Challenge

Assignment 4-RADIOSS Material Laws Challenge

OBJECTIVE:

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:

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

Ship work like this
in your own course.