Abstract
One of the most effective methods of treating intravascular formations at present is the use of stepped ultrasonic waveguide systems of a tubular type (concentrators-waveguides) with a hollow spherical tip, the presence of which makesit possible to supply liquid media to the dislocation zone of an intravascular formation with the aim of additional cavitation effect and as efficiently as possible. destroy intravascular formations due to vibration impact. Based on the results of the analysis on the features of the existing shaping methods for obtaining a hollow spherical tip of the concentrator-waveguide, it is advisable to use methods of plastic deformation – expansion and crimping. The paper presents results of preliminary calculations, numerical modeling and experimental studies of tip shaping processes of the concentrator-waveguide by distribution and crimping. On the basis of the finite element method in the environment of the ABAQUS software package, modeling of the expansion and crimping of a pipe billet was carried out, which has made it possible to: evaluate the stress-strain state of the deformable conical section of the billet, the change in wall thickness during the forming process and calculate the length of the billet for the design of the conical section; to establish the patterns of the influence of geometric parameters on the power modes of the distribution process; to set the parameters of the modes of forming the tip of the concentrator-waveguide by the method of distribution and crimping, which ensure the formation of the required geometry. The obtained results of preliminary calculation, numerical modeling and experimental studies of tip shaping processes of the concentrator-waveguide by distribution and crimping have similar values, which confirms the correctness of using both the method of preliminary calculation and numerical modeling in the development of the technology for manufacturing the concentrator-waveguide.
Highlights
One of the most effective methods of treating intravascular formations at present is the use of stepped ultrasonic waveguide systems of a tubular type with a hollow spherical tip, the presence of which makes
On the basis of the finite element method in the environment of the ABAQUS software package, modeling of the expansion and crimping of a pipe billet was carried out, which has made it possible to: evaluate the stress-strain state of the deformable conical section of the billet, the change in wall thickness during the forming process and calculate the length of the billet for the design of the conical section; to establish the patterns of the influence of geometric parameters on the power modes of the distribution process; to set the parameters of the modes of forming the tip of the concentratorwaveguide by the method of distribution and crimping, which ensure the formation of the required geometry
Поступила 27.01.2021 Подписана в печать 23.03.2021 Опубликована онлайн 30.03.2021
Summary
Раздача – формоизменяющая операция для увеличения периметра трубной заготовки растяжением изнутри в радиальном направлении пуансоном. Обжим – сужение поперечного сечения концевой части трубной заготовки в радиальном направлении в матрице путем обжатия материала снаружи и уменьшения диаметра Где Dр – наибольший диаметр после раздачи; D – исходный диаметр заготовки. Где sр – толщина стенки после раздачи; s – толщина стенки исходной заготовки. Для формирования сферического наконечника из трубки диаметром 1,0 мм требуется предварительная раздача заготовки до диаметра 1,35–1,37 мм (с учетом припуска под последующие операции финишной обработки). Обжим заготовки после раздачи в выпуклую сферическую форму необходимо производить в матрице с радиусом закругления 0,65–0,70 мм. Количество переходов, необходимых для раздачи трубчатой заготовки диаметром 1,00 мм до диаметра 1,36 мм, оценивалось с использованием коэффициента раздачи Kp по формуле (1). Диаметры пуансонов определяли как разность диаметра Dр и толщины стенки sp.
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