

Crash test dummies have been the subject of public service announcements, cartoons, parodies, even the name of a band. Real crash test dummies, however, are true life-savers as an integral part of automotive crash tests. Even though cars get a little safer each year, and fatality rates are declining, car crashes are still one of the leading causes of death and injury in the United States.

One of the reasons cars have been getting safer is because of a well-established testing program.

The dummies contain three types of instrumentation:

D. Accelerometers: These devices measure the acceleration in a particular direction. This data can be used to determine the probability of injury. Acceleration is the rate at which speed changes. For example, if you bang your head into a brick wall, the speed of your head changes very quickly (which can hurt). But, if you bang your head into a pillow, the speed of your head changes more slowly as the pillow crushes (and it doesn't hurt).The crash-test dummy has accelerometers all over it. Inside the dummy's head, there is an accelerometer that measures the acceleration in all three directions (fore-aft, up-down, left-right). There are also accelerometers in the chest, pelvis, legs, feet and other parts of the body.

Load Sensors: Inside the dummy are load sensors that measure the amount of force on different body parts during a crash.

Movement Sensors: These sensors are used in the dummy's chest. They measure how much the chest deflects during a crash.

E. Crashworthiness Requirements:

The vehicle structure should be sufficiently stiff in bending and torsion for proper ride and handling. It should minimize high-frequency fore-aft vibrations that give rise to harshness. In addition, the structure should yield a deceleration pulse that satisfies the following requirements for a range of occupant sizes, ages, and crash speeds for both genders: Deformable, yet stiff, front structure with crumple zones to absorb the crash kinetic energy resulting from frontal collisions by plastic deformation and
prevent intrusion into the occupant compartment, especially in case of offset crashes and collisions with narrow objects such as trees.

• Short vehicle front ends, driven by styling considerations, present a challenging task to the crash-worthiness engineer.
• Deformable rear structure to maintain the integrity of the rear passenger compartment and protect the fuel tank.
• Properly designed side structures and doors to minimize intrusions in side impact and prevent doors from opening due to crash loads.
• Strong roof structure for rollover protection.
• Properly designed restraint systems that work in harmony with the vehicle structure to provide the occupant with an optimal ride down and protection in different interior spaces and trims.
• Accommodate various chassis designs for different power train locations and drive configurations.

PROCEDURE:

• Check for UNIT SYSTEM
• Import model in HYPERCRASH
• Check for penetration and intersection
• Add masses to reach a target weight of 700kg
• Export changes file and import in HYPERMESH
• Create Interface contact's
• Create interface contact between component and bumper
• Create a rigid wall
• Add velocity to the nodes
• Create cross-section's
• Create acceleration nodes
• Create springs to check deflection
• Assign property to springs
• Create TH for section forces, intrusion springs, interface contacts
• Create cards
• Model checker

unit system used for analysis is "kg mm ms".

1. Imported Model:

Imported Geometry

2. CHECK FOR UNIT SYSTEM:

In the data, we have two files

1. Neon_front_0000.rad (starter file) stores information about:

• Nodes
• Load Conditions
• Velocity
• Boundary Conditions, etc.
• Basically, it is an ASCII (American Standard Code for Information Interchange) file that contains the model information.
• The starter file should always end with 0000.rad.

2. Neon_front_0001.rad (engine input file)

The engine File stores information about:

• Simulation Runtime
• Simulation Speed control parameters, such as No. of Animation Files, No. of Time History File, Size of the history file and Animation frequency, etc.
• Basically, it is an ASCII (American Standard Code for Information Interchange) file that describes the run controls.
• We can also edit the Engine File directly through the Control Cards.
• The starter file should always end with 0001.rad.

unit system used for analysis is "kg mm ms".

