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In this paper we propose a genetic programming approach to predict radial stress distribution in cold-formed material. As an example, cylindrical specimens of copper alloy were forward extruded and analysed by the visioplasticity method. They were extruded with different coefficients of friction. The values of three independent variables (i.e., radial and axial position of measured stress node, and coefficient of friction) were collected after each extrusion. These variables influence the value of the dependent variable, i.e., radial stress. On the basis of training data set, various different prediction models for radial stress distribution were developed during simulated evolution. Accuracy of the best models was proved with the testing data set. The research showed that by proposed approach the precise prediction models can be developed; therefore, it is widely used also in other areas in metal-forming industry, where the experimental data on the process are known.

Genetic programming method for modelling of maximum height of deep drawn high strength sheet materials is proposed in this paper. Genetic programming (GP) is an evolutionary computation approach which uses the principles of Darwin's natural selection to develop effective solutions for different problems. The aim of the research was the modelling of cylindrical cup height in deep drawing process and analysis of the impact of process parameters on material formability. High strength steel sheet materials (DP1180HD and DP780) were formed by deep drawing using different punch speeds and blank holder forces. The heights of specimens before cracks occur were measured. Therefore, four input parameters (yield stress, tensile strength, blank holder force, punch speed) and one output parameter (cup height) were used in the research. The experimental data were the basis for obtaining various accurate prediction models for the cup heights by the genetic programming method. Results showed that proposed genetic modelling method can successfully predict fracture problems in a process of deep drawing.