Week - 8 Mass Scaling
WEEK 8 CHALLENGE - MASS SCALING
AIM:
To compare the run time using Explicit and Implicit mass scaling to reduce the run time of a model and the hard limit on mass scaling is 8% and stability should be completely intact using Ls-Dyna.
GIVEN MODEL:
PROCEDURE:
CASE 1:
MASS SCALING IN EXPLICIT METHOD
Import the given .k file
Iteration 1: DT2MS is given as -3.500e-05 and TSSFAC as 0.9 in Control_Timestep.
Run the Simulation in LS Run.
The Estimated Time is 96593 Sec (i.e. 26hrs 49mins).There is no mass added because the DT2MS< 0. We are going to Reduce the Run time by increasing the Dt2MS value.
Iteration 2: DT2MS is given as -6.500e-05 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 88578 Sec (i.e. 24hrs 36mins).The Percentage of mass added is 0.057%. Our hard limit on Mass scaling is 8% so we can increase the DT2MS value.
Iteration 3: DT2MS is given as -9.500e-05 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 63157 Sec (i.e. 17hrs 32mins).The Percentage of mass added is 4.31%
Iteration 4: DT2MS is given as -1.000e-04 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 73939 Sec (i.e. 20hrs 32mins).The Percentage of mass added is 6.42%
Iteration 5: DT2MS is given as -1.010e-04 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 75607 Sec (i.e. 21hrs 0mins).The Percentage of mass added is 6.92%
Iteration 6: DT2MS is given as -1.020e-04 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 102198 Sec (i.e. 28hrs 23mins).The Percentage of mass added is 7.47%
Iteration 7: DT2MS is given as -1.028e-04 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 64261 Sec (i.e. 17hrs 51mins).The Percentage of mass added is 7.94%
Iteration 8: DT2MS is given as -1.029e-04 and TSSFAC as 0.9 in Control_Timestep.After Running the Simulation.
The Estimated Time is 92469 Sec (i.e. 25hrs 41mins).The Percentage of mass added is 8.00%
While increasing DT2MS value we are getting various Estimated Time and we reached our hard limit 8% at DT2MS -1.029e-04.
| DT2MS | RUN TIME (SEC) | % OF MASS SCALING | TSSFAC |
| -0.0000350 | 96593 | 0.00 | 0.9 |
| -0.0000650 | 88578 | 5.78 | 0.9 |
| -0.0000950 | 63157 | 4.31 | 0.9 |
| -0.0001000 | 73939 | 6.42 | 0.9 |
| -0.0001010 | 75607 | 6.92 | 0.9 |
| -0.0001020 | 102198 | 7.47 | 0.9 |
| -0.0001028 | 64261 | 7.94 | 0.9 |
| -0.0001029 | 92469 | 8.00 | 0.9 |
We are going to Plot the histogram by comparing the runtime with mass scaling trials.
Now we are going check the Estimated time and mass scaling percentage by changing TSSFAC.
- TSSFAC as 0.8 and DT2MS as -1.029e-04
After Running the Simulation.
The Estimated Time is 89451 Sec (i.e. 24hrs 50mins).The Percentage of mass added is 8.00%
- TSSFAC as 0.7 and DT2MS as -1.029e-04 in Control_Timestep.After Running the Simulation
The Estimated Time is 83298 Sec (i.e. 23hrs 8mins).The Percentage of mass added is 8.00%
We have seen a difference in Estimated Time while Decreasing TSSFAC value but the Mass Scaling Percentage is Same.
| DT2MS | RUN TIME (SEC) | % OF MASS SCALING | TSSFAC |
| -0.0001029 | 92469 | 8.00 | 0.9 |
| -0.0001029 | 89451 | 8.00 | 0.8 |
| -0.0001029 | 83298 | 8.00 | 0.7 |
CASE 2:
MASS SCALING IN IMPLICIT METHOD
Create Implicit Card in the Control as shown below
IMPLICIT AUTO
IMPLICIT GENERAL
IMPLICIT SOLUTION
IMPLICIT SOLVER
After creating Implicit control card we will check by changing Control Timestep as like Explicit method.
- DT2MS as -3.500e-05 and TSSFAC as 0.9 in Control_Timestep and save the file..After Running the Simulation
The run time required to complete the simulation for DT2MS as -3.500e-05 is 2mins 26sec.the percentage increase in mass is not reported.
- DT2MS as -1.029e-04 and TSSFAC as 0.9 in Control_Timestep and save the file..After Running the Simulation
The run time required to complete the simulation for DT2MS as -1.029e-04 is 2mins 24sec.the percentage increase in mass is not reported, as the time step is larger than Explicit method.
CONCLUSION:
We have compared the run time by increasing and decreasing DT2MS and TSSFAC value and plotted the runtime with mass scaling trials and also run the same model using implicit solver with necessary changes and compared implicit and explicit runtime.
Google drive file link: https://drive.google.com/file/d/1VuE7Bw3xogzu0xXT2gULTt8Dk0p0sO_T/view?usp=sharing