Checking Unit System In Starter File

• I will do some of the setup in Hypercrash first, then move to Hypermesh for the rest of the setup

RADIOSS User Profile - Opening HyperCrash

3. IMPORT STARTER FILE IN HYPERCRASH:

• Select Neon starter file and drag it to hypercrash application to open the model

Model Imported In HyperCrash

4. CHECK FOR PENETRATION AND INTERSECTION:

• Penetration is defined as the overlap of the material thickness of shell elements, whereas Intersection is defined as elements that pass completely through one another. All models and especially impact models should be checked for penetrations and intersections and they should be De-penetrated to ensure the integrity of the model. Penetrations adversely affect results and should be removed.
• To check penetration and intersection: Go to Quality>> Check all solver contact interfaces >> Select parts > Click on check penetration.

Checking for Penetrations

Zero Penetrations

• We can clearly see from the above figure there are no penetrations and intersections are present in the model.

5. Compare the model weight with the full-scale 300k nodes model and use added masses to reach a target weight of 700kg while getting CG about the required range.

• A vehicle’s centre of gravity, or CG, is the theoretical point where the sum of all the masses of each of its individual components effectively acts. In other words, from a physics perspective, a vehicle behaves as its entire weight resides at this one point. Carrying weight up high, such as a panoramic sunroof will raise a vehicle’s CG while placing heavy subsystems low in a vehicle, such as a battery pack, will work to lower it. Lower is better from a handling standpoint, as it reduces weight transfer during cornering and braking, and it also reduces the propensity to roll over.

MASS ADITION & POSITIONING OF COG:-

• Mass balancing:In order to maintain the COG of a car, we must add mass for the given components, In the given model here are so many parts are missing because of the node limit in the student version
• To check the COG, Go to menu >> Mass >> Balancing >> Show CG point

• It is showing that the total mass of the body is 188.2 kg which is 700-188.2 = 511.8 kg less than our target mass.
• Before adding mass check the CG, to check the COG of the body we have to click on the specs icon as shown below.

COG when it is imported

Creating MASS

• Current weight: 188 kg
• Target weight: 700 Kg
• We must add the mass in such a way that the Centre of gravity is exactly in the middle of the Cross Beam to simulate the real-time model.
• We are only worried about the position of the COG (X and Y axis) and not the height (Z-axis).
• We use Type 1 Mass, where mass is distributed on each node of the selected group.
• also we can use TYPE 0 mass where mass is added to each node of the group like suppose you have set the 0.1 kg for each node then if you select say 1000 node at a time then total mass will be added as (0.1*1000=100 kg).

Creating TYPE 1 MASS

• I have added 7 masses as shown below, which will achieve target mass of 700kg

• First, Assign Added Mass value and then, In grnod_ID Support, right click >> select in graphics >> select the nodes. Do this for every added mass
• We should add mass in such a way that the COG comes to middle.
• The initial structure of the BIW Model is 188 kg.the mass is added to the structure to achieve 700 kg mass like a full car model.The mass is added in such a way that COG of the body should lie near the driver seat .so mass is distributed as front seat having mass of 70 kg each.The backseat is having 224 kg.38 kg is distributed in the front rails for the engine component.In order to adjust COG 110 kg is adjusted at bottom of B pillar.

Total 7 MASSES are created

• After adding mass we have successfully balanced the weights to a target length of 700kg and COG also moved to recommended position.

COG moved to recommended position after adding MASS

6. EXPORT HYPERCRASH FILE:

• Export the rad file changes made in hypercrash and import the same file in hypermesh to make other changes
• For that Go to File >> Export >> RADIOSS and save the file. I have saved the file with name “neon_COG_modified_0000.rad”.
• Now open this same file in hypermesh

7. CREATE SELF CONTACT:

In this case, the Type 7 Contact Interface is defined. Interface TYPE7 is a multi-usage impact interface, modelling contact between a master surface and a group of slave nodes. It is also possible to consider heat transfer and heat friction.

All limitations that were encountered with interfaces TYPE3, TYPE4 and TYPE5 are solved with this interface:

• A node can at the same time be a slave and a master node.
• Each slave node can impact each master segment; except if it is connected to this segment.
• A node can impact more than one segment.
• A node can impact on the two sides, on the edges and on the corners of each segment.
• It is a fast search algorithm without limitations.

The main limitations of this interface are:

• Time step is reduced in case of high impact speed or contacts with a small gap.
• It does not work properly if used with a rigid body at high impact speed or a rigid body with a small gap.

