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Modelling and Simulation of reinforcement textiles to predict the draping behavior

Modelling and Simulation of reinforcement textiles to predict the draping behavior

The demand for lightweight materials is rising due to a growing awareness for environmental issues and legal obligations. Fiber reinforced polymers (FRPs) are among the most desirable lightweight materials, due to the high mechanical property-to-weight-ratio in comparison to other materials like aluminum. The widespread use of FRP is currently prevented by the high costs which emerge within the process chain of FRP. About 50% of total part the cost is originated within the preforming. During preforming the textiles are stacked, jointed and formed into near-net shape. Usually the trial-and-error is used during the design of the forming process. Within the trial-and-error, a textile which fits the mechanical requirements is produced, stacked and formed. The previously mentioned steps are repeated, if the processing results in errors like gaps or wrinkles in the textiles.

The goal of the research presented in this article is to reduce the trial-and-error method through the application of a virtual textile design, which is utilized to predict the draping behavior of the textile in advance of the textile production.

To achieve the goal, a novel meso-scale textile model is developed. Inputs for the textile are roving material properties like axial stiffness or friction behavior. With the model, a virtual shear frame test is conducted. The results of the test are used to evaluate the draping behavior of the textiles. Further, the modelling method can be utilized to virtually investigate material properties (e.g. shear, tensile) of different textile patterns or gaps sizes from woven and non-crimp fabrics. This digital twin can be used to preliminarily design the textile without an expensive textile production including trial-and-error, which could result in wasting expensive materials. Additionally, material properties of rovings, e.g. friction values or tensile stiffness, can be changed to investigate the influence on the textile properties.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen University | Virtual Shear Frame Test

Contact

Stefan Hessler

Portrait AZL NeswLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23449
Mail: stefan.hesseler@ita.rwth-aachen.de

 

InnoGrip - Development of an innovative clamping solution for the tensile testing of impregnated and
non-impregnated reinforcement Fibre rovings used for lightweight construction.

InnoGrip – Development of an innovative clamping solution for the tensile testing of impregnated and non-impregnated reinforcement Fibre rovings used for lightweight construction.

Lightweight construction is achieved through the use of new lighter Fibre composite materials, a load path and material-oriented design and functional integration. Precise material characterization is of central importance for a material-oriented design. There are many different test methods for determining the various characteristic values of Fibre composite materials. A characteristic value that is often relevant for the design is the tensile strength of a material on the roving level. There are several different test specifications for determining the tensile strength on the roving level. Which method can be used depends on various factors, such as the Fibre material or the impregnation state of the roving.

At present, there is no testing method that is suitable for all types of reinforcement Fibre rovings and different impregnation states. The multitude of test procedures leads to several problems. First of all, a test laboratory must procure and stock several different test fixtures in order to be able to perform tests on different reinforcement Fibre rovings. Which leads to high investment and storage costs. In addition, the characteristic values determined with the various processes are not easily comparable with each other.

The project InnoGrip aims to develop a single clamping solution that allows different types of reinforcement Fibre rovings to be clamped and tested efficiently without damage. Furthermore, based on the clamp, a test method will be developed that allows fast and efficient testing of reinforcement Fibre rovings independent of the impregnation state or material (glass or carbon rovings).

After successful validation of the developed clamp functionality and the test method through comparison with existing competitive testing techniques, the clamp will not only offer advantages in investigation and development of reinforcing Fibre rovings to Fibre manufacturers, manufacturers of coating and impregnation materials and component manufacturers, but also will aid in continuous incoming and outgoing inspection of parts due to the intended short test cycles.

The collaborative project between Grasse Zur Ingenieurgesellschaft mbH and ITA of the RWTH Aachen University is funded by the BMWI within the ZIM program.

