Week - 8 Mass Scaling
Week 8 Report
Aim: Use mass scaling to reduce the runtime of a model and ensure the stability of mass scaling. The hard limit on mass scaling is 8% and stability should be completely intact. Find best DT and TSSFAC. At last run the same model using implicit solver with necessary changes and compare implicit and explicit runtime.
Procedure:
Explicit Analysis:
case 1: Import model, TSSFAC is 0.9, DT2MS is -3.5e5
Run simulation, see result below
Change TSSFAC to 0.8
case 2: reduce DT2MS until mass percentage reaches 8%. Change DT2MS to -6e-5, TSSFAC 0.9, run simulation
TSSFAC=0.8
case 3: DT2MS to -8e-5, TSSFAC 0.9
TSSFAC 0.8
case 4: DT2MS to -1e-4, TSSFAC 0.9
TSSFAC 0.8
case 5: last case mass percentage is 6%, we keep changing DT2MS to -1.1e-4, TSSFAC 0.9
TSSFAC 0.8
In this case, both mass percentage increase is 20%, more than 8%. We reduce DT2MS
case 6: DT2MS to -1.05e-4, TSSFAC 0.9
TSSFAC 0.8
case 7: keep changing DT2MS to -1.02e-4, TSSFAC 0.9
TSSFAC 0.8
case 8: last case mass percentage increase is 7.47%, close to 8%, we change DT2MS to -1.024e-4, TSSFAC 0.9
TSSFAC 0.8
case 9:DT2MS -1.028e-4, TSSFAC 0.9
TSSFAC 0.8
case 10:DT2MS -1.029e-4, TSSFAC 0.9
TSSFAC 0.8
Now we got mass percentage increase around 8%.
Implicit Analysis:
We are going to add implicit keywords to run implicit analysis. See keywords below:
case 1: DT2MS -3.5e-5, TSSFAC 0.9
case 2: DT2MS -1.029e-4, TSSFAC 0.9
Conclusion:
1. We can see, compared with TSSFAC 0.8 and 0.9, mass increase does not change. So TSSFAC does not effect mass scaling.
2. With DT2MS -1.029e-4, TSSFAC 0.9 (0.8), mass percentage increase is around 8%, that is the optimized parameter.
3. With D2TMS increases, mass percentage increase increases. However, runtime decreases at the beginning and there is no pattern later (sometimes increases, sometimes decreases).
D2TMS VS runtime:
DT2MS vs mass incease %:
4. Normally TSSFAC is from 0.6 to 0.9, with TSSFAC increase, runtime decrease.
5. Implicit is much faster than explicit in this case(3 seconds), in implicit analysis, DT2MS and TSSFAC does not effect the runtime.