It does not solve edge to edge contact (to solve this, /INTER/TYPE11 should be used along with TYPE7).

• At the begining there was 6 interfaces of type 7 used to the BIW structure .but there was no proper connection present in the whole model so for the betterment of the model we have to deleted those interfaces present and have to create a new interface for the whole model for proper connection.

TYPE 7: NODE TO SURFACE

This interface simulates the most general type of contacts and impacts. TYPE7 interface has the following properties:

• Impacts occur between a master surface and a set of slave nodes, like the TYPE5 interface.
• A node can impact one or more master segments.
• A node can impact on either side of a master surface.
• Each slave node can impact each master segment except if it is connected to this segment.
• A node can belong to a master surface and a set of slave nodes.
• A node can impact the edge and corners of a master segment. None of the previous interfaces allows this.

Type 7 contact

• The recommended properties are as follows

Recommended Properties

Selecting all the components for new interface

• We need to give in the Slave nodes and the master segment. Since we are defining a Self-Impact in the model, the Slave and Master segments for this contact will be the entire given model. So, we then select all the nodes for both segments respectively as shown below.
• Also, delete all the other components under Groups as they are not assigned to any part in the model

Properties are assigned to TYPE 7 contact

• To check whether master and slave nodes selected properly you can review them as shown below

Slave and Master nodes selected Perfectly

8. CREATE RIGID WALL:

• A rigid wall is a nodal constraint applied to a set of slave nodes in order to avoid the node penetration to the wall. If contact is detected, then the slave node acceleration and velocity are modified. Mainly to constrain the movement of a moving body after impact, we will be using a plane wall. An infinite plane wall is a plane that extends to infinity. It is defined with two points.
• Rigid wall entities provide a method for treating a contact between a rigid surface and nodal points of a deformable body. In the Radioss user profiles, rigid walls can be created in the Model and Solver browsers.
• To create an RWALL: Go to Slover browser >> Create >> Rwall >> Plane
• We need a reference node to create an RWALL so for that we are creating a temp node in the middle of bumper
• After that translate that node to create some gap between car and wall which will be created at the translated node or you can manually create a gap by putting the increased value of the temp node in the x axis as shown in below.

Temp node is created

Co-ordinates X, Y and Z values

• It is a Shell element with no thickness (gap) and infinite thickness.
• A search tolerance is given (optional) so that the nodes within the range will be taken as slaves.
• We are going to create an Infinite plane type Rigid wall.
• Enter the coordinates of the Temp node [XM, YM, ZM] >> Enter the Direction of the Normal [-1, 0, 0] >> Select GRNOD_ID 1: set of displayed nodes >> Dsearch: 1000/1500

The rigid wall is facing opposite to the car so the normal is on the negative X-axis that is why the value of normal x is kep as -1.

• We must provide frictional parameters for the rigid wall when the slave nodes come in contact
• Friction type [Slide] = 2: Sliding with friction
• Frictional Coefficient [FRIC] = 0.1
• The D-search distance we can use around the range of 1000 mm. All the Nodes within this distance will be considered as salve nodes for the contact between the car and the Rigid Wall.

RWALL is created

• but as spoken earlier there is no gap present in the bumper and the rigid wall as the co ordinates of the temp node is given which is located in the mid bumper ...so here we can create a gap between the bumper and rigid wall manually by increaing the value of X co ordinates of the temp node as shown in fig.

gap is created

• so here instead of putting the exact value co ordinates of temp node we increased a liitle bit in the value and for that reason the rwall is differ from the location and create a gap between those two.

9. CREATE VELOCITY:

• Initial velocity is 35 mph.
• Converting 35mph into ms
• We get 1mph = 0.447 ms therefore 35mph = 15.6464 ms
• The initial velocity (Vi) is the velocity of the object before acceleration causes a change. After accelerating for some amount of time, the new velocity is the final velocity (Vf).
• Go to solver browser >> Create >> Boundry conditions (BC) >> Inivel

Creating Initial Velocity

Selecting all the nodes

10. CREATE SECTIONAL FORCES:

• We need to Create Sections at A-Pillar, Shot Gun, rails and the Bumper in order to Study the sectional forces.

