Stretching during axisymmetrical forming of sheet metal

Simultaneous Deep Drawing and Stretch Forming of Knitted Fabric Composite Sheet

“…Figure 1 shows a typica structure of weft-knitted fabrics. This paper explores the possibility of optimizing the cup height formation by means of flange draw-in during sheet stretching, hence simultaneous deep drawing and stretch forming Contrary to earlier analysis [9], a generalized sheet forming process do not lie between pure deep drawing (marked by absence in surface area increase) and pure stretch forming, but rather between negative stretching (indicated by decrease in surface area) and pure stretch forming, as shown in Table 1. Expression of sheet formability by the X-factor criteria can be achieved through variation of forming conditions such as the blank holder force, tool profile and workpiece dimensions.…”

“…the cup wall may be assumed vertical. As in any shell of revolution, the surface area is obtained through the following integration (7) to give a simple shell area expression (8) (9) for H<(Rn+Rs).…”

“…(8) and (9 (17) where r is the radial distance of a grid node from the cup axis and h is the height of the grid node from the cup base.…”

Stretch Forming Analysis of Knitted Fabric Composites

“…2 with R p , R t and R s being the hemispherical punch, die throat and die shoulder radii respectively. The cup wall length, L, is expressed as [5] where the contact angle, b , is:…”

Deep Drawing of Plain Weft-Knitted Fabric Composites: Part 1.: Cup Height Analysis

“…An idealised plain weft-knitted fabric structureAt the macroscopic viewpoint, overall meridional stretching is defined, based on the deformed sheet shown inFig.2, as more practically in terms of cup height (H) and tool profile as contact angle, b, is modified from Qin et. al [21]. to give…”