Assignment 6-Frontal Crash Simulation Challenge

OBJECTIVE:

• Objective of this project is to set the model for frontal car crash with mentioned time step
• Create rigid wall with specfied friction
• Create appropriate Interface, cross section for required output
• Balance the required mass and balance the COG to desired location

Steps Carried out:

 Import the rad file

• Import the 000.rad file into the software by import solver deck option
  
• Before starting with the process,keep in mind about the unit system 
• Let it be same in both hypermesh and hypercrash, open the .rad file in notepad to see the unit system used in the model
  
• The above image show the unit system used here is Kg,mm,ms
  the same will be used further

Create Rigid wall

• Create rigid wall by goint to Solver>right click create>RWALL>Plane
   
• Select the required node, Normal node and give the friction value as 0.1
  
• The rigid wall will be created like shown in below image
  

Create Appropriate interface

• Create the appropriate contact in the groups
• Go to Solver>Inter>Type 7>create interface with suitable parameters
• Give the friction value 0.2 as mentioned
• Below image shows the Type 7 intrface card
   

Check for penetration and intersection

• go to tool>penetration check>selct the group >check
  
• The above image tells us there is no collisions found in the group

Initial Velocity

• Now we have to create initial velocity card of 35mph
• we should covert m/h to mm/ms, by this we will get velocity value as 15.6464
• Go to solver>INIVEL>set the properties>select all the nodes
  

Add mass to balance the COG

• Check the weight of the model and the cog point
• compare it with the full model and adjust the cog point by adding the few masses to get the desired weight
• Now the weight of the model is 188kg, desired weight is 700 kg
• add some weight on the both seat frames to get the cog to required location
• in hypercrash go to mass>balancing , there we can see the weight of the model and cog
  
  
• Add mass in hypercrash by Load case>added mass>create new mass with type=1
  
• After adding the mass cog and total weight will be changed
  
  

Model checker

• Go to hypercrash>quality>model checker>run
• look for any errors and fix the same 
  
  there is no error in this model so we can move further

Set the frquency and run time

go to solver>run>ENG_run> set the tstop as 80ms

OUTPUT Request:

Sectional force

• We have to create sections in mentioned area, before creating section we have to create frame
• go to solver>frame>mov>create frame in required nodes using N1,N2,N3
  
  
  above image shows the frame is created 
• Create section card by solver>right click sect> create section by selecting frame id created in prev step
  
• Select the elements in gr shell id; delta=o.1(it cannot be zero); iframe=12; alpha=1.94;
  
  
  
  
• Create same type of sections with frame, wherever is required
  

Create Accelometer for B pillar

• Create accelometer for rocker component under B pillar
• go to Solver>right click>ACCEL>selct the nodes from rocker
  
• Acceleometer will be created lik shown below
  

 

INTRUSION FOR NODE 6695 AND 66244

• go to solver>TH>Node>create intrusion in above mentioned nodes
  

Create Output Blocks:

• So far we have setup the model, created sections and created accelometer
• Now we have to take the results from the same by creating output blocks
• go to model>output blocks>create new blocks for cross sections and accelometer
  
• Entity ID should be crossection and accelometer for respective types

RESULTS and DISCUSSION:

• Run the model and look for energy error 
  
• The energy error is less than 15%, so it is acceptable , now we can carry on with further steps
• The total ellapsed time is shown below
  
• Go to Hyperview open the .h3d file , look for displacement and von misess
  Displacement
  
  Max displacement=1.252E+03
  
  Vonmises
  
  Max von mises= 3.634E-01
• Go to Hyper graph2d for plotting the energies
• Sectional force in rail left and right
  
  Total resultant force of Rail left=3.190323
  Total resultant force of Rail Right=3.190323
  
  
• Sectional force in shortgun left and right
  
  Total resultant force of Shortgun left=7.396165
  Total resultant force of Shortgun Right=6.742527
  
  
• Sectional force in  A pillar Left and right
  
  Total resultant force of A pillar left=6.041878
  Total resultant force of A pillar Right=3.256452
  
  
• Axial Force recieved on rails of bumpers left and right
  
  Total resultant force of Rail of Bumpers left=5.260850
  Total resultant force of Rail of Bumpers right=6.740247
  
  
• Accelaration recieved at base of B pillar[ at rocker component]
  
  Accelaration on left side=8.259418 mm/ms2
  Accelaration on Right side=2.102724 mm/ms2
  
  
• Intrusion on dash wall
  
  Intrusion at node 66244= 923.37mm @79.5ms
  Intrusion at node 66695= 942.3997mm @79.5ms
• Energy Plots
  
  Kinetic energy
  max=8573.203 kg*mm2/ms2
  min=45969.722 kg*mm2/ms2
  
  Internal Energy max=37352.03 kg*mm2/ms2
  Contact Energy max=1198.01 kg*mm2/ms2

COCLUSION:

• The given model is set up for frontal crash with required interface, without any penetrations and intersection
• Created section in required positin for desired results
• Created Initial velocity card and applied to all the nodes
• Created all the required output blocks to plot the results