• We should know how the forces are transmitted from the Bumper to the Dashboard and the rate of deformation. It is done in order to ensure the safety of the passenger.
• Certain components will crash (deform) more than the other so that the forces are distributed correctly leaving very little force left to transmit inside the cabin.
• To create a section and Frame Go to Slover browser >> Create >> Section >> SECT

creation of SECT CARD

11. FRAME CREATION:

• Before creating sections, we should create frames. The Frame is created to make local coordinates of the section.
• To create the Frame, Right Click on the Tab Area in the Solver Browser >> Click Create >> FRAME >> MOV >> Select the Nodes So Create an Axis >> Create.
• Remember, while creating local coordinates, select the nodes in such a way that the Z- Axis should be in the direction of the initial velocity applied.

• Now create sections and assign each FRAME to each Section accordingly.
• in here i will show the workdone for the left A pillar.
• first create a SECT CARD for left A pillar like shown in previous fig.
• Create a movable frame for left A pillar.

selection of 3 node for making frame

• for creation of frame you have to select 3 node ...for the sect card you have to select again those particular 3 node(N1,N2&N3).this 3 node taken as reference frame node for calculating the forces across the section.

same value of N1,N2 & N3

• Then under the FRAME_Id you have to select the frame you had made earlier.

selection of frame id

• Put the value of delta T as 0.1 and alpha as 1.64 and iframe value set to 12.
• then for the cross section under grshel id set two rows of elements as shown.

Selecting elements for grshel_id

• For grshel_id select a section of elements on a component where we should calculate forces going through them.
• Remember, the plane created at the section must be perpendicular to that component.
• Now do the same for the rest.

All the required sections are created successfully

12. CREATE ACCELERATION NODES:

• Creating Accelerometer at both sides of the B pillar.
• An accelerometeris a basic technology that converts mechanical motion into an electrical signal. It is an electromechanical device that measures acceleration forces, whether caused by gravity or motion.
• Go to Model browser >> Create >> Accelerometer >> Select node

Two accelerometers are created

13. CREATE SPRINGS(i.e INTRUSIONS on the dash wall):

• Intrusions here means how much displacements the driver is facing near the brake and acceleration pedal.
• We are planting Spring elements to study the intrusions (forces inside the cabin causing deformation/rupture).
• Create 2 parallel spring elements from the indicated nodes (66695,66244) till the Crossbeam.
• Springs can be created from the 1D Panel > Springs
• Select the node at required node id as shown below and then, select another node on other end to create spring, this is done to see how much the cabin is crushing during crash

Selecting node for spring

Springs are created at required nodes

• Now create a property as shown below and assign that property to those springs.

Spring Properties

14. Delete existing TH and Create New Cards

• Delete all the unnecessary TH files and create the Time History files for the boundary conditions that we have created for the frontal crash model.
• This will help us reduce some time for simulation as the solver only calculates TH for required outputs

Deleting Unnecessary TH's Accelerometer's TH

Interfaces TH Rigid Wall TH

Section's TH

15. Edit Cards

• Before running the simulation check all these cards and assign the values accordingly

ENG_ANIM_DT Card ENG_RUN Card

ENG_DT_NODA Card

16. Creating Output Blocks

• Output blocks contain the data which we need to create graphs after the simulation
• Therefore, we need to create 5 different output blocks for different sets of data
• Print only the required output blocks as this makes the simulation fast.

