Multi-simulation : Skew rate effect

The multisimulation environment allows to automatically generate design configurations in a combinatorial way, launch the simulations and analyse the results (e.g. correlation analysis). Both continuous and discrete design variables can be handled, and several response functions can be evaluated.

Here the effect of rotor skew rate on acoustic noise and electromagnetic torque at variable speed (based on the ideal sinusoidal constant slip sonogram).
A new project is set-up in tuto_test_SCIM_12.m by copy/paste tuto_test_SCIM_05.m (loaded sinusoidal simulation) or by loading it with the GUI. The skew is activated as in previous project with

Input.Simu.type_skew = 1;
Input.Simu.Nskew_slices = 8;

The sensitivity analysis is activated:

Input.Simu.type_sensitivity = 1;

The design variable skew_rater is selected


As we want a continuous variable randomly taken in an interval as an input, one puts

Input.Simu.types_var=[0]; % Continuous values
Input.Simu.types_val=[0]; % Value in an interval

To make the skew rate in stator slot pitch vary between 0.8 and 1.4, the boundaries are defined as :

Input.Simu.bds_contvar={[0.9 1.396]};

To generate 10 different skew rate one defines


The 10 values will be defined as a linespace of this interval:

Input.Simu.type_sampling = 0;

To look at the torque and the maximum sound power level at variable speed (ideal sonogram) one should specify


With the GUI, all these parameters are set in Workflow Sensitivity/ Optimization. First select "Sensitivity : All possible values" (it will test every single combination of the input, as we only have one input, it will create only 10 simulations). Then click on "Add Input" to set skew_rater:

360. Setup of a sensitivity input with the GUI
Setup of a sensitivity input with the GUI

Then click twice on "Add Output" and complete the new fields.

360. Setup of a skew sensitivity analysis with the GUI
Setup of a skew sensitivity analysis with the GUI

Note that you can edit input by clicking on its text and remove input or output by clicking on the corresponding red cross.

The project is launched as a standard project. A fixed speed simulation is always initialized before the sensitivity analysis. The text output gives the total number of simulations and the estimated maximum simulation time:

270. Text output
Text output

All the post processing of the multi-simulation (MS) environment start with "plot_MS" and can be easily found using matlab autocompletion.

plot_MS_all_resp_var allows to display all the response variables for each simulation:

270. LwrA = f(skew_rater)
LwrA = f(skew_rater)
270. Cout = f(skew_rater)
Cout = f(skew_rater)

One can see that the torque is reduced due to rotor skew, and that the sound power level as a minimum close to one rotor slot pitch.

The correlation factors between the design variables and the output variables can be calculated and displayed using plot_MS_correlations

270. Correlation matrix
Correlation matrix

One can see that the skew has a higher influence on the noise rather than on the average torque.

Previous Next