AZL Partner ITA of RWTH Aachen

© Grasse Zur | Composite testing at Grasse Zur

Contact

Felix Pohlkemper

Portrait AZL NewsLIGHT neu

Research Associate | Reinforcing Fibers
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0)241/80 224 22
Mail: felix.pohlkemper@ita.rwth-aachen.de

Shantanu Bhat

Portrait AZL NeswLIGHT

Research Associate | Construction Composites
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80-24741
Mail: shantanu.bhat@ita.rwth-aachen.de

 

CarboYarn - Spinning processes for rCF Staple Fiber Yarn

CarboYarn – Spinning processes for rCF Staple Fiber Yarn

Specific material recycling of rCF processing them into staple fiber yarns for structural fiber composite applications

The use of carbon fiber reinforced plastics (CFRP) in the aerospace and automotive industries, as well as in the mechanical engineering sector, is increasing steadily. As a result, the number of end-of-life (EoL) components to be recycled will also rise substantially in the years to come.

A one-time use of CF results in a significantly worse CO2 balance compared to the use of steel or aluminium. Closing the CFRP material cycle is therefore an indispensable and crucial prerequisite both economically and ecologically. By closing the material cycle the resource and energy efficiency of CFRP is increased.

An alternative to conventional recycling methods is offered by the approach of spinning rCF into staple fiber yarns in combination with thermoplastic matrix fibers. Staple fiber yarns allow a higher orientation of the individual fibers compared to nonwovens. In this way, the high structural-mechanical performance potential of rCF in composite applications can be largely maintained and downcycling of the fiber properties prevented.

In the presented research project AiF CarboYarn rCF are opened, mixed and banded on a carding machine. Next the fiber slivers are stretched on a draw frame. Afterwards, rCF staple fiber yarns are produced using four different spinning processes:

  • Ring Spinning
  • Rotor Spinning
  • Friction Spinning
  • Hollow Spindle Spinning

Finally, the manufactured yarns are mechanically tested and evaluated. The individual work steps for the realisation of the above-mentioned objectives are shared between the research institutions

  • Institut für Textiltechnik (ITA) of the RWTH Aachen University
  • Institut für Textil- und Verfahrenstechnik der Deutschen Institute für Textil- und Faserforschung (DITF), Denkendorf
  • Institut für Textiltechnik Augsburg gGmbH, Augsburg

Within the scope of this project pyrolysed fibers as well as cut fibers were processed. By means of friction spinning, all source materials were successfully spun into hybrid yarns consisting of rCF staple fibers and thermoplastic matrix fibers. The finenesses of the yarns of 400 tex and 800 tex were achieved. In addition, ring spinning was successfully used to produce yarns with a fineness of approx. 100 tex from the off-cuts rCF. The microsections of the yarns are shown in figure 1.  Spinning by means of rotor spinning was found to be not possible due to increased fiber damage. The self-constructed hollow spindle spinner could not be used due to insufficient control technology.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen | Figure 1: Micrograph of the rCF hybrid yarns from ring (top) and friction (bottom) spinning

Considering both friction and ring spinning the produced yarns showed a high level of unevenness. During the different processing stages of carding, drawing and spinning up to the yarn, a significant fiber length reduction (e.g. arithmetic mean value over 50 %) could be observed concerning all rCF source materials, such as pyrolysed and cut fibers. In addition, a doubling of the short fiber content (shorter than 12 mm) due to the ring spinning process has been monitored. Nevertheless, the yarn strength was sufficient for further processing to UD Composite plate by means of wrapping and consolidation by hot pressing. The testing of the mechanical properties of the test plates is still ongoing. The semi-finished products of the production steps are shown in figure 2.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen | Figure 2: Processing steps of fiber recycling of carbon fibers from fiber flock to the rCFRP

Acknowledgement

The research project 19814 N of AiF Projekt GmbH, Berlin is funded by the Federal Ministry of Economics and Energy within the framework of the Forschungskuratoriums Textil e.V. on the basis of a decision of the German Bundestag.

Contact

Erik Bell

Portrait AZL NeswLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80-23446
Mail: erikgordon.bell@ita.rwth-aachen.de

Stephan Baz

Portrait AZL NeswLIGHT

Head of staple fiber technologies
Deutsche Institute für Textil- und Faserforschung Denkendorf
Phone: +49 (0)7 11 / 93 40 – 252
Mail: stephan.baz@ditf.de

Georg Stegschuster

Portrait AZL NeswLIGHT

Research Assistant
Institut für Textiltechnik Augsburg gemeinnützige GmbH
Phone: +49 821 8090 3413
Mail: georg.stegschuster@ita-augsburg.de

 

