Week - 8 Mass Scaling

 AIM:

     To compare the run time using explict and implicit mass scaling to reduce the run time of a model and ensure the stability of mass scaling.

PROCEDURE:

Case-1:(Mass scaling for Explicit Method)
1.Import the keyword file.

2.The given model is meshed with solid elements.

3.Termination time is given as 600ms.

4.In control time step card DT2MS is -3.500E-0.5 and run the simulation with a scale factor is 0.9.

1.With time step -3.500E-0.5:

1.Scale factor is used as a factor of saftey because the DT2MS value is multiplied by TSSFAC and the result is the minimum value that the solver will accept as the saftey values.

Terimnation time:

2.The estimated time it is 121360 seconds which means 34 hours(approx). It has taken more simualtion time.

3.There is no added mass and percentage increases because it is 0.

4.It is possible to increase the DT2MS value until the mass percentage reaches 8%.

2.With time step -6.500E-0.5:

1.Change the DT2MS value -3.500e-0.5 to -6.500e-0.5 in control time step.

Termination time:

2.The percentage of mass added is 0.578% we cannot get the required percentage so increase the DT2MS value.

3.With time step -9.500E-0.5:

1.Change the DT2MS value -6.500e-0.5 to -9.500e-0.5 in control time step.

Termination time:

2.The percentage of mass added is 4.3% we cannot get the required percentage so increase the DT2MS value.

4.With time step -10.500E-0.5:

1.Change the DT2MS value -9.500e-0.5 to -1.020e-0.4 in control time step.

Termination time:

2.The percentage of mass added is 7.4% we cannot get the required percentage so increase the DT2MS value.

5.With time step -10.500E-0.5:

1.Change the DT2MS value -1.020e-0.4 to -1.028e-0.4 in control time step.

Termination time:

2.The percentage of mass added is 7.97% we cannot get the required percentage so increase the DT2MS value.

CASE-2(Mass Scaling in Implict Method):

1.Create the implict card in the control.

2.IMFLAG switching flag set to 1 which means implict analysis.

3.DTO initial time step size for implicit analysis is 1.

IMPLICIT SOLUTION:

IMPLICIT SOLVER:

Step-1:

DT2MS -3.500e-05 is given with TSSFAC 0.9

 

Step-2:

DT2MS -1.028e-04 is given with TSSFAC 0.9

 

    The running time requires to complete the simulation for DT2MS = -3.5E-5 is 2mins and 15 sec and for DT2MS = -1.028E-4 is 2mins 16sec. 

COMPARISION:

EXPLICT ANALYSIS:

Runtime (hrs and mins) Runtime (sec) % increase Runtime (hrs and mins) Runtime (sec) % increase 1 -3.500E-05 30 hrs 36 110216 0 38 hrs 41 mins 139318 0 2 -6.500E-05 22 hrs 47 82052 0.0578 26 hrs 48 96504 0.0578 3 -8.500E-05 16 hrs 50 60607 1.5872 19 hrs 9 68984 1.5872 4 -9.000E-05 17 hrs 1 61280 2.7443 20 hrs 37 74243 2.7443 5 -9.500E-05 14 hrs 31 52313 4.3136 26 hrs 6 94019 4.3136 6 -1.000E-04 21 hrs 43 78182 6.4233 17 hrs 14 62046 6.4233 7 -1.020E-04 18 hrs 48 67737 7.4771 16 hrs 9 58156 7.4771 8 -1.025E-04 21 hrs 50 78640 7.766 21 hrs 26 77162 7.766 9 -1.027E-04 21 hrs 48 78487 7.884 16 hrs 35 59751 7.884 10 -1.028E-04 14 hrs 54 53650 7.9446 56 hrs 55 204947 7.9446 11 -1.029E-04 15 hrs 22 55365 8 16 hrs 22 58978 8 12 -1.030E-04 13 hrs 53 50015 8.06 19 hrs 18 69507 8.06

Iteration	DT2MS	TSSFAC = 0.9			TSSFAC = 0.8

IMPLICT ANALYSIS:

Runtime (Explicit) Runtime (Implicit) 1 -3.500E-05 110216 2289 2 -1.029E-04 55365 2273

Iteration	DT2MS	TSSFAC = 0.9

       

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     From the output, the runtime required to complete the simulation vareis for the different values of DT2MS when using explict analysis whereas the variation in runtime for different values of DT2MS is negligible when using implict analysis.

     As a output,parameters like DT2MS and TSSAFC have no effect on implits runtime.

RESULT:

     Thus the run time using explict and implicit mass scaling to reduce the run time of a model and ensure the stability of mass scaling is performed sucesssfully.