Week - 8 Mass Scaling
AIM: To use the MASS-SCALING to reduce the runtime of the simulation using EXPLICIT and IMPLICIT solver.
PROCEDURE:
- A model for mas-scaling is provided. In this we have to chang the mass-scaling so that it reaches to limit of *% of mass scaling.
- The model is shown below:
EXPLICIT:
WITHOUT MASS-SCALING
- Here the Termination is 600ms.
- Now we will run .k file
- Here you can see that the the Termination time is shown as 67 hrs..
WITH MASS SCALING
- Now to mass-scaling is done by TIMESTEP keyword.
- For that go tho the MODEL>KEYWRD>CONTROL>TIMESTEP
1.
- Initially the value of DT2MS is -3.500e-05 and TSSFAC is 0.9.
- Now DT2MS is used to reduce the Timestep of the simulation also its helps to add or reduce the mass.
- When DT2MS is Postive then the mass is added and when DT2MS is negative then the mass is reduced.
- And TSSFAC (time step safety factor)
- Now we will run the .k for the simulation.
- Here the we can see that that the estimated time decreases as the TIMESTEP = 42hrs
- The added mass= 0.00e+00
- The %increases=0.00e+00
2.
- Now we will change the TS2MS=-5.50e-05
- Simulation:
- EST. TIME: 31 hrs 13 min
- ADDED MASS: 2.85e+03
- % increase : 1.00e-02
- Here you can clearly see that all the Three values are increasing. Now we have to change the TS2MS until we get the % increase= 8%
3.
- TS2MS=-8.50e-05
- Simulation:
- EST. TIME: 18 hrs 13 min
- ADDED MASS: 4.51e+05
- % increase : 1.58e+00
- Here the value of percentage is now positive
4.
- TS2MS=-9.50e-05
- SIMULATION:
- EST. TIME: 26 hrs 24 min
- ADDED MASS: 1.227e+06
- % increase : 4.313e+00
5.
- TS2MS=-10.00e-05
- SIMULATION:
- EST. TIME: 23 hrs 13 min
- ADDED MASS: 1.827e+06
- % increase : 6.423e+00
6.
- TS2MS=-10.010e-05
- SIMULATION:
- EST. TIME: 23hrs 32 mins
- ADDED MASS: 2.295e+06
- % increase :8.06e+00
- So here we got the 8% increment at TS2MS=-10.01e-05
- Now the we will compare the comutational time with the help of HISTOGRAM
| SR no | DT2MS | % Increase | EST TIME (Hrs) | EST TIME(s) |
| 1 | -3.50e-05 | 0.00 | 42 | 151200 |
| 2 | -5.50e-05 | 0.01 | 31.13 | 112068 |
| 3 | -8.50e-05 | 1.58 | 18.23 | 65628 |
| 4 | -9.50e-05 | 4.3 | 26.24 | 94464 |
| 5 | -10.00e-05 | 6.42 | 23.13 | 83268 |
| 6 | -10.01e-05 | 8.06 | 23.32 | 83952 |
HISTOGRAM
- The computational time given is a tentative it might vary.
- Now we will keep the DT2MS=-1.01e-04 and will change the TSSFAC=0.8 and 0.7
1. TSSFAC=0.8 and DT2MS=-1.03e-04
- EST. TIME: 18hrs 12 mins
- ADDED MASS: 2.295e+06
- % increase :8.06e+00
2. TSSFAC=0.7 and DT2MS=-1.03e-04
- EST. TIME: 24hrs 47 mins
- ADDED MASS: 2.295e+06
- % increase :8.06e+00
IMPLICIT:
- Now for the Implicit function we need Implicit Card.
- First we will go to *CONTROL_IMPLICIT_AUTO
- Now to activate the Implicit function we need to set the IFLAG=1 for that go to *CONTROL_IMPLICIT_GENERAL
- Now next is *CONTROL_IMPLICIT_SOLUTION
- For implicit calculation we will use *CONTROL_IMPLICIT_SOLVER
- The run time is same as the EXPLICIT solver.
- Now we will run the simulation at TS2MS=-3.50e-05
SIMULATION:
- Now as we see here the time required to complete the simulation in EXPLICIT is 42 hrs
- Where as same problem is solve in the IMPLICIT is 8 mins 36 sec.
OUTCOMES:
- Got knowledge about the DT2MS and TSSFAC.
RESULTS
- The objective is achieve by changing the values of DT2MS and TSSFAC
- The HISTOGRAM is plotted for the EXPLICIT solver.
- Same example is solved by the Implicit solver and the the comaparison between the RUNTIME is also done.