Mechanics and Advanced Technologies, Vol. 9, No. 1(104)

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https://ela.kpi.ua/handle/123456789/73437

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Перегляд Mechanics and Advanced Technologies, Vol. 9, No. 1(104) за Ключові слова "621.7.044.4+539.374"

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    Modelling of the process of interaction of multi-impulse local loading at electrohydraulic forming of large-dimensional bottoms
    (Igor Sikorsky Kyiv Polytechnic Institute, 2025) Taranenko, Mykhaylo; Naryzhniy, Olexandr
    Forming of large-dimensional thin-sheet bottoms usually leads to great complexity of technological processes. When forming is conducted on mechanical presses using male- and female dies one can observe phenomenon of loosing stability of bottom shape with uniform through perimeter movement of the workpiece flange during drawing and large areas of thin workpiece that do not support by rigid surfaces of the die and are prone to be loaded with compressive stresses. This leads to the formation of folds and corrugations on the flange and dome part. Application of presses for stamping with elastic media and high pressure is irra-tional from energy considerations, because different parts of the workpiece require different pressures for their shaping. Electro-hydraulic (EG) forming is more effective when stamping such parts occurs consequently by zones of the workpiece and require different loading at each zone. It is possible to implement sequence control and load locations on multi-electrode EG-presses. Objective of the presented research was, on the one hand, to study the possibility of the formation of pulsed submerged flows of liquid medium, that transmits the load, their interaction with each other and the deforming workpiece in the technological zones of EG presses, and on the other hand, the possibility of using the LS Dyna software in combination with ALE method. To achieve the specified goal, methods of mathematical modeling of forming processes and interaction of deformed environments having different mechanical parameters were used, as well as experimental methods to confirm the processes being studied. The results obtained consider the possibility of creation of high energy-containing immersed jets of liquid, their interaction between themself and the deformable workpiece depending on the technological pa-rameters. The parameters of the workpiece deformation process were studied. It is shown that blank shape change has a wave-like character and, by changing the temporal and spatial parameters of the load, it is possible to control the parameters of the blank stress-strain state. Comparison of simulation results with experimental data substantiated the possibility of using the proposed modelling method in the study of pulsed flows in heterogeneous media. The conclusions state the achievement of the mentioned goal, describe the mechanism of interaction of liquid jets in the case of energy concentration necessity in the given zones of the workpiece and the possibility of changing the direction of energy flows when the moment of the of EG discharges beginning in adjacent discharge cavities is changed. The accuracy of the simulation results was assessed when compared with experimental data.