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.

Composites have now revolutionized most industries, like aerospace, marine, electrical, transportation, and have proved to be a worthy alternative to other traditional materials. However for a further comprehensive usage, the tailorability of hybrid composites according to the specific application needs on a large-scale production basis is required. In this regard, one of the major fundamental research fields here involves a technology development based on the multiaxial warp-knitting technique for the production of bionic-inspired and application-specific textile preforms that are force compliant and exhibit multi-material design. This article presents a newly developed yarn (warp) path manipulation unit for multiaxial warp-knitting machines that enables a targeted production of customized textile preforms with the above characteristics. The technological development cycle and their experimental validation to demonstrate the feasibility of new technology through production of some patterns for different field of applications are then discussed.

Spatial three-dimensional (3D) stitch-bonded preforms offer a huge potential and an optimal utilization of the fiber mechanical properties for their usage in various technical applications. These preforms form an efficient alternative to the existing two-dimensional textile preforms due to their load-bearing fiber orientation offered by their geometrical configuration. The fundament of this research activity, based on the stitch-bonded technology, is the development of a new processing solution for producing 3D spatial open stitch-bonded textile preforms with minimal processing stages. Based on a newly developed concept with variable warp yarn delivery and differential doffing, this technology is principally enhanced so that various helical, circular and curved grid structures, along with 3D spatial structures, could be produced on a single machine with minimal setup, which hitherto has not been realized with any other existing processing technique. These novel form-based textile preforms are found to be suitable for application as reinforced components in complex spatial composites with a mineral or a plastic-based matrix, wooden composites and elastomers.

Textile high-performance filament yarn subjected to extremely high thermal loads can be found in various technical application fields. Besides the mechanical loads, textile fiber materials have to also satisfy high safety requirements in these applications with respect to thermal loads. Some of the main fields of application in the field of mechanical engineering are turbines, drive devices, rocket components and fire protection coatings. Textile grid-like structures are also being increasingly used in civil engineering as reinforcements (textile concretes). The design and development of textile structures for these applications demands studying and acquiring the material behavior under high thermal loads. Neither sufficient data nor standardized testing methods have been extensively achieved for evaluating the tensile characteristics of filament yarns under thermal influences. Hence, studying the thermal behavior of these yarns, which are used as input material for the reinforcing structures, is essential. The impact of the standard atmospheric condition on the oxidation behavior of the yarns, as in the case of carbon filament yarns and their influence on the physicochemical and tensile mechanical properties, have to be studied as well. This paper aims to address this issue and provides an insight into the current research about the development and realization of a novel test stand and the subsequent study of tensile mechanical behavior for textile high-performance fiber material under extreme thermal loads together with their physicochemical behavior.

Fiber-reinforced composites used in numerous technical applications have to meet the ever increasing safety requirements. Resistance to extreme stress under high velocity impact loads assumes even greater significance. Previous studies on the behavior of fiber-reinforced composites under impact loads provide little insight about the properties of filament yarns, a basis for many composite applications. Hence this paper focuses on the development of a suitable test method for performing high speed tensile tests on all filament yarn types, and the acquisition and analysis of the test results. This will enable the derivation of material models for their usage in the field of composites applications. Initially, the widely used carbon fiber filament yarns have been tested. The conclusive test results with a reduced yarn clamp mass and high stiffness of the test apparatus indicate that tensile strength and modulus of elasticity of carbon filament yarns increase with higher strain rates.