ITA Acquires High-Performance Warp-Knitting Machine for Semi-Finished Fibre Products –
“BIAXTRONIC CO” – from Karl Mayer

ITA Acquires High-Performance Warp-Knitting Machine for Semi-Finished Fibre Products – “BIAXTRONIC CO” – from Karl Mayer

The Institut für Textiltechnik (ITA) of RWTH Aachen University, one of the most renowned institutes worldwide in the field of textile technology has procured a high-performance warp-knitting machine with course-oriented weft-insertion system (BIAXTRONIC CO) from Karl Mayer for the development of knitted open-meshed textile grids and non-crimp fabric structures for the fibre composite sector.

Technical textiles play a central role in all areas and application fields of ITA. The ITA Construction Composites research group as part of the Collaborative Research Centre 532 developed textile reinforcement structures for concrete matrices with the help of the current in-house machine (Karl Mayer Malimo) over the years 1999 to 2011. With the procurement of the BIAXTRONIC CO further development and production of reinforcement structures for concrete matrices is foreseen. Furthermore, the new machine will also be used for the development of functional samples/prototypes in other application fields such as:

  • Production of hybrid knitted fabric structures over a non-woven substrate
  • Reinforcement of wound dressings in the medical textiles sector
  • Manufacture of unidirectional (UD) fabrics for fibre-reinforced plastics and plain knitted fabrics for thermal textiles in the mobility sector

The new machine platform comes with new features which open up new research avenues for ITA and its research partners (as depicted in figure 1).

 

AZL Partner ITA of RWTH Aachen

© KARL MAYER | Figur 1: BIAXTRONIC and new research opportunities

The possibility to feed in base substrate will allow ITA to fundamentally research applications in the field of geotextiles. The machine includes the Karl Mayer Command System “KAMCOS” with an ethernet interface for integration into an existing network, which fulfils the requirements for research topics in the field of Industry 4.0, inline quality control, sociology, networking of the process chain etc. The newly developed electronic guide bar control system and the possibility to vary process parameter inline will improve the product quality substantially and help in producing locally adapted tailored textiles.

ITA thrives on the development of new innovative technologies and products, which mainly result from bilateral research projects between industry and universities. Thus, with the acquisition of the BIAXTRONIC CO ITA is looking forward to undertake collaborative projects with national and international partners in the coming years. ITA plans to unveil the BIAXTRONIC CO on 21st January 2021 (save the date!) and cordially invites interested partners to attend the one-day industry event in Aachen.

This acquisition of the BIAXTRONIC CO is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) and the state of North Rhine-Westphalia, project number INST 222/1264-1 FUGG. ITA extends its gratitude towards the DFG and the state of North Rhine-Westphalia for their financial support.

Contact

Shantanu Bhat

Portrait AZL NeswLIGHT

Research Associate
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80-24741
Mail: shantanu.bhat@ita.rwth-aachen.de

 

Natural fiber-reinforced composites for structural applications based on novel zero twisted bast
fiber yarns

Natural fiber-reinforced composites for structural applications based on novel zero twisted bast fiber yarns

Novel, zero-twist yarn structure of flax and hemp  with staple lengths of approximately 100 mm  for use in natural fiber-reinforced plastics (NFRP) for (semi-) structural components

Due to growing environmental awareness in society and increasing sustainability requirements for products and manufacturing processes by government institutions, new types of processes and products are needed. Resource and energy-efficient use of raw materials, as well as production and construction methods are of central importance in this context. Natural fiber-reinforced plastics (NFRP) show a unique range of properties: low CO2 emissions during production, good damping properties, low tendency to splinter in case of failure, particularly high stiffness-related lightweight potential under bending loads and good recyclability. NFRP with good mechanical properties are currently produced from long flax yarns with long fiber bundles obtained from traditional flax processing, which are of very high quality, which is reflected in a high price.

In order to enter market segments with greater price pressure, such as vehicle manufacturing, sports equipment or construction materials, the price of a natural fiber yarn must be reduced significantly.

