Development of multiaxial warp knitting technology for production of three-dimensional near net shape shell preforms

Abstract

The possibility of direct preforming in the near net shape of final component structure with load-and shape-conforming fiber orientations is highly essential in composite production, not only to reduce costs but also to attain better mechanical properties and form stability. Based on the concept of varying the reinforcement yarn lengths during the feed-in (warp yarn delivery) and segmented doffing, synchronous working numerically controlled warp yarn delivery and doffing machine modules have been newly developed for multiaxial warp knitting machines to create a resource efficient textile process chain by a single-step, large-scale oriented production of load-and form-conforming warp knitted three-dimensional shell preforms with free-form geometrical surfaces. Such customized preforms in the near component net shape offer higher material utilization and increased lightweight potential.

Textile reinforcement structures for concrete construction applications––a review

“…208 Based on such bi-and multiaxial grid-like NCFs, Sankaran et al developed a numerically controlled delivery and doffing system for the multiaxial warp-knitting technology to produce grids with variable warp yarn lengths, which enables the production of 2D reinforcement textiles adapted for specific curved 3D shapes, such as the shells of a pavilion. 74,[209][210][211] Spacer fabrics. Warp-knit spacer fabrics are produced using double-bar raschel machines producing two layers of a warp-knit textile connected by spacer yarns.…”

Collaborative research on carbon reinforced concrete structures in the CRC/TRR 280 project

“…In the two projects, the focus is on the development of textiles and textile technology. In one, biologically inspired load‐adapted 3D textile reinforced structures 33 with spatial branching–in other words, 3D preforms adapted to the geometry and load–will be developed. The load‐adapted 3D textiles are to be used above all in the additive manufacturing of carbon reinforced concrete.…”

Standortübergreifende Forschung zu Carbonbetonstrukturen im SFB/TRR 280

“…Textiltechnologien im Fokus. Zum einen werden biologisch inspirierte, lastangepasste 3‐D‐Textilbewehrungsstrukturen [33] mit räumlicher Verzweigung, d. h. geometrie‐ und lastgerechte 3‐D‐Preforms, entwickelt. Diese lastangepassten 3‐D‐Textilien sollen v. a. in der untersuchten generativen Fertigung von carbonbewehrtem Beton zum Einsatz kommen.…”