Mr. Helio Bailly Guimaraes 0 Report post Posted August 16, 2013 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 Share this post Link to post Share on other sites
Mr. Claus Abt 14 Report post Posted August 16, 2013 HI Helio, Nice model! What would be the objective function for the optimization problem? Are there any constraints imposed on the problem? Thank'sClaus Share this post Link to post Share on other sites
Mr. Helio Bailly Guimaraes 0 Report post Posted August 16, 2013 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/subjectToand 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, Share this post Link to post Share on other sites