In the present project (NF-CompPlus) a novel, zero-twist yarn structure of bast fiber bundles with staple lengths of approximately 100 mm (hemp from the disordered line or flax tow from the traditional longitudinal line) for use in natural fibere-reinforced plastics for (semi-) structural components has been developed. The new zero-twist yarn structure based on shorter and less expensive bast fibere bundles offers the potential to overcome the problems mentioned above. The mechanical properties of the newly developed composites are similar to the mechanical properties of composites made from a long flax roving available at the market (see Figure 1). The advantages of low raw material costs and suitable mechanical properties make renewable materials also attractive for new fields of application. A further cost reduction would result from the use of cheaper hemp from the disordered line (total fiber line). The new yarns are directly used to produce unidirectional composites by winding or pultrusion or are further processed to unidirectional fabrics which are further processed to composite materials, e.g. by vacuum infusion or a transfer moulding.

In the project, the entire textile process chain is examined, from fiber extraction and preparation, textile manufacturing to the production of NFRP (see Figure 1). A first demonstrator for a leaf spring of a bogie of a narrow-gauge railroad has already been manufactured via vacuum infusion.

AZL Partner ITA of RWTH Aachen

© HSB – Hochschule Bremen, City University of Applied Sciencses, The Biological Materials Group | Figure 1: Process chain for the development of composites from alternative non-twisted staple fiber yarns and unidirectional (UD) fabrics with different processing techniques and mechanical characteristics of composites reinforced with flax (red and yellow ellipses in the diagram) and hemp (green circle in the diagram) compared to commercially available flax-fiber-reinforced composites.

Acknowledgement

The research project was carried out in the framework of the industrial collective research programme. It was supported by the Federal Ministry of Food and Agriculture (BMEL) on the basis of a resolution of the German Bundestag (funding no. 22026215, 22014817 &  22015417). As well we want to thank our project partners for the good cooperation.

Partners:

  • HSB – Hochschule Bremen, City University of Applied Sciences
  • INVENT GmbH
  • Wenzel & Hoos GmbH
  • SachsenLeinen GmbH
  • BAFA Neu GmbH
  • Novacom GmbH
  • nova-Institut GmbH
  • Institut für Textiltechnik (ITA) of RWTH Aachen University

Contact

Erik Bell

Portrait AZL NeswLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80-23446
Mail: erikgordon.bell@ita.rwth-aachen.de

Dr.-Ing. Nina Graupner

Portrait AZL NewsLIGHT

Research Assistant
Hochschule Bremen, City University of Applied Sciences
Fakultät 5, Abtl. 2, Bionik: AG Biologische Werkstoffe
Phone: +49 421 5905-2719
Mail: nina.graupner@hs-bremen.de

 

Microwave technology in coating processes

Microwave technology in coating processes

Producing semi-finished materials for textile fiber composite components faster and more energy- and resource-efficient

Thermoplastic organo sheets and tapes are experiencing high market grow rates. Beside melt impregnation or film stacking the use of solvent impregnation is a suitable technique aiming for best impregnation results. The costs for a coating plant for solvent-based thermoplastic impregnation for composite production, are approx. 30% allotted to the drying section. The main part of the variable costs of the production process is energy input and auxiliaries. The production speed of such a plant is mainly determined by the required residence time of the impregnated semi-finished product during evaporation of the solvent in the convection oven.

AZL Partner ITA of RWTH Aachen

© Jakob Weiß & Söhne Maschinenfabrik GmbH 

In the project “MicroCoat”, a novel process chain for the production of thermoplastic impregnated semi-finished products is being developed. The innovation consists of applying microwave technology to improve the distribution of matrix material in the fabric and for drying, as well as in the simultaneous application of surface pressure on the semi-finished product. This means that the semi-finished fiber composite product is simultaneously consolidated (solidified) during the drying process. This enables the production speed to be increased by 20 %, with a simultaneous reduction in production costs of 10 % in relation to the total product, as well as a reduction in energy consumption of 30 % compared to machine setups relying on melt impregnation and a double belt press.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen 

With microwave drying, the heat can be applied homogeneously, with the semi-finished product being dried from the inside. Microwave drying is equipped with a press for consolidation and also has an extraction and recycling system for the solvent that evaporates during the drying process. The implementation is to take place in the form of modular components to be developed, to also enable the retrofitting of existing production plants.