Output Block Properties of sectional force, TH, AND INTERFACES

Output Block Properties of Accelerometers and Springs

17. Errors

• After running the simulation in tools >> Model Checker.
• We can easily identify and delete Unused sets and Empty sets using tools >> empty or unused option
• Similarly, delete unused translational joints and spherical joint.
• Also, assign property for the spring.
• Check if the accelerometer nodes are selected perfectly or not.

you also have auto correct option to get rid of the error in model

18. DRY RUN (Simulation)

• Sometimes, the errors are not shown in Model Checker
• In this case we should run a dummy simulation to know the errors
• To do that go to ENG_RUN and change Tstop value to 0.
• Now run the analysis as shown below
• It will run in quick time and points out all the errors
• Note down all the errors and rectify them
• After rectifying all the errors change the Tstop value as required and run the analysis
• This Dry Run is useful for Simulating Bigger Models
• Since there were no errors during the dry run, we can now run the actual simulation
• Change Tstop to 80 and run the analysis

dry run completed with 0 error

19. ANALYSING THE OUTPUT FILE

• The next step is to carry out energy error and mass error checks and this is done by checking the RADIOSS engine output file. This can be accessed from the same directory as the starter and engine files and is denoted by the '.out' extension. The file in question contains '_0001.out' and can be accessed using any text editor - such as Notepad.

Engine Output file

• As we can see, the energy error is -1.3%. It is definitely acceptable within range of -10% to +5% error. In addition to that, the mass error is 0.04154, which means that a negligible quantity of mass of was added during the simulation, possibly for the sake of time step control/stabilization. It is a rather low amount so it's still acceptable.
• Total Simulation Time: 2549.51 seconds, which is 42m 29 seconds.
• of cycles: 80001

20. SIMULATION ANIMATION

• To view the simulation, we can switch to Hyperview through the client selector.
• In Hyperview, we will need to import the h3d variant of the file.
• Then the contour panel is opened, which appears as shown in fig below. In which the parameters to view the simulation are selected. Such as: result type:In terms of Displacement, von misses stress etc. then selecting the components & apply.

Frontal Crash Analysis - Displacement

Frontal Crash Analysis - Von Mises Stress Side View

• From the simulation, we can see that. Initially, the bumper starts crushing then the bumper forces are transferred to the left and right rail then from the rail forces are transferred to A-Pillar LH and RH. In each stage, the forces are going to reduce because energy is absorbed in each stage. Because of no engine blocks, suspension system and tyre etc the car BIW is going to go down at the end of the simulation
• From the Von Mises stress plot, we can say that the stress distribution is quite good in the vehicle after the crash. There are very few areas where we can see stress concentration. Generally, the stress is more in bumper region as it is the first point of impact.

21. GENERATING THE PLOTS

• After generating the simulation, we can then go ahead and generate the plots. Using the same client selector, we can switch to Hypergraph2D. In the Hypergraph client, we are asked to import the required file, which is the T01 (Time history file) variant of the file.

A. Global Variable Graphs: Energies

INTERNAL ENERGY AND KINETIC ENERGY:

• The changes in kinetic and internal energies occur at the exactly when BIW body comes in contact the rigid wall. Obviously, the BIW loses kinetic energy throughout the simulation due to decrease in velocity. At the same time, it absorbs the forces, and this results in an increase in internal energies, and as a result, the deformations also occur. Thus, the total energy in the system is almost constant at 80000 J and due to some energy loss which we can see in energy error, there is some decrease in total energy.
• From the above graph, we can see that the Hourglass energy is almost negligible since we have used Improved integrated element formulation (QEPH)

B. Contact Energy Graph

• Contact energy is a type of energy that is formed when one element meets the other or neighbouring elements. The opposing force created by this element forms the contact energy. In this case, it increases after 5 ms, at this point the model starts deforming in such a way that penetration of nodes occurs. When certain regions of the model press on themselves, buckled elements are forced into contact.
• The increase in contact energy affects the overall energy of this system, which is why there is a decrease in the total energy over the course of the simulation. it is a negligible decrease though. The magnitude of contact energy generated is much lower.

C. Rigid Wall Forces:

• You can see that there are two peaks in forces at 3ms and 16ms respectively, these peaks are due to the force caused at the bumper at the beginning of the simulation. As the simulation goes on the RWALL forces decreases and again it increases slightly at the end of the simulation.

D. OUTPUT REQUESTS

SECTIONAL FORCES - On RAILS:

• If you see the top view of the simulation, left Rail which is left to the screen deforms more in the beginning at arount t = 16ms and cross section 4KN/mm
• For right Rail the peak value is at t = 16ms and cross section at almost 16KN/mm
• The force acting on the rail is the force transmitted by the bumper during the crash.
• At last, if you observe carefully, the car is tilted towards right i.e., towards right Rail, that’s why the force increases again at t = 35ms at 13 KN/mm cross section.

