Ring Winding Technology: Increased Process Efficiency and Effects on the Mechanical Properties of Ring Specimens

Abstract

For automotive applications high pressure storage of compressed hydrogen (CH2) becomes more and more important especially regarding the future sustainable mobility based on renewable energy. The filament winding technology is highly industrialized today to meet the requirements for a high-quantity production of lightweight fiber reinforced pressure vessels used for hydrogen-powered cars using fuel cells or combustion engines. However, the main disadvantage of the conventional wet winding process is the low lay-down rate. A decrease of the cycle time to increase the production rate can be realized by the simultaneous feed of a large number of rovings circumferentially arranged around the mandrel. A team of engineers at the Institut fuer Verbundwerkstoffe (Institute for Composite Materials) now further developed the ring winding technology to manufacture pressure tanks with a diameter up to 500 mm (20 inch) with fully wrapped dome sections. This large ring winding head with 12 radial movable arms and multiple payout eyes allows an accordingly higher material output and reduces the cycle time significantly. The profitability analysis considering ring winding head configurations with different number of feed-eyes show the optimization potential regarding the reduction of the production costs of FRP pressure cylinders. A critical review regarding reachable process efficiency is also given in this paper. A modified “tube siphon impregnation unit” is the most important component of the ring winding head due to its compact and modular design. This clean impregnation of 48 carbon fiber rovings near the winder minimizes possible resin leakages. In comparison to a conventional resin bath the amount of hazardous waste, for example contaminated acetone, can be reduced. FRP laminates (fiber reinforced plastic) with a reduced number of crossing points and less ondulation of fiber bundles result higher load bearing capacity and increased mechanical properties. Regarding the degree of interweaving the multi feed-eye configuration of a ring winding head makes it more challenging to define an optimized winding pattern with the given winding angle. The split disk test method was used for comparative investigations regarding the influence of undulations on the material properties of filament wound laminates.

Path calculation, technology and opportunities in dry fiber winding: a review

“…This enables high-speed winding and production time is reduced significantly. Paessler et al [62], developed a ring winding technology which can simultaneously lay a large number of rovings circumferentially around a mandrel. The ring winding head consists of 12 radial movable arms and multiple payout eyes.…”

The effect of processing on the microstructure of hoop-wound composite cylinders

“…Thereafter, four other cylinders were produced, employing a new impregnation system (Figure 1(b)). This system uses a closed sinusoid-shaped tube without moving parts, a device motivated by Paessler et al 8 and Miaris et al [9][10][11] The rationale for the new design stems from the search for novel solutions for faster and better-controlled production. Cylinders of 4-layer and 24-layer thickness were wound using the new system.…”

“…One remarkable design is the ring-winding technology. 8 This system has multiple pay-out eyes and a specific impregnation unit as an important manufacturing innovation. [9][10][11] A good potential for high material output, reduction of production costs and a better control over the process compared to conventional winding has been reported.…”

“…[9][10][11] A good potential for high material output, reduction of production costs and a better control over the process compared to conventional winding has been reported. [8][9][10][11] A different set of modifications, referred to as 'clean filament winding', have also been reported in detail. [12][13][14][15][16][17] The reduction of waste (resin, solvent) and fewer emissions to the atmosphere are emphasized in these works.…”

“…Previous image analysis work had identified that through-thickness trends in microstructure were rather mild, if present at all. 8 and Miaris et al 9,10 The saturation and the brightness were slightly modified in all images, and the micrographs were converted to greyscale (Figure 2(a) and (b)). A typical histogram of a greyscale image is shown in Figure 2(c), where different material phases are distinguished by different levels of grey.…”