Assignment-4
Assignment – 4
Compare 7 cases as discussed in last 3 slides, in a tabulated format on the basis of:
https://drive.google.com/drive/u/1/folders/1fb5EgMgQxeAcW4FmyJTcIKqGz4_Vju2Z
Comparison of several cases with Law 2, Johnson cook material law, with
- Failure model
- Crack propagating
- No failure
- With EPS_f =0, and Johnson cook
- Same elastic condition in Law 1.
Put all recommendation data in model and visualize the results for Energy and time step comparison,
UNIT SYSTEMS DEFINITION
-----------------------
MASS LENGTH TIME
WORK UNIT SYSTEM . . . . . ( g , mm , ms ) 1.0000000000000E-03 1.0000000000000E-03 1.0000000000000E-03
INPUT UNIT SYSTEM . . . . . ( g , mm , ms ) 1.0000000000000E-03 1.0000000000000E-03 1.0000000000000E-03
Case 1: Law 2 Johnson cook material law with failure model
- Law 2 Elasto-plastic with given properties:
- E = 71000
- Nu = 0.33
- Density = 0.0028
JOHNSON COOK MODEL:
- YIELD COEFFICIENT A . . . . . . . . . .= 0000000000
- YIELD COEFFICIENT B . . . . . . . . . .= 3000000000
- YIELD COEFFICIENT N . . . . . . . . . .= 0.6300000000000
- EPS-MAX . . . . . . . . . . . . . . . .= 0.1510000000000
- SIG-MAX . . . . . . . . . . . . . . . .= 0000000000
The above given properties gives results as in given image and in attached model file, can be visualize in Hyper view.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 1.39E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1018 E-3, and
Total Simulation time = 108.36 s.
Energy error are not more than 1% Max
Mass error = 0.0000
Total no. of cycles = 49480.
Case 2: Law 2 Johnson cook with crack propagation:-
Continue with the above mentioned same properties and some changes in failure model,
- Ixfem = 1
- Dadv = 1
- Ifail_sh = 1
Results visualize with cracking of elements before deleted from system.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 1.36E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1018 E-3, and
Total Simulation time = 75.50 s.
Energy error are not more than 1.1 % Max
Mass error = 0.0000
Total no. of cycles = 49480.
Case 3: Law 2 Johnson cook law with no fail model.
First of all, delete the fail model from system and check all other properties as recommended as per law and given data. And running the model with name “Law2_epsmax_nofail”.
The results are as follows.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 1.410E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1018 E-3, and
Total Simulation time = 78.35 s.
Energy error are not more than 1.2 % Max
Mass error = 0.0000
Total no. of cycles = 49405. (No of cycles are less 75 than first two cases)
Case 4: Law 2 with EPS_f_max = 0, with name Law 2.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 5.847E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1018 E-3, and
Total Simulation time = 79.66 s.
Energy error are not more than 1.2 % Max
Mass error = 0.0000
Total no. of cycles = 49304.
Case 5: Convert this law 2 Johnson cook with same properties of E, nu and Rho.
- E = 71000
- Nu = 0.33
- Rho = 0.0028
- With units system as stated above N
N mm ms g
I found the material id full elastic and not breakable and no element deleted from system.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 2.010E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1018 E-3 to 1.1100 E-3, and
Total Simulation time = 75.57 s.
Energy error are not more than 4.0 % Max
Mass error = 0.0000
Total no. of cycles = 47969.
Case 6: Law 27 with brittle/ MAT/PLAS_BRIT/
With the recommended properties assigned.
We can easily see in contour plot, Strain (VonMises, Max) with Simple Averaging is 1.623E-01, and within limits. And failure of the model also can be seen.
No Hourglass energy observed, total energy graph also smooth increase.
Time step = 1.1265 E-3 to 0.1105 E-3 and
Total Simulation time = 66.01 s.
Energy error are not more than 4.5 % Max
Mass error = 0.0000
Total no. of cycles = 41855.
Conclusion:
In conclusion, we compare the following things,
As from excel graph,
- No of cycles from case 1 to case 4 nearly same but case 4 to case 6 decreases suddenly.
- Simulation time is more in case one with failure model, and nearly same in all other models.
- Strain (VonMises) are approx. same in first three cases, and suddenly increase in case 4 and again decrease in case 5 to 6.
- Time step is nearly equal in first four cases then increases in case 5 and case 6.
- Energy error in first 4 cases in nearly 1% but in case 5 4 % and in case 6 its 4.5%.
So, With Law 27, PLAS_BRIT time step and energy error increases but other things decreases.
And With Johnson cook and failure model, Simulation time is much more than all other situation in same model without failure model. And without the EPS_f_max, strain (VonMises) increases.
https://drive.google.com/drive/u/1/folders/1fb5EgMgQxeAcW4FmyJTcIKqGz4_Vju2Z