E. On Shotguns:

• The Force that occurred at the shotgun is the force transmitted from the rail section. The force propagation is not the same at both the rails and hence the amount of deformation at both the shotgun sections are different. Once the Compressive force reaches its maximum value it starts to deform rapidly. Therefore, the Compressive force is decreasing as referred from the graph.
• As the crash happen continuously, the shotgun will meet the Rigid wall as shown in Animation, the rigid wall also exerts the force directly on to the shotguns and hence there is an increase in the Sectional force as seen in the graph.
• The force in the right Short gun is more linear compared to the sharp hills in the left Short gun .
• The maximum cross-sectional force at Left Shotgun is 5 kN/mm at t=30ms whereas the maximum cross-sectional force at Right Shotgun is 2.1 kN/mm at t=70ms.

F. On A-Pillars:

• If you see the simulation left A-pillar is on the left side and right A-pillar is on the right side to the screen.
• The maximum cross-sectional force at the left A pillars are at 8.5 KN/mm at 58 ms and at right a Pillar is 2.1KN/mm.
• when the car hits the rigid wall, there will be some amount of force coming into the A-pillar at both sides. These forces coming to the A-pillar are nothing but the force transmitted from the rail and the shotgun. The force flowing into the LH and RH of the A-pillars will not be equal and hence the deformation of the elements will differ accordingly.
• During a frontal crash, the sectional force reaching the A-pillars are coming in from the rails and shotgun, hence the force at the A-pillars will be less when compared to the front sections.

G. Intrusion Springs:

• here we can see the afte the frontal impact of the BIW the intrusion is recorded in the form of displacement.This instrution node 66695 & 66244 are near the driver brake and acceleration pedal .As there are no other components in the front section of the vehicle like the absence of Engine,Radiator etc there is huge deformation recorded at this instrution node .this can be fixed after adding the missing parts near the front section & the value is come in negetive as the displacement is happened in negetive X axis direction as well as the velocity of the springs.

• As we all know that an Acceleration is the rate of change of velocity. To measure the acceleration, we have placed the accelerometer near the Rocker of B-Pillar on both sides. From the above graph, we can see that initially, the acceleration is constant before the vehicle hitting the rigid wall.
• Once the Car hits the rigid wall with the initial velocity, The acceleration of the vehicle during the crash is not constant across the structure.this is due to the retardation of the vehicle at various sides at various velocities. The front of the vehicle slows down immediately as it hits the rigid wall, while the rest of the structure decelerates at a slower rate as seen in the graph. As seen from the graph there is a sudden increase in the acceleration, this might be because of some vibration that occurs during the crash with respect to the point where the accelerometer is placed.
• Maximum acceleration at LH = 0.65mm/ms2 at t=56 ms
• Maximum acceleration at RH = 1.22 mm/ms2 at t=75 ms

Learning Outcomes:

• Importance of COG and its recommended position
• Learned the topics of the interfaces and values that are recommended for the project.
• Created Initial Velocity, accelerometers, and Intrusions, Frames, Sections, and local co-ordinates.
• Created time history cards and output blocks
• Rectified errors in model checker
• Simulation is run, animations are captured, and graphs are also plotted

Conclusion and observation

• All the required objectives are fullfilled according to the question
• Frontal crash analysis was carried out on the given front half of a BIW model of the Dodge Neon as per the given requirements. The output requests were also generated after the creation of cross-sections in each of those regions. Acceleration and intrusion values were also measured at certain points of the model.
• But it does not show the actual simulation since many components is missing in the front section which absorbs the most amount of energy.
• from acclerometer it is clear that there are more jerks on the right side then the left.
• From all this data we can say that the Dodge neon’s Crumple Zone absorbed most of the forces and it transformed less forces to the cabin or safety cage. From the less intrusion values, we can say that the cabin is very safe during crash.