Analysis of failure behaviour of a plate with  different materials (LAW1, LAW2, LAW27, LAW36 and Johnson-cook material ) using hypermesh Radioss.

Objective:

Analysis of failure behaviour of a plate with different materials (LAW1, LAW2, LAW27, LAW36 and Johnson-cook material ) using hypermesh Radioss.

Case 1

• Comparison of results with law 2, failure mode and law 27
• Open FAILURE_JOHNSON_0000.rad file
• Notice the properties change those to recommended if needed
• Run the model as it is and save it as LAW2_Epsmax_Failure

Case 2

• in /FAIL/JOHNSON, change ifail_sh=1, Dadv=1, ixtem=1
• run the model save it as Law2_epsmax_crack

Case 3

• Delete /FAIL/JOHNSON card
• Run the model and save the model it as law2_epsmax_nofail

Case 4

• Delete the value of EPS_p_max and run the model with name law2

Case 5

• Convert this material model to Law 1 elastic with same density, E, Nu run it

Case 6

• Open rad file
• Change the property to recommended
• Run the simulation and save it with Law27

Case 7

• For Law36 use two different curves one is standard curve and another one is test curve with given data

Procedure:

Case 1 :

• Import FAILURE_JOHNSON.0000.rad file into hypermesh
• Check for the recommended property change if needed
• Run the simulation by going to > Analysis > Radioss > save file as LAW2_Epsmax_Failure
• Open .h3d file in hyperview and play the animation

• as we can observe that elements are elements are getting deleted as the maximum plastic starin is reached

Energy error and mass error

• energy error and mass error are within the limits as expected because shell element properties are applied to it which recommended (similar for all cases)

Energy Plots

• by observing the graphs the internal energy is maximum where elements are getting deleted
• and total resultant force is goes on decreasing as elements get deleted

Case 2:

• in /FAIL/JOHNSON, change ifail_sh=1, Dadv=1, ixtem=1
• run the model save it as Law2_epsmax_crack
• open .h3d file in hyperview to viw the animation

• using this criteria we can see crack is being devoleped much more than case 1
• energy error and mass error are noted

• plot the graphs

• we can see in graphs that internal energy is getting contant for some grater time compared to case 1
• and resultant force is decreasing garadually when the crack is being devoleped

Case 3:

• Delete /FAIL/JOHNSON card
• Run the model and save the model it as law2_epsmax_nofail
• open .h3d file in hyperview to viw the animation

• same material but failure card is deleted
• eps_p_max value failure criteria is considered elements are deleted after (15.1% true plastic strain value)
• from the animation we can observe that elements are getting deleted when it reaches to eps_p_max value
• note down the energy error and mass error

• plot the respective graphs

• total resultanat force is decreasing in stepped manner
• and internal energy is similar as case 2

Case 4:

• Delete the value of EPS_p_max and run the model with name law2
• open .h3d file in hyperview to view the animation

• we can notice that after deleting EPS_p_max value elements are not getting deleted
• and von Mises stress comapratively higher
• note down the energy error and mass error

• plot the respective graphs

• we can see that there is no brake down in the graph
• the internal energy goes on increasing and total resultant force also increasing but none of the elements is getting deleted

Case 5:

• Convert this material model to Law 1 elastic with same density, E, Nu run it
• isotropic linear elastic material using hooks law. this law represents a linear relationship between stress and strain
• open .h3d file in hyperview to view the animation

• elements are not getting deleted
• von mises stress is higher than in other cases
• note down the energy error and mass error

• plot the respective graphs

• both graphs are in linear realtionship with each other
• and there is no breakdown point

Case 6

• Change the property to recommended
• Run the simulation and save it with Law27
• open .h3d file in hyperview to view the animation

• elements are deleted when it reaches to maximum tensile strain
• note down the energy error and mass error

• plot the respective graphs

• internal energy reaches to maximum and it breaks down again it goes on increases

Case 7 (Satandard Curve)

• For Law36 use two different curves one is standard curve and another one is test curve with given data
• open .h3d file in hyperview to view the animation

• elements get deleted from the center position completely
• note down the energy error and mass error

• plot the respective graphs

Case 7 (Test Curve)

• open .h3d file in hyperview to view the animation

• Energy error and mass error

• Plots the graphs

• Internal energy and resultant force increases realtively earliear compared to all other cases

Conclusion and results:

SL.no	total no of cycles	Energy error	Mass error	simulation time
CASE 1	49380	0.8%	0	215.94 s
CASE 2	49217	4.1%	0	210.79 s
CASE 3	49408	0.8%	0	222.15 s
CASE 4	48737	3.0%	0	208.77 s
CASE 5	47969	1.3%	0	209.02 s
CASE 6	49508	0.8%	0	206.48 s
CASE 7	52189	-1.1%	0	249.32 s

• Hourglass energy remained almost zero in every case
• due to the recommended property mass error and energy error remained within the limits