PSI - Issue 40

Aleksandr Zalazinskiy et al. / Procedia Structural Integrity 40 (2022) 461–469 Aleksandr Zalazinskiy at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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selected (14) for each chromosome. A new population of chromosomes (N=9) is created, composed of the genes of the best chromosomes of the previous generation. In this population, the genes of chromosomes with the worst fitness function (N=6) undergo mutations (random changes in the values of λ , α , f within 0.5 – 15%), then the suitability of each newly created chromosome is calculated, after which the cycle repeats, as a result, one best chromosome is selected, giving a minimum of the generalized criterion F (13). The number of cycles leading to a satisfactory result turned out to be 20, after which their increase did not lead to an improvement in the result (Dvoynikov, 2021). As an alternative, a deterministic solution search was also performed, giving the same accuracy, which required 10 6 cycles. As a result of HMP modeling, a compromise solution to the problems of minimizing the pressing force, inhomogeneity of the deformed state, and damage to blanks and products of the procurement production of composite materials is provided. The use of the expert system made it possible to determine the dependence of the generalized HMP quality criterion on the main technological parameters, which include:  – the extrusion ratio, the angle of the cone of the deforming which depends on the choice of the medium of the visco-plastic coating of the pressed workpiece. The results of the multi-criteria selection of the varied parameters of the HMP allow recommending the following values of the technological parameters of the process under study: the hood = 10 ; the angle of the cone of the matrix = 30 ̊ . The composition of the working medium that creates pressure on the workpiece during pressing is selected so that at the pressing temperature, the friction of the workpiece and the deforming tool corresponds to the coefficient of friction ≈ 0.19 or is based on technological conditions. 5. Conclusion Using the example of studying the HMP of a bimetallic electrically conductive composite of the Nb-Ti+Cu system used to manufacture windings for powerful electromagnets of energy complexes, the paper proposed a methodology for multi-criteria selection of rational values of technological parameters. The modeling and multi-criteria optimization of the process under study provide a compromise solution to the problems of minimizing the pressing force, non-uniformity of the deformed state, and damage to the products of the blank production of metal matrix composites of a fibrous structure. To solve the problem of multi-criteria selection of technological parameters, an expert system using a genetic algorithm was used. The performed research opens up new opportunities for improving the processes of pressure treatment of composite materials. References Avitzur, 1965. B. Hydrostatic extrusion. ASME J Eng Ind, 487 – 494. Baque, P., Pantin, J., Jacob, G. 1975. Theoretical and experimental study of the glass lubricated extrusion process. J. Lubr. Tech. Trans. ASME, 18 – 24. Byon, S.M., Hwang, S.M. 1997. Die shape optimal design in bimetal extrusion by the finite element method. J. Mater. Process. Technol., 67, 24 – 28. Byvaltsev, S.V., Zalazinskiy, A.G., Polyakov, A.P. 2008. Experimental and analytical method of calculation of the composite damage during extrusion. Russian Journal of Non-Ferrous Metals, v. 49, no. 4, 241 – 246. Composite materials. V.2: Mechanical composite materials. 1974. New York and London, ACADEMIC PRESS, pp. 503. Draper, N.R., Smith, H. 1998. Applied Regression Analysis, New York etc., John Wiley & Sons, INC., cop., pp. 736. Dvoynikov, D.A., Zalazinskiy, A.G., Titov, V.G. HMP GA 1. Certificate of state registr ation of a computer program. RU № 2021667503, 19.10.2021. Date of state registration in the Register of computer programs 29.10.2021. Hongbo, Y., Yinghong, P., Xueyu R., Mingxia, L. 2005. A finite element model for hydrodynamic lubrication of cold extrusion with frictional boundary condition. J. Mater. Process. Technol., 161, 330, 440-444. Hwang, Yeong-Man, Hwang, Te-Fu. 2002. An investigation into plastic deformation behavior within a conical die during composite rod extrusion. J. Mater. Process. Technol., 121, 226 – 233. Johnson, W., Kudo, H. 1962. The Mechanics of Metal Extrusion. Manchester University Press, pp. 226. Kang, C.G., Jung, Y.J., Kwon, H.C. 2002. Finite element simulation of die design for hot extrusion process of Al/Cu clad composite and its experimental investigation. J. Mater. Process. Technol., 124, 49 – 56. Kolmogorov, V.L. 1970. Stresses, deformations, destruction. Moscow, Metallurgiya Publ., pp. 230.