(Warning: the current definition of the loudspeaker has some conflicts between the documentation and the actual model. Please refrain from using the model until I can correct these problems.)
This model is inspired on the loudspeaker design example originally proposed by Infolytica Corporation. The objective of this problem is the minimization of the total volume of material used, subject to the generation of a given magnetic flux density in the air gap defined by variable x9.
This problem can also be very easily turned into a multiobjective optimization example, by considering the minimization of volume and the maximization of the magnetic flux density.
Cheers,
Felipe