Analysis of Stress-Strain State (Sss) of Billet Material in the Course of Setting by Resource-Saving Method of Roll Stamping

Abstract

The processes of planting blanks by the rolling stamping method allow for the efficient production of a wide range of high-quality products, but the possibility of material destruction during deformation prevents the expansion of their technological capabilities. Further development of the processes is possible through the development of new technological schemes based on the analysis of deformation kinematics and the appointment of favorable technological parameters, taking into account their influence on the stress-strain state and deformability of the material of the workpieces. In order to widely use the method of assessing the deformability of workpieces, a reliable technique is needed, which provides for the presence of a mathematical model of the trajectory of deformation of material particles in the coordinates "stress state indicator - accumulated plastic deformation before failure." The work uses an approach to finding an analytical representation of the deformation trajectory based on the construction of a differential equation between the components of plastic deformation increments, followed by the solution of this equation and the identification of its parameters based on experimental data. According to the results of the research, the deformation trajectories of the material particles of the peripheral surface of the flange when planting by rolling stamping method were schematically constructed in the coordinates "intensity of deformations - stress state indicator". Based on the built model, damage accumulation can be simulated by changing the values of the model parameters for different materials and deformation paths. An analytical representation of the deformation trajectory in a parametric form was obtained. The advantages of representing the deformation trajectory in the form of parametric equations are the convenience of analyzing these trajectories. The advantage of the model of the trajectory of deformation of material particles in the coordinates "stress state indicator - plastic strain accumulated before failure" is the absence of a material constant in the analytical expression for the stress state, and the consequence is additional convenience of analyzing ratios and selecting the value of the material constant based on experimental data. Key words: rolling stamping, flange landing, stress-strain state, mathematical model of the deformation trajectory.

Investigation of Stamping by Wrapping Processes Through Material Deformation Modeling Analysis

“…В працях С. І. Сухорукова, І. О. Сивака запропоновано аналітичні представлення поверхні граничних деформацій, зокрема трипараметричний вираз [1,2] Автор [7] вважає, що використання параметра Лоде, як другого показника під час характеристики об'ємного напруженого стану, не є достатньо обґрунтованим, оскільки цей показник не залишається незмінним при плоскому напруженому стані. І як більш теоретично обґрунтований пропонує використовувати показник  :…”