Assignment 4-RADIOSS Material Laws Challenge

OBJECTIVE:

• To run the Radioss engine file and compare the result between all the 7 cases

Case Setup:

 Case 1 (LAW2_epsmax_failure) 

• In this case let us import the Failure_johnson_0000.rad file
• In first case without aking any change to the model , run the file in Analysis>radiosss>save it in desired directory
• The material property is shown in below image
  
• After running the file, open the output file from the saved location
  
  Total run time=116.66 seconds
  Total number of cycles=49380
  Energy error=0.8%
  Mass error=0
• The energy error can be accepeted because it is less than 15%, now we can proceed with further steps
• Look at the displacement and von mises stress generated in the model, by going to Hyperview window
  Displacement
  
  Max displacement=1.586E+01 node 3984
  Von mises:
  
  Max=2.752E+02 node 3812
  Velocity:
  
  Max=2.389E+01 node 3994
  Percentage of thickness reduction
  
  Plastic strain along thickness:
  
  
  
• Now we should plot the graph for Time v/s Energies, for that go to hyper graph2d window
  
  Internal energy => Max=2.7E+04; min=0;
  Kinetic energy=>Max=179.25; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=2.7E+04; Min=0.004367;

Case 2 (LAW2_epsmax_crack) 

• In this case the we should change some values in failure card like shown in below image
  
  
  
• Run the file like done in previous case, open the output file for this case
  
  Simulation time=69.75sec
  Total number of cycles=49217
  Energy Error=4.1%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
  Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=3.08E+04; min=0;
  Kinetic energy=>Max=210.28; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=3.08E+04; Min=0.004367;

Case 3(Law2_epsmax_nofail)

• Open the previous case file, now delete the failure johnson card
• Run the file like previous case, save the model in desired location
• Open the output file from the location you have saved,
  
• Simulation time=56.04sec
  Total number of cycles=49408
  Energy Error=0.8%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
  Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=2.74E+04; min=0;
  Kinetic energy=>Max=332.072; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=2.74E+04; Min=0.004367;

Case 4(Law_2)

• In this case delete eps_max value and run the file
• Open the respective output file , we can find the mass error,number of cycles and time taken
  
• Simulation time=56.37sec
  Total number of cycles=48737
  Energy Error=3%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
  Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=6.4E+04; min=0;
  Kinetic energy=>Max=3.77; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=6.4E+04; Min=0.004367;

Case 5(Law_1)

• In this case open the previous case file, change the material card to Law1, like shown in below image
  
• Run the file with above material card 
• Open the output file to find out mass error
   
• Simulation time=51.20sec
  Total number of cycles=47699
  Energy Error=1.3%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
  Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=8.625E+05; min=0;
  Kinetic energy=>Max=3245.7; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=8.625E+05; Min=0.004367;

Case 6(Law_27)

• In this file open the law_27_0000.rad file
• Change the material card to Law_27 like shown below
  
• Edit the Shell property to the recomended shell properties like in previous assignment
  
• Now run the file like previous cases, and open the output file 
  
• Simulation time=54.36sec
  Total number of cycles=49508
  Energy Error=0.8%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
  Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=2.9E+04; min=0;
  Kinetic energy=>Max=425.88; min=0.004367;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=2.95E+04; Min=0.004367;

Case 7(Law_36)

• In this case we will be using law 36 material card, use the same properties as shown in slide
  
• In this case we should create a new function card with the given x and y values from slide
  
• After creating the test curve , run the radioss file in desired location and repeat the steps from previous cases
• After completing the simulation, open output file we can get to know the results like mentioned below
  
• Simulation time=60.48sec
  Total number of cycles=53157
  Energy Error=0.9%
  Mass Error=0
• Now the energy error generated in this case is acceptable, we can proceed with next step
• Open hyperview to see all the 5 animation
• Displacement
  
  Vonmises
  
  Velocity
  
  Percentage of thickness reduction
  
  Plastic strain along thickness
  
  
• Now plot the graph for Time v/s energies in hypergraph2d
  
  Internal energy => Max=9.6946E+04; min=0;
  Kinetic energy=>Max=178.42; min=0.004211;
  Hourglass=0(formation of hourglass energy is avoided)
  Total energy=> Max=9.6976E+04; Min=0.004211;
  
  

CONCLUSION:

• 	Displacement	Von mises	Internal Energy
  Case 1	1.58E+01	2.752E+02	2.7E+04
  Case 2	1.1277E+01	2.57E+02	3.08E+04
  Case 3	1.932E+01	3.1E+02	2.74E+04
  Case 4	5.011E+0	4.205E+02	6.4E+04
  Case 5	4.99E+0	1.102E+04	8.625E+05
  Case 6	1.699E+01	2.875E+02	2.9E+04
  Case 7	5.34E+00	1.226E+03	9.6946E+04

• From the above tabulated result, we can see the von mises stress is high in case4, in that case there is no eps_max value,
• since the value is deleted, we can observe the animation there is no crack generated in the model, that causes more amount of stress in the body without crack
• It is important to mention the Eps_max value , so case 4 will not be suitable for real life case.
• We can see there is no hourglass energy is formed because the recomended shell properties are used, like previous assignment
• By the process we come to know that , even if the materials are same, one single parameter can make big diffrence
• It is important to know the suitable properties for each cases