Assignment 4-RADIOSS Material Laws Challenge

#4 Assignment Crashworthiness Analysis using Hypermesh and Radioss

1. Objective:

• To apply the various cases as mentioned in the above question on the given failure johnson cook material.
• To plot the graphs(Post-processing) with respect to the obatined values from those cases.
• To compare the obtained results, from those cases.

2. Software used: Altair Hyperworks Desktop 2020.

3. User profile: Radioss

CASE-1 (Simulation without making changes)

• Import the Johnson Failure model 0000.Rad file into the Radioss user profile.

• You can see the as below  in the graphics area.

 

• View it in the "Shaded elements with mesh lines". 

 

• Check the card for the default values.

• Check the material card.
• 
• Check the property card.

• Click on the analysis from the panel area.
• Click on the Radioss and you will see this panel.
• Select the location where the files has to be saved.
• Click on the include connectors and "-nt 4.

 

 

Click on Radioss, then a pop up appears, wait for the process complete and  you can see the job completed as shown in the image.

 

 

• In the target location the files will be saved there you can see the .Out format file where the values are at end of the file, these are the values of internal energie,kinetic energy, etc.,

 

• The obtained last cycle values are:

Energy error = 0.8%

Internal energy = 0.2730E+05 KJ

Kinetic energy = 67.81 KJ

External work = 0.2721E+05 KJ

Mass error = 0

Elapsed time = 112.27 s

Total number of cycles = 49380

Next open the file with .Rad format file

 

• Check the TFreq and Run(Tstop) values.
•  Now open the Hyperview in the Hyperworks and insert the .H3d format file from the target location and click on apply
• Click on Cantour and switch the result type to Von Mises and click on apply.

• The simulation can be seen as shown.
• Here the material law is applied.
• The plate possess both the elastic and plastic nature

 

• Now switch to the Hypergraph 2D window.
• Graph has to be plotted for the rigid walls
• Insert the T01 file  saved in the location.

• Select as per the above image and click on apply and a pop-up appears as below.
• Change them as below image.

 

• Click on ok then the graph is plotted and appears on the graphical area.

Now plot the graph for the below parameters.

• Usually the internal energy energy starts from the origin, And it increases because of the increase in displacement.
• The kinetic energy will slightly vary at the time of element breakage.
• The total energy is the combination of all energies. So, it will increase as shown.
• The hourglass energy is constant through out the process. Because, the property card is assigned with the recommended
  values such as Ishell:24, Ismstr:2, Ish3n:2, Iplas:1, Ithick:1, N=5.

CASE-2 (Values changed in Failure Card):

The values in the material card is same and the values in the failure card has to be changed.

The values to be changed are Ifail_sh = 1, Dadv = 1, Ixfem = 1.

 

 

The Results are:

Energy error %= 4.1%

Internal Energy=0.3082E+05KJ

Kinetic Energy=61.40 KJ

External Energy=0.2980E+05

Mass error=0

Elapsed time=58.53s

No. of Cycles= 49217

 

Post-Processing:

Graph is plotted for the various parameters.

 

Rigid Wall Forces: Total Resultant force reaches peaks at thye time of impact.

 

 

Graph for Internal Energy: The internal energy starts from beginning and reaches peaks at the end.

Graph for Kinetic Energy: The variation in the kinetic energy starts from the beginning.

Graph for HourGlass Energy: The Hourglass energy is integrated and it will be constant due to assigning Ishell:24

Graph for Total Energy: The Total energy rises with increase in Internal & Kinetic Energy.

Graph for Contact Energy: The contact energy also remains same.

CASE-3 (Delete the Failure Johnson Card):

The File is imported and the failure card is deleted.

 

• Now run the simulation without changing parameters or values, open the 0001.Out file saved in the target loaction and observe the values as shown below.

The Result Values

Energy error = 0.8%

Internal energy = 0.2730E+05 KJ

Kinetic energy = 62.10 KJ

External work = 0.2736E+05 KJ

Mass error = 0

Elapsed time = 55.64 s

Total number of cycles = 49408

 

• The simulation is runned and by applying Von misses in the contour the impact the on the plate can be seen in the below animation.

 

Post-Processing:

Graphs are plotted by importing the T01 file to the hypergraph

 

Rigid Wall forces: Graph is plotted for rigid walls and the total resultant force.

Internal Energy:

The graph is plotted for internal energy, Internal energy increases and is similar to previous cases.

Kinetic Energy: The kinetic energy is less and plotted as below.

Hourglass Energy: The Hourglass energy is constant.

Total Energy: Total energy increases with increase in internal energy and kinetic energy

CASE-4 (Delete the eps max value from the material card):

 The eps max value is reset to 0.

