Simulation of the stress-strain state of a tubular billet during the expansion of its middle part using rigid die

В работе представлены результаты моделирования в конечно-элементном программном комплексе ANSYS напряженно-деформированного состояния тонкостенной трубчатой заготовки из титанового сплава ОТ4 в процессе раздачи эластичной средой по жесткой матрице. Рассматривается осесимметричная матрица в виде тела вращения с криволинейной образующей. Задача решается в осесимметричной квазистационарной постановке. Конечно-элементная модель включает пуансон, матрицу, трубчатую заготовку, и эластичное рабочее тело. Пуансон перемещается в вертикальном направлении вниз, передавая усилие на деформируемую деталь через рабочее тело. Фрикционное взаимодействие происходит по закону Кулона. Проведен анализ напряженно-деформированного состояния детали в процессе формообразования. Исследовано распределение остаточных напряжений, упругое пружинение после снятия нагрузки и утонение стенок детали. Показана возможность получения детали типа «переходник» из титанового сплава ОТ4 холодным пластическим деформированием без нагрева заготовки. In this paper, the results of simulation of the stress-strain state of a thin-walled tubular blank made from titanium alloy OT4 in the ANSYS finite element software package in the process of expansion by an elastic medium in the rigid die are presented. The axisymmetric die in the form of a body of revolution with a curvilinear generatrix is considered. The problem is solved in an axisymmetric quasi-stationary setting. The finite element model includes a punch, a die, a tubular blank, and an elastic working body. The punch moves vertically downward, transmitting the force to the deformed tube through the working body. Frictional interaction occurs according to the Coulomb's law. The analysis of the stress-strain state of the deformed detail in the process of shaping is carried out. Distribution of residual stresses, elastic spring back after removal of the load and wall thinning of the detail are investigated. The possibility of obtaining the "adapter" type detail from titanium alloy OT4 by cold plastic deformation without heating the blank is shown.

Simulation of Compound Bulging Process for T-Branch Tubes Using Rubber Medium

To determine the optimum process parameters and loading paths for T-branch tube compound bulging using rubber medium, a finite element model was established at the software platform of ANSYS/LS-DYNA. Tubular blank parameters were optimized while the affections of blank parameters and frictions in bulging process were analyzed, during which Taguchi method, sensitivity analysis and normalization method were adopted and an evaluation function is inducted. The Taguchi method was used to establish a design of simulation schemes, and numerical simulations were carried; a sensitivity analysis was carried out with analysis of variances to seek the significance of parameters; the evaluation function was inducted to synthetically evaluate the affections of the thickness variation and the branch height and normalization method are applied to ensure equality of two sets of data in the evaluation function. Then the execution method and loading path of counter force for compound bulging process were designed and an ideal T-branch tube was gained at last.