Large ellipsoid parts manufacture using electromagnetic incremental forming with variable blankholder structure

Xiaohui Cui,Zhihao Du,Baoguo Chen,Hailiang Yu,Ang Xiao,Ziqin Yan

doi:10.1007/s00170-021-07695-y

Abstract

Large ellipsoid parts are prone to wrinkle when forming by using traditional stamping. Aiming to solve the wrinkling problem in large parts, the EMIF method with a variable blank holder is proposed in this paper. The numerical simulation has shown that the sheet material near the blank holder is, as a consequence of stamping, subjected to circumferential compressive stress. When the drawing height was 100 mm, the sheet metal was notably wrinkled. In the electromagnetic forming (EMF) process, the sheet region facing the coil becomes thinner. However, the sheet metal thickness corresponding to the coil edge increases with the increase in forming height. If the EMF forming height is 150 mm, the sheet, which is in contact with the smooth mold, is deformed without a wrinkle. Compared to traditional stamping, the EMF can significantly reduce the sheet metal wrinkling, improving the deformation height of the sheet metal smooth area.

Highlights

With the increasing demand for high-speed trains, large aircraft, and large carrier rockets requiring integral, high-precision, and lightweight structural parts, the sheet parts are developing rapidly
The large ellipsoid parts are the main load-bearing components in the rocket tank, which are prone to wrinkle when using the traditional stamping
In order to solve the wrinkling problem in large parts, the electromagnetic incremental forming (EMIF) method with a variable blank holder is proposed in this paper

Summary

Introduction

With the increasing demand for high-speed trains, large aircraft, and large carrier rockets requiring integral, high-precision, and lightweight structural parts, the sheet parts are developing rapidly. The accurate springback prediction is another problem encountered when using creep aging [5,6] For this reason, the traditional rocket tank manufacturing process by using melon petal forming and welding generally has low manufacturing efficiency and poor performance. The traditional rocket tank manufacturing process by using melon petal forming and welding generally has low manufacturing efficiency and poor performance Regarding the latter, the use of heavy equipment to produce the large parts (2), China's largest vertical spinning machine with (1000 kN capacity) has the following dimensions: it is 30 m long, 18 m wide, and stands 13 m tall [7]. The numerical simulation and the experiment were carried out to analyze the forming process and wrinkling in large parts, both in traditional drawing and EMIF process

Forming Principle

Wrinkle simulation

Finite element model

The Experiment

Findings

Conclusions