Acknowledgement

The ITA would like to thank the Federal Ministry of Education and research for its support in the project MicroCoat. We also want to thank our project partners Fricke und Mallah Microwave Technology and Jakob Weiß & Söhne Maschinenfabrik for the good collaboration.

Contact

Andreas Bündgens

Portrait AZL NewsLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80-23260
Mail: andreas.buendgens@ita.rwth-aachen.de

 

Design and Manufacture of Multifilament-Wound Composite Pressure Vessels for Hydrogen Storage

Design and Manufacture of Multifilament-Wound Composite Pressure Vessels for Hydrogen Storage

Hydrogen fuel cells enable promising opportunities in terms of emission-free mobility. ITA designed and manufactured multifilament-wound composite pressure vessels for mobile applications. Therefore, carbon fiber towpregs rovings were processed in order to increase winding speeds.

The reduction of greenhouse gases towards an emission-free mobility is the most important goal of future automotive concepts. In this field, hydrogen fuel cells enable promising opportunities in the transport sector. By means of obtaining hydrogen from renewable energies such as wind or solar power, the emission of greenhouse gases can be completely omitted. Since fuel cell-powered vehicles are more cost-intensive compared to electric vehicles, the main cost drivers, e.g. fuel cell and hydrogen storage systems, are of major research interests for affordable solutions. For hydrogen storage in fuel cell-powered vehicles, composite pressure vessels (CPV) are typically operated at 700 bars. These type IV vessels, consist of an inner plastic liner, metallic bosses and a surrounding carbon fiber reinforced plastic (CFRP).

In collaboration with the industry, the Institute for Textile Technology (ITA) of RWTH Aachen University, Germany, developed type IV pressure vessels for automotive applications in two iterative steps. In a first step, a concept for joining the bosses and liner was developed. Thereafter, simulations for a suitable dome shape and laminate design were conducted. The designed pressure vessels consist of a three-liter high-density polyethylene liner, stainless steel bosses and a surrounding carbon fiber reinforced epoxy laminate. For the manufacturing of the pressure vessels, the multi-filament-winding (MFW) technology was used. Due to the processing of up to 48 of rovings simultaneously in MFW, the productivity can be increased drastically. Further, the MFW process is especially suited for the processing of pre-impregnated fibers, also referred to as towpregs, which allows elevated winding speeds and the skipping of an in-process impregnation. In this regard, a 1.600 tex carbon fiber towpregs with a resin content of 70 weight percent were processed. After curing, two CPV were subjected to a burst test and the results were compared to the finite-element analysis.

The second iterative step covers the further development of the CPV. Therefore, the current design will be adapted in terms of boss design and laminate lay-up considering the burst test results. These CPV will be subjected to further burst tests for the validation and further development steps.

AZL Partner ITA of RWTH Aachen University

© ITA of RWTH Aachen

Contact

Tim Mölling

Portrait AZL NewsLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23450
Mail: tim.moelling@ita.rwth-aachen.de

 

Tailored Fiber Placement and prepreg technology combined in one process

Tailored Fiber Placement and prepreg technology combined in one process

More than 120 manufacturing SME in Germany use Tailored Fiber Placement (TFP) technology, either for semi-finished products or component manufacturing. TFP technology allows reinforcementfibres to be placed in the correct load path with near to zero cutting waste. This results in optimum material utilization and thus a reduction in weight. For thermoset products, a combination of TFP structures e.g. a TFP drilling hole reinforcement, and a flat textile product such as fabric is currently possible only with dry textiles. For pre-impregnated textiles (prepregs), there is no possibility to combine prepregs with TFP yet. Prepregs are used particularly in the area of high-performance components, where exact fibre placement and optimal fibre-matrix ratios has to meet the highest quality requirements. Prepregs popular in the industry and, with a share of 45 % (41,200 t in 2015), they are the most widespread manufacturing process for carbon fibre composite materials.

