Analysis of failure Mechanism of different material cards in Radioss under a thick plate using a rigid sphere

Analysis of failure Mechanism of different material cards in Radioss under a thick plate using a rigid sphere

Objectives: To simulate and perform using different failure models and compare the given cases in term of the material properties and their behaviour in the deformation

Procedure:

The following are the 7 cases that we have to simulate, by modifying some corrections in the material card as well as in the property card

Case-1: Run the model as it is . Name the model as law2_epsmax_failure

Case-2: in/Fail/JOHOSON, change ifail_sh=1,Dadv=1 and ixfem=1 Run the model as Law2_epsmax_crack.

Case-3: Delete/FAIL/JOHOSON CARD. Run the model as law2_epsmax_nofail.

Case-4: Delete the value of Eps_p_max and run the model with the name Law2

Case-5: convert this material model to law1 eleastic with same density,E,nu and run check the results

Case-6: open Law27_0000.rad and run the model with law27

Case-7 : Creating a material card with law36, and adding some details

CASE1: Run the model as it is . Name the model as law2_epsmax_failure

1. Import the crash beam file by using import solver desk
3. /MAT/LAW2 (PLAS_JOHNS)

This law represents an isotropic elasto-plastic material using the Johnson-Cook material model.

3. This model expresses material stress as a function of strain, strain rate and temperature. A built-in failure criterion based on the maximum plastic strain is available.
4. As per the objective we have to run the simulation without any modification in element properties card(default)
6. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
8. After running the file open the output file and check the energy error and mass error
10. Play the animation file as we seen in the graphical area the model simulate as per the given data
12. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
13. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-2: in/Fail/JOHOSON, change ifail_sh=1,Dadv=1 and ixfem=1 Run the model as Law2_epsmax_crack.

1. We have to change some parameters in/fail/Johnson such as per given
2. The reason behind changing the parameters is that we have to compare that how we behave at different parameters by changing same parameters
3. So go to failure Johnson and edit parameters
5. After editing the parameters run the model and save it in a respected folder.
6. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
8. After running the file open the output file and check the energy error and mass error
10. Play the animation file as we seen in the graphical area the model simulate as per the given data
12. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
13. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-3: Delete/FAIL/JOHOSON CARD. Run the model as law2_epsmax_nofail.

1. We have to delete the Johnson fail card.
2. The reason behind deleting the failure card is to absorb how to model simulate and how elements of model behave So go to failurecard of Johnson and delete it
4. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
5. After running the file open the output file and check the energy error and mass error
7. Play the animation file as we seen in the graphical area the model simulate
9. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
10. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-4: Delete the value of Eps_p_max and run the model with the name Law2

1. Here We have to delete the EPS_P_max
2. So go to the material properties and select the EPS_P_mas and keep it value as zero
4. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
6. After running the file open the output file and check the energy error and mass error
8. Play the animation file as we seen in the graphical area the model simulate
10. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
11. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-5: convert this material model to law1 eleastic with same density,E,nu and run check the results

1. In this case we have to convert the law2 material card to law1 material which know as elastic card it can be converted in material card
2. /MAT/LAW1 (ELAST)
3. This keyword defines an isotropic, linear elastic material using Hooke's law. This law represents a linear relationship between stress and strain. It is available for truss, beam (type 3 only), shell and solid elements.
5. After selecting the material give some input value such as , density= 0.0028 E=71000.0,nu=0.33
6. After changing the law2 material card to law1 material card run the model
8. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
9. After running the file open the output file and check the energy error and mass error
11. Play the animation file as we seen in the graphical area the model simulate
13. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
14. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-6: open Law27_0000.rad and run the model with law27

1. Import the crash beam file by using import solver desk
2. /MAT/LAW27 (PLAS_BRIT)
3. This law combines an isotropic elasto-plastic Johnson-Cook material model with an orthotropic brittle failure model. Material damage is accounted for prior to failure. Failure and damage occur only in tension. This law is applicable only for shells.
4. Change the shell properties to recommended shell properties
5. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
6. After running the file open the output file and check the energy error and mass error
8. Play the animation file as we seen in the graphical area the model simulate as per the given data
10. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
11. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-7 : Creating a material card with law36, and adding some details

