Assignment 5-RADIOSS Interfaces & Study of Effect of Notches Challenge

OBJECITVE:

To mesh the given model and run the crush tube model in six different mentioned cases

Steps to mesh Bumper:-

• Bumper model is .hm file , so directly open the model in the software
• Look for any geometry error of the model, auto cleanup the same
• Mesh the model with quad elements of 6mm size, like shown below
  
• Remesh the area where mesh flow is not proper

Case 1 setup and procedure[run the model as it is]:-

• Import the solver deck file
• Run the radioss file, go to analysis>radioss>save the file in desired location>radioss
• Few animation files, time history files, output files will be created in the same location
• Open the output file and look for energy error and mass error
  
• We can see there is no mass error and energy error is -3.8% which is acceptable, so move on with further steps
• Open the animation file in Hyperview to see the displacement, contact forces and von mises
  Displacement
  
  Contact forces
  
  Von misess
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.22E+04 kg*mm2/ms2
  Resultant Normal force=1338 KN
  Resultant Tangent force=5.37KN

Case 2[Change Inacti =6]:-

• Open the rad file, go to contact interfaces change Inacti=6
  
• Inacti option is used if there is any initial penetration exist in the model
• In this case there is no initial penetration, so we can see the same result like above
• Run the radioss file, go to analysis>radioss>save the file in desired location>radioss
• Few animation files, time history files, output files will be created in the same location
• Open the output file and look for energy error and mass error
  
• We can see there is no mass error and energy error is -3.8% which is acceptable, so move on with further steps
• Open the animation file in Hyperview to see the displacement, contact forces and von mises
  Displacement
  
  Contact forces
  
  Von mises
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.22E+04 kg*mm2/ms2
  Resultant Normal force=1338 KN
  Resultant Tangent force=5.37KN

Case 3[Create Type 11 contact and run]:-

• Import the rad file into the software
• go to contact interfaces remove type 7, and create Type 11 contact
• In this case, we have to select master line and slave line
• Anyway the crash tube is hitting a rigid wall ,so we can select the components as both master as well as slave
• Use default type 11 properties
  
• Now repeating the same steps from above cases
  
  Energy error =-3.1%
• Displacement
  
  Contact forces
  
  Von mises
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.2796E+04 kg*mm2/ms2
  Resultant Normal force=1184.3 KN
  Resultant Tangent force=11.54KN

Case 4[Remove both notches and remove boundary condition and run]:-

• In this case remove notches by translate option and by align node option
• The notches are removed and it is shown in below image
  
• Now run the radioss file and repeat the same procedures
  
  Energy error=-3.2%
• Displacement
  
  Contact force
  
  Von mises
  
  
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.287E+04 kg*mm2/ms2
  Resultant Normal force=1397 KN
  Resultant Tangent force=28.78KN

Case 5[Create Nothces in middle and run the model]:-

• Create notches in the middle by using translate option
  
• Repeat the same procedure, output file is shown below
  
  Energy error=-3.1%
• Displacement
  
  Contact force
  
  Von mises
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.249E+04 kg*mm2/ms2
  Resultant Normal force=1373 KN
  Resultant Tangent force=16.87 KN

Case 6[Create notches by node on opposing 2 faces]:-

• Remove the notches from two faces from above case and run the model
  
• The output file after running the simulation is shown below
  
  Energy error=-3.2%
• Displacement
  
  Contact force
  
  Von mises
  
• Plot the graph for rigid walls , internal energy in hypergraph 2d
  
  Internal energy=4.232E+04 kg*mm2/ms2
  Resultant Normal force=1300.31 KN
  Resultant Tangent force=31.67 KN

Result and conclusion:

• 	Internal energy(kg*mm2/ms2)	Resultant Normal Force(KN)	Resultant Tangent Force(KN)	Contact force(KN)	Von mises
  Case 1	4.22 E+04	1388	5.37	93.75	0.694
  Case 2	4.22 E+04	1388	5.37	93.75	0.694
  Case 3	4.2796 E+04	1184.3	11.54	82.13	0.6341
  Case 4	4.2487 E+04	1397	28.78	66.28	0.7394
  Case 5	4.2493 E+04	1373.13	16.87	70.68	0.6467
  Case 6	4.2321 E+04	1300.13	31.67	97.03	0.6696

• Displacement of the elements is almost same for all the cases
• We can see there is no diffrence between case 1 and 2, becase there is no initial penetration or self intersection, so inacti option will not be effective
• We can see in case 4 where there is no notches , thers is a dip in contact force
• Without notches the defromation will be sudden and irregular
• We can see the contact force is high in case 6, where we have notches only on opposite faces
• Von mises yeild criterion is high in case 4