In the research project “FreePreg”, a process chain is being developed, which enables continuous production of pre-impregnated high-performance FRP structures with load-bearing continuous filaments on a carbon fleece. By means of Tailored Fiber Placement (TFP), carbon fibre rovings are stitched along the load paths onto a carbon fleece. As a functional embroidery ground, the carbon fleece improves the impregnability and mechanical properties of the component to be produced. Several TFP structures are applied next to each other step by step, making optimum use of the web width. The embroidered nonwoven webs are then joined together to form a continuous roll of fabric and, in a continuous process, are deposited in a pre-produced resin film and pre-impregnated on the top side. The productsare freely positioned, already pre-impregnated preforms on a roll- so-called FreePregs. Those FreePregs can either be used for component production without the need of additional resin infusion or can also be combined with traditional prepreg processing as prepreg-compatible reinforcement structures. . In addition, the semi-finished product can be processed with classic prepregs. A comparison of the existing and the new process chain is shown in figure.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen | Figure: Comparison of the existing and the new process chain 

Acknowledgement

We would like to thank the Federal Ministry of Economics and Energy (BMWi) for funding the research project within the framework of the Industrial Joint Research (IGF) of the AiF Research Network for Small and Medium-Sized Enterprises.

Contact

Andreas Bündgens

Portrait AZL NewsLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80-23260
Mail: andreas.buendgens@ita.rwth-aachen.de

Waldemar Biche

Portrait NewsLIGHT

Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80-24711
Mail: waldemar.biche@ita.rwth-aachen.de

Lennart Jacobsen

Portrait AZL NewsLIGHT

Head of Hybrid Materials and Impregnation Technologies (HIT)
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49/(0) 241 80-23282
Mail: lennart.jacobsen@ita.rwth-aachen.de

 

Composite rocket - Innovative lightweight technology enables fiber reinforced composites to lift off
into space

Composite rocket – Innovative lightweight technology enables fiber reinforced composites to lift off into space

Researchers and students at the ITA Aachen design and develop a full composite rocket body tube and detachable fins using innovative technologies, multi-supply filament winding and Tailored Fiber Placement.

Lighter the weight of the propulsion system, higher the payload mass the rocket can transport. One of the major weight contributors is the body tube. The body tube is required to provide a structure and also house the engine mounts. Fins are attached to the body tube to provide stability to the rocket and to prevent wobbling or tumbling of the rocket during flight. In this case, we consider the design and development of a mid-range competition rocket (total length: ca. 3 meters) of the SpaceTeam Aachen.  The embodiment design of the rocket is shown in Figure 1.

AZL Partner ITA of RWTH Aachen

© SpaceTeam Aachen | Figure 1: Embodiment design of the lower body tube and fin connection

Carbon Fiber Reinforced Polymers (CFRP) are established materials which are commonly used where high strength to weight ratio is required. While many technologies are available for manufacturing CFRP parts, filament winding stands-out for rotational symmetric parts like the body tube. It is a simple process where fibers are placed (wound) on a rotating mandrel where wet winding is the most common technique used today.

Space application mostly demands high quality products rather than rapid production. This in view, hybrid fibers, hence known as TowPregs, offer an elegant solution. TowPregs are resin pre-impregnated fibers which offer certain advantages over wet-winding process. For example, uniform impregnation and higher accuracy in fiber volume fraction, which are vital to ensure high quality products. The body tubes are wound using carbon fibre TowPregs and nose cone using gass fibre TowPregs which were developed at F. A. Kümpers GmbH & Co. KG, Rheine (GER).

AZL PArtner ITA of RWTH Aachen

© ITA of RWTH Aachen | Figure 2: Body tube with fins and nose cone manufactured using Tailored Fiber Placement and Filament Winding.

One of the many challenges, a competition rocket face, is the fin. Conventionally, these thin fins (thickness ca. 2 mm) are connected using permanent joining technique (adhesives). Small damages to the fin demand the need to change the complete lower body tube. At ITA, a concept for a detachable fin was developed. Fins were manufactured using Tailored Fiber Placement (TFP) in which inserts were integrated into the fin structure during the preforming process. These inserts were then used to connect the fins to the body tube. TowPregs were also employed for TFP process which reduced the complex vacuum infusion or consolidation process. TFP offers near-net shape manufacturing with almost no material wastage. Along with fixing, the stitching yarns enhance the delamination resistance of the component. The model rocket consists of carbon fiber body tubes with three fins attached using inserts from KVT-Fastening GmbH, Illerrieden (GER), and a glass fiber nose cone as shown in the Figure 2.

