Week-7 Head Impact

WEEK 7 CHALLENGE - HEAD IMPACT

AIM:

To perform the Head Impact simulation by following three cases.

GIVEN:

SIMPLE HEAD MODEL:CASE 1

PEDESTRIAN HEADFORM MODEL:CASE 2

HOOD MODEL:CASE 3

DELIVERABLES:

1.The impact simulation of a simple head impact with the Rigid wall.

2.The impact simulation of the Headform provided with the Rigid wall with the Stress / Strain plots and acceleration plot.

3.The impact simulation of the head form with the Hood with the Stress / Strain plots and acceleration plot. For the hood, you can use Aluminium.

4.The Stress / Strain plot from the Rigidwall simulation should be compared with the Stress / Strain plot from the Hood Simulation and there should be a detailed explanation if there is any difference in the plots.

PROCEDURE:

CASE 1:SIMPLE HEAD IMPACT WITH RIGID WALL

• Open the .k file of simple head impact model in LS dyna Pre-post
• Create a section for the simple head with Elform 2 and Thickness 2.5mm

• Create a material for the Head element

• Assign the MAT and SECTION card to the part
• Create a Rigidwall to impact the Simulation of simple head to Rigidwall.To create a Rigidwall Go to Create entity_Rigidwall and Create with Planar

• Now we have to apply initial velocity=40kmph i.e. 11.11mm/ms to the shell element.Create a node set for the Head shell element in Create entity.

• For contact we will choose the AUTOMATIC_SINGLE_SURFACE_CONTACT

Control Termination:

This card is enabled to specify the end time of simulation,which is 20ms.

DATABASE CARD

The time step value of 0.5ms is given for BINARY_D3PLOT and DATABASE_ASCII Option for GLSAT,MATSUM,NODOUT,RWFORC

DATABASE_EXTENT_BINARY:

This card is used to compute the elastic Strain in the model by keeping STRFLG as 1

The model has been checked error and ready to run the simulation, file is saved as .k extension and it is run in LS Run by getting a normal termination

CASE 2:PEDESTRIAN HEAD MODEL WITH RIGIDWALL

• In this case we will perform Head model impact with rigidwall at 50 degree rotation of the model
• Create a New .k file and Define a Transformation

• Include the Pedestrain Head file into the New file by Create a Include Transform Card

TRANID is the ID we have create before as DEFINE_TRANSFORMATION

• Material and section has been already assigned so next we have to create a Rigidwall as we have done previously on the CASE 1.
• Assign the velocity in X and Z axis as the head is in 50 degree rotation.

• The output data we can applyin same as CASE 1 i.e. TERMINATION = 20ms , D3PLOT - 0.5 and also for ASCII_options.

The model has been checked error and ready to run the simulation, file is saved as .k extension and it is run in LS Run by getting a normal termination

CASE 3: PEDESTRIAN HEAD MODEL WITH MESH HOOD

• Open a new file and proceed like Case 2
• define Transformation and rotate at 50 degree and Include the pedestrian file by go to INCLUDE_TRANSFORMATION.

• Here we are going to use a Different to Include Meshed_Hood file by creating INCLUDE card

• Assign Shell Section for the Hood with thickness 1.5mm and Aluminium Material Property

CONTACT CARD:

• Here we are using Automatic Surface to Surface Contact Card and Keeping head model as Slave and Hood as Master

SSTYP and MSTYP as 2 (EQ.2: part set ID)

• Velocity Card as been create as same as CASE 2.
• The output data we can applyin same as CASE 1 &CASE 2 i.e. TERMINATION = 20ms , D3PLOT - 0.5 and also for ASCII_options.

The model has been checked error and ready to run the simulation, file is saved as .k extension and it is run in LS Run by getting a normal termination

OUTPUT RESULTS:

CASE 1:SIMPLE HEAD IMPACT WITH RIGID WALL

STRESS:

STRAIN:

GRAPHS:

1.ENERGY

2.HIC

CASE 2:PEDESTRIAN HEAD MODEL WITH RIGIDWALL

STRESS:

STRAIN:

GRAPHS:

1.ENERGY

2.HIC

CASE 3: PEDESTRIAN HEAD MODEL WITH MESH HOOD

STRESS:

STRAIN:

GRAPHS:

1.ENERGY

2.HIC

• Comparing the three cases Stress value of Head impact with rigidwall is higher than pedestrian Head Impact with Hood

• HIC Value of Case 3 is higher than Case 2 as we have used Aluminium as hood Material.Case 3 value of HIC15 was within safe standard HIC15 of EURO NCAP protocol.

CONCLUSION:

Three Different type of cases has been performed and the results are compared.There is avariation in the values for stress/strain and HIC15 for all the cases because of the different material properties.

GOOGLE DRIVE LINK : https://drive.google.com/file/d/1peMLScGAVPN94_nXlvyZ4KE86ljGZEjj/view?usp=sharing