Coil Spring

[Mr. Helio Bailly Guimaraes 0]

Coil Spring is a good example of mixed discrete-integer optimization, see reference: Jouni Lampinen - Ivan Zelinka (1999). "Mixed Integer-Discrete-Continuous Optimization By Differential Evolution, Part2: a practical example". In: Osmera, Pavel (ed.)(1999). Proceedings of MENDEL'99, 5th International Mendel COnference on Soft COmputing, June 9.-12.1999, Brno, Czech Replublic, pp.77-81. ISBN 80-214-1131-7.

 

The model is defined by D - Outer Diameter; d - wire diameter and N - Number of coils.

 

Where:

D is a continuous value.

d is given by an Allowable wire diameters table. The Design variable d refers to an index of the table.

N is an integer value.

Note: the last two design variables can be given as a non-integer value (for the usage of regular optimization processes). The appropriate integer value and allowable wire diameter from the table are defined in the feature "IntegerDiscrete".

 

Regards.

 

 

 

Coil_Spring_Forum.fdb

[Mr. Claus Abt 14]

HI Helio,

 

Nice model! What would be the objective function for the optimization problem? Are there any constraints imposed on the problem?

 

Thank's

Claus

[Mr. Helio Bailly Guimaraes 0]

Hello Claus,

 

The objective function for the optimization problem would be the weight of steel (volume of the spring).

You can find it on the project folder: NumericalExample/toMinimize/ObjFunction

 

There are 8 constraints for this problem concerning maximum load, deflectiong from pre-load etc...

You can find the constraints definition at: NumericalExample/subjectTo

and the inequalities on Optimization tab/ Constraints

 

Details, equations and definitions can be found on the paper Jouni Lampinen - Ivan Zelinka (1999) which can be freely download on-line.

 

Or you can ask me, I will be pleased to give further information about the model and the example.

 

Best regards,