The simulation is runned with name it as Law 2.

 

 

 

 

The Result Values

Energy error = 1.1%

Internal energy = 0.3879E+05 KJ

Kinetic energy = 3.018 KJ

External work = 0.3838E+05 KJ

Mass error = 0

Elapsed time = 55.19 s

Total number of cycles = 49304

Post-Processing: The graphs has to be plotted for various parameters to observe the deformation of plate.

Total Resultant Force: The graph rises from the beginning.

 

 

Internal Energy: The Internal energy gradually increases to the top.

Kinetic Energy: The Kinetic energy goes on in a Zig-Zag manner all over the cycle.

Hourglass Energy: The energy will be constant throughout the cycle.

Total Energy: The total energy is same as the kinetic energy.

 

CASE-5 (Changing the material law to M-1 Law):

In the material card the law is changed to M-1 Elast.

 

Then the simulation is runned and the values has to be noticed.

 

The Result Values

Energy error = 1.3%

Internal energy = 0.8632E+06 KJ

Kinetic energy = 3337. KJ

External work = 0.8568E+06 KJ

Mass error = 0

Elapsed time = 110.96 s

Total number of cycles = 47969

Applying the Von Misses in Contour Displacement, the deformation can be observed as below in the Hyperview window.

 

 

Post-Processing: The graphs has to be plotted for various parameters to observe the deformation.

Total Resultant Force: The total resultant force gradually.

 

 

Internal Energy: The Internal energy also gradually increased.

Kinetic Energy: Initially its is low and it goes zig-zag with a rise at the end of the simulation.

Hourglass Energy: It will be constant throughtout the simulation.

Total Energy: It will be gradually rising.

CASE-6 ( Changing the Material card to Law 36):

The material card is changed to Law 36 also the values will be modified as below,

 

The factor id is set to new curve which is created from the collector, with the respective values in the image.

The simulation is runned and the values are noticed.

 

 

 

The Result Values:

Energy error = -18.4%

Internal energy = 0.3501E+05 KJ

Kinetic energy = 900.1KJ

External work = 0.4407E+05 KJ

Mass error = 0

Elapsed time = 53.53 s

Total number of cycles = 47719

Post-Processing:

The results has been plotted with various parameters,

Total Resultant Force: The total resultant force is as shown in the graph.

Internal Energy: The Internal energy increases with time.

Kinetic Energy: The graph is zig zag showing the kinetic energy.

Hourglass Energy: The energy goes increasing constantly

Total Energy: The Total energy  increases gradually.

 

CASE-7 (Changing the Material Card to Law-27): 

 

The simulation is runned with above mentioned parameters,

The Results are:

Energy Error%= 0.6%

Internal Energy=0.2929E+05KJ

Kinetic energy=43.24KJ

External Energy=0.2917E+05KJ

Mass error=0

No.of cycles=49486

Time Elapsed=59.68s

Post Processing:

The results are plotted as graphs with various parameters.

Total Resultant Force: The resultant force rises.

Internal Energy: It increases constantly from the beginning.

Kinetic Energy: It will be low at beginning and increases at the end.

Hourglass Energy: It will be constant throughout the cycle.

Total Energy: It will increase gradually.

 

 

Comparison of 7 Cases:

Basis of Comparison	Case-1	Case-2	Case-3	Case-4	Case-5	Case-6	Case-7
Energy Error (%)	0.8%	4.1%	0.8%	1.1%	1.3%	-18.4%	0.6%
Internal Energy	0.2730E+05KJ	0.3082E+05KJ	0.2730E+05KJ	0.3879E05KJ	0.8632E+06KJ	0.3501E+05KJ	0.2929E+05KJ
Kinetic Energy	67.81KJ	61.40KJ	62.10KJ	3.018KJ	3337KJ	900.1KJ	43.24KJ
External work	0.2721E+05KJ	0.2980E+05KJ	0.2736E+05KJ	0.3838E+05KJ	0.8568E+06KJ	0.4407E+05KJ	0.2917E+05KJ
Mass Error	0	0	0	0	0	0	0
Elapsed time	112.27s	58.53s	55.64	55.19s	110.96s	53.53s	59.68s
No. of Cycles	49380	49217	49408	49304	47969	47719	49486
Material Law used	Law to with values	Law 2 Changing the value in the failure card	Law 2 by deleting failure card	Law 2 by removing the plast strain epsmax	Law 1	Law 36	Law 27

 

Conclusion:

• Applied the various cases as mentioned in the above question on the given failure johnson cook material.
• Plotted the graphs(Post-processing) with respect to the obatined values from those cases.
• Finally, compared the obtained results from those cases.