Additional information can be found at www.spaceteamaachen.de.

Contact

Kumar Jois

AZL Portrait NeswLIGHT

Researcher “Tubular Composite Reinforcements”
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 49126
Mail: kumar.jois@ita.rwth-aachen.de

Max Schwab

AZL Portrait NewsLIGHT

Researcher “Automated Composite Production”
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23473
Mail: max.schwab@ita.rwth-aachen.de

Multiaxial woven fabrics based on novel weaving technology

Multiaxial woven fabrics based on novel weaving technology

Recently finished research project on weaving of multiaxial fabrics demonstrates suitability of open-reed-weaving technology for production of low waste laminates

In the project Woven-plusX (funded by German Federal Ministry of Education and Research, funding code: 20148 N), woven multiaxial semi-finished products for fiber composite applications were developed and characterized using open reed weaving processes. First of all, process limits of the weaving technique were determined with regard to the patterning possibilities in open reed weaving. The results are available in the form of technology cards and provide a comprehensive overview of the production-related boundary conditions and serve as a basis for future weaving developments. On the basis of three patterning approaches for fabric weaving, three semi-finished products were first theoretically designed, the binding was developed and subsequently implemented in terms of weaving technology. The produced fabrics were mechanically characterized. Tensile strength and stiffness were found to be similar to those of conventional semi-finished products. The knowledge gained with regard to the development of the weave was transferred into a guideline for weave design and programming. Potential fields of application for multiaxial fabrics were identified and compared with conventional fabrics in the course of an economic evaluation. The process offers specific cost advantages, especially for components with large surface areas. One potential application is plates or panels manufactured in a coating process with integrated reinforcement in up to four load directions.

AZL Partner ITA of RWTH Aachen

© ITA of RWTH Aachen University 

Contact

Yanick Schlesinger

Portrait AZL NewsLIGHT

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23457
Mail: yanick.schlesinger@ita.rwth-aachen.de

 

New Collaborative Research Center/Transregio on Carbon Reinforced Concrete started

New Collaborative Research Center/Transregio on Carbon Reinforced Concrete started

Novel approaches to design and construction of carbon fiber reinforced concrete are developed within the new DFG-funded Collaborative Research Center/Transregio 280 “Design Strategies for Material-Minimized Carbon Reinforced Concrete Structures – Principles of a New Approach to Construction”.

The Technische Universität Dresden and the RWTH Aachen University are collaborating within the DFG-funded Collaborative Research Center/Transregio 280 “Design Strategies for Material-Minimized Carbon Reinforced Concrete Structures – Principles of a New Approach to Construction”, aiming to develop the design and construction methods of the future construction industry.

Textile reinforced concrete (TRC) enables new design and construction possibilities for the construction industry, since the high performance textiles used as reinforcement do not rust and therefore only need minimal concrete cover. TRC has been investigated since the late 1990s and is currently entering the market. Elements with a thickness of only 15 mm are already possible today, as shown in the picture.

However, current applications do not use TRC to its full potential. The textile reinforcement is used as a “drop-in” alternative to the steel reinforcement it substitutes and the production processes are not changed much. While this approach already offers various advantages, new and alternative production processes such as 3D concrete printing and extrusion synergize even better with the flexibility reinforcement textiles offer.

The aim of the Collaborative Research Center is to completely rethink the design and construction process in the construction industry, tailoring it for use of TRC and unlocking the full potential of this material class. In addition to adapting the construction processes, new inspirations for designing are taken from biology, mathematics and art.

Within that framework, the ITA develops new, tailored coating solutions that allow for curing of the coated reinforcement textile during the concrete production process. This leads to greater flexibility of the textile during preparation and processing with very high mechanical performance in the finished component. Approaches to be investigated for this tailored curing are established methods like heat and UV-radiation as well as new methods like the alkalinity of the concrete, microwaves or induction.

The DFG awarded the research grant based on the many years of experience of both universities in the area of TRC, with a total of 19 individual institutes participating in the research project.

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© ITA of RWTH Aachen University | One current application of carbon reinforced concrete: slender roof elements at ITA

Contact

Martin Scheurer

Portrait NewsLIGHT

Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23471
Mail: martin.scheurer@ita.rwth-aachen.de