SIDE crash pole impact analysis using RADIOSS

SIDE crash pole impact analysis using RADIOSS

Objectives: To study force and energy received at different component of neon BIW and other objective is to create a global contact interface, rigid wall, add the masses to reach a target weight of 700 kg while getting COG about required range on neon BIW

Setup and Executions

• Open hyper mesh and choose RADIOSS interface
• Then import the 0000.rad file
• Check for correct unite system-> kg mm ms
• Open model in browser tab and select cards-> Begin card
• Check for the unite of mass ,length, time

connectivity check:

• After checking connectivity there was 3 free part
• which has to be connected with rigid
• after connections is done .we have to check for dependency
• we found 5 dependency which have to bee delect and check again for connections
• all part are concented properly

Interface:

• Create an appropriate interface with friction 0.2 and recommended parameters, Already a contract is defined in the model we have to delete that interface and to create a new interface type7 with recommended parameters.

Penetrations & intersections

• Now run the model analysis to check for errors and warnings.
• Make sure of no penetrations and intersections. If there is any penetrations correct it or simply use the gamin value to reduce the penetrations.

Rigid wall creation:

• An obstacle like cyclinder rigid is created beside side door with some parameters like frictions =0.1 and Dsearch as 1000 and diameter- 254 mm
• Rigid cyclinder is created by clicking on solver –right click- create- –plane then dialogue box will open and assign the required Values.

Initial velocity:

• We have to create a initial velocity in order to perform the crash. generally we have to give a initial velocity of 644 mm/ms
• We have created an initial velocity with 15.6464 mm/ms in VX-direction which is perpendicular to rigid wall

Creating Intrusions:

• We have to create an intrusions on B pillar, hinge pillar and fule tank to know the displacement of the particular wall into the occupant area. For this we have to create a fixed skew and make the respected node number in one position the below figure shows

Cross sections creation:

• We have to create the cross sections to know the force acting on those particular sections. we have to create sections on the following component , on cross member
• Go to solver –right click- create- sec-ok then a dialogue box will be open
• Before creating the cross sections we have to create a movable skew at the respected locations and add that skew in this dialogue box .then select the elements around that skew in at least two columns of the element thought out all sides as shown below. Select the grshel_id if we got the quard element at respected skew and select the grtria_id if we got the element at respected skew. Assign some value to that card such as Isave as 0,delta T as 0.1 alpha as 0.65 and iframe as 12.perform the same method for other components and create the required cross sections

Mass addition & C.G:

• Initially the model has a weight of 166 kg we have to add the mass to reach a target weight of 700 kg to get the COG about the required range we have to add the Mass at the floor of the BIW in order to get the COG at required range

Creating output Blocks:

• Creating output block for intrusions and cross sections

Runtime and time step:

• The run time is set to 80 ms and time step is 0.5 ms

Model checker:

• Right click on error and select Run to Determine the error and the Error tab opened to view errors
• After completing pre-processing the model is checked through model checker.
• If no errors, proceed for the simulations run else solve the error and then run simulation

Run the Simulations :(by using Radios as solver )

• After creating all required out puts in hyper mesh, we have to run the simulations By using Radioss (solver) keep the export options as all run options as analysis , run number as 1 , options as –nt 4

Processor (solver):

• From Front_crash_0001.out file, the Total number of cycle was 80001. The energy error is -2.3% which is acceptable limit. The mass error which also less than 5% it is acceptable. The run was “normal terminated’ which implies the processor successfully completed. There was no sudden changed in energy as well as in error. as shown below

Post-processing:

• Observe the animation run and analyse the change occurring in elements and their reactions for a period of 80ms
• Similarly analyse using contour ( select contour icon on toolbar)
• Select result type as displacement or Vonmises , averaging method as simple also use maximum and minimum measurement plotting using measures icon in the toolbar
• displacement
• von mesis

Plot:

• plot graph for Global variable which includes – hourglass energy, Total Translational energy, internal energy, Kinetic energy, contact energy
• create graph for intrusions
• create graph for cross sections

Energy:

• the hourglass and the contact energy shows only the peak of energy with respect to time
• The hourglass and the contact energy is not physical energy and it needs to be reduced.
• From the above graph the kinetic energy and internal energy decreases and increase respectively in a gradual manner. There are no sudden fall or rise in energy which means there is no much error in simulations. The contact energy increase gradually and hourglass energy is almost negligible. Moving to next step the mass and inertia before and after is same. Which means we can to post processing?

Intrusions:

• • The purpose of intrusion to know the displacement of the node in the occupant area.
  • The below figure shows the graph of maximum displacement with respect to time

• node-2027326-fuel gas region-blue
• node-123610-pillarB region-red
• node-123584-seat region-green

• There are 3 intrusions to observe installed to observe deformations. All this point is in region.
• After the impact, the deformations increase gradually andat time t =79.5 ms the maximum deformations of t= 79.5 ms the maximum deformations of 800 mm which is very high. In order to reduce the deformations stiffer material should be introduced
• This is most critical area since the fuel may leak or catch fire. So it must be protected from effect of impact. From the above graph the maximum deformation is observed at t= 79.5 ms which is 576 ms /mm. Which is very high?

Cross- sections

cross member

• The below graph shows total result force on one and two cross member

• The cross sections 1 are near driver’s area. After impact at there is increase in force gradually at time T=64 ms the maximum force is 4.7KN. And there is decrease in force
• The cross sections 2 are near B pillar area. AT time t=63 KN. And there is decrease in force. There is more jerks on the first cross member than second

peak velocity

• The initial velocity of the car is 15.64 m/s As the car impacts on the pole there is sudden drop in velocity. the decrease in velocity is due to decrease in kinetic energy . Due to collision there is increase in velocity in the maximum velocity of 16.21 ms/s and then it its start decreasing

How to reduce intrusions near fuel tank

In order to protect the fuel the tank material should be stiffer . There should be more component before the tank like cross member i.e so that transfers the force can grain cross member not the fuel tank so there must be more component in the door . there can be more cross rod or beam introduced in the door which absorbs the forces and there will less deformations at fuel tank

Conclusions:

1. The force is transferred through cross member to the other side.
2. The cross sections at B pillar is expressing maximum forces due to the pole is placed near the B pillar
3. The maximum intrusion is at B pillar followed by area near fuel tank
4. The stiffness should be increased of the component near fuel tank so there will be less intrusions

link for file

https://1drv.ms/u/s!AlDYq9nTGAGCiQ5VQSa6M8DJ2j2M?e=aXcBSe