2.3.1. Sensitivity Analysis

The sensitivity analysis is based on the approach of the local sensitivity analysis in [9,10] and is carried out on the basis of the given initial design of the IM. For this purpose, the individual geometric parameters of the machine are varied by user defined factor *r*sens. A change that is too small leads to numerical instabilities and changes that are too large possibly lead to inconsistent machine geometries. If the sensitivity to a geometry parameter is to be examined, the influence of this parameter on other geometry variables must also be taken into account. These influences are described using a correlation matrix, which describes for each possible variable geometry parameter which other geometry parameter still has to be changed. Both machines, the initial design and the slightly changed machine geometry, are simulated and the influence on the objective function is assessed by comparing the output variables.