1. In this case we have to convert the law2 material card to law36
2. /MAT/LAW36 (PLAS_TAB)
3. This law models an isotropic elasto-plastic material using user-defined functions for the work-hardening portion of the stress-strain curve (for example, stress vs. plastic strain) for different strain rates.
4. Change the material properties in law36 as specified
6. Create a stress- strain curve and apply it to the property
8. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
10. After running the file open the output file and check the energy error and mass error
12. Play the animation file as we seen in the graphical area the model simulate
14. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
15. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Result study:

Case N0	parameter	no. of cycles	Error (%)	Mass error (%)	Failure type	Property exhibited
1	Law2_epmax failure	49479	0.2	0	deletion	ductile
2	Law2_epmax crack	49396	4	0	crack	ductile
3	Law2_epmax nofail	49404	0.8	0	deletion	ductile
4	Law2_no epmax	49303	1.1	0	deletion	ductile
5	Law1	47968	0.3	0	none	elastic
6	Law27	49355	1.1	0	deletion	brittle
7	Law36	52130	1.5	0	Crack and rupture	ductile

• Law2_epmaxfailure: the EPS_p_max is set to 0.151. failure mode is set to Fail_JONHSON with ifail_sh=0,ixfem

The element fails when the stress and strain value reach 15.1% of plastic strain

Therefore the elements are deleted rapidly

• Law2_epmax­_crack: the EPS_p_max is set to 0.151. failure model is set to fail_JOHNSON with ifail_sh=1, Ixfem=1

Therefore the element are cracked and then deleted

• Law2_epmax_nofail: theEPS_p_max is set to 0.151.failure mode is not defined element are delected when they reach the plastic strain of 15.1%
• Law2_no_epmax: after delecting EPS_max value we can observe that the internal energy has increased a substantial amount and the plate is showing elastic behaviour

The value of von mises stress is also less as compared to previous cases

• Law1: the material model is changed to law1 elastic with same density and nu and E, this law define linear elastic relationships between stress and strain

The higher value of von Mises stress

Proves the elastic behaviour of the plate

• Law27: The element are deleted as soon as the tensile failure strain value reaches 15.1% of the maximum tensile strain
• Law36: the law model an isotropic elasto-plastic material using user-defined functions for the material using user–defined functions for the work Harding portions of the stress-strain curve for different strain rates

The value of the kinetic and internal energies is higher than law27

• Law2_epmaxfailure: the element get ruptured first and then get deleted as a whole No crack formulations take place
• Law2_epmax­_crack: the only difference here is the element crack before getting deleted
• Law2_epmax_nofail: the element gets delete post rupture
• Law2_no_epmax: the element rupture and then gets deleted
• Law1: slight tear can be observed on some of the elements but no element undergoes failures
• Law27:the element gets deleted at once without exhibiting any signs of rupture
• Law36:the element makes some plastic behaviour and ruptures while getting chipped away

Graph : total energy is identical for first 5 case following a uniform increase in energy, but for case 6, the energy lower a bit after starting and increases abruptly

For law36 the total energy is uniform at elastic state and when plate ruptures, the energy deflects

On filed scenario

The analysis of the 7 case gives slight knowledge on different types of mechanisms, associated with different material cards that causes failure of the plate

If the subject under study had been elastic, law 1 would have been the ideal choice

If the subject under study had been brittle material then, law 27 would have been the ideal choice

Law2_epmax_crack would represent the most ideal case on filed scenario with highest degree of accuracy

Conclusion

• The simulations for 7 cases are run as specified
• The .out files are compared
• The graphs are plotted for energies

link for assignment- https://1drv.ms/u/s!AlDYq9nTGAGChQ646Y4utuktJpwQ?e=3Fm9Km