List of Poster-Abstracts

Transcription

1 List of Poster-s K1 Making use of particle foam technology for the production of textile preforms Schöfer, Sven Mack, Christoph; Basler, Aaron; Gries, Thomas Fibre-reinforced plastics (FRP) are of growing importance in the industry due to their mechanical properties and light weight. However, a widespread use is prevented by high manufacturing costs, lack of process automation as well as limited recyclability. Based on the deficits described above, the use of particle foams to manufacture, process and handle textile preforms is investigated within the collaboration project AutoPreFoams. The objective of this project is to manufacture complex 3D-preforms at low processing times, both textile and load conform, while reducing scrap rates from draping errors and offcut. The new approach is a single-layer-specific forming of layer stacks by a particle foam expansion. The method towards achieving this goal is a single-layer specific forming of, stitched together, stacks by particle foam expansion in a moulding machine. 3D-preforms of higher quality, less cutting waste and the reduced number of tool changes will be the main advantages of this new technology. K2 Laser processing of preforms and fastener integration for multi material design applications Oppitz, Sebastian (Sebastian.Oppitz@ita.rwth-aachen); Janssen, Stefan; Gries, Thomas Current state of the art lightweight strategies are using hybrid constructions of metal- and composite-materials, especially Fiber Reinforced Plastics (FRP). Economically and technically advantageous processes for the integration of fasteners in FRP provide the basis for the substitution of commercial parts by beneficial composite elements. Objectives of the research project LaserInsert are to increase required pull-out forces of fasteners for composites and to reduce the amount of process steps and time for an application of fasteners. The approach is the development of a beneficial process to integrate metal fasteners in textile preforms. The textile preforms are drilled by using ultra-short pulsed laser radiation. Laser drilling of CFRP-preforms offers the possibility to economically manufacture notches into the unconsolidated textile. The highly precise notches are used for fastener integration. Due to the innovative process chain, increased pull-out forces, less process steps and reduced process times can be realized. 1

2 K3 Highly Productive Joining Techniques for Composite Parts using Tufting Technology Wiche, Marius Gries, Thomas For the production of composite parts using liquid composite moulding technologies, near net-shape preforms are required. These preforms are produced by a multi stage process by combining sub-preforms, which have to be joined in order to facilitate load transmission. This joining can be done by sewing technologies, such as tufting. By using tufting, material accumulation is avoided resulting in a significant reduction of manufacturing and material costs. As today, commercially available tufting technologies operate with speeds up to 300 Stitches/Minute. Due to the fixation of the yarn by friction, looping is uncertain with higher speeds thus resulting in inconsistent seam quality. In order to improve the process efficiency new tufting technologies with higher sewing speeds and ensured looping are required. In a collaborative research project, Institut für Textiltechnik of RWTH Aachen University and EFAB GmbH have developed a new tufting technology with speeds up to 1000 stitches per minute. K4 Potential of Controlling the Fiber Orientation in a Braiding Process Reimer, Viktor (Viktor.Reimer@ita.rwth-aachen.de); Gries, Thomas Radial over-braiding is used to produce preforms in one step made of e.g. carbon and glass, fibers for e.g. airspace and automobile industry. One of the most important quality criterions of the braiding process is the fiber orientation, known as braiding angle. The setup time of the braiding angle can take depending on preform complexity long time and much effort. There are no sufficient empirical or theoretical models to describe dependencies of process outputs and parameters. The objective is to develop a braiding angle feedback control system for the braiding process by deducing a differential equation for braiding angle, creation of simulations based on this equation and estimation of the feedback control parameters. First results show the potential of controlling the braiding angle. The braiding angle can be adjusted and controlled with very low angle deviations with low effort. K5 Ultra low-weight hollow carbon fibres Pursche, Franz (Franz.Pursche@ita.rwth-aachen.de); Brüll, Robert; Langgartner, Janis; Seide, Gunnar; Gries, Thomas The main goal of this research work is the development of ultra-low weight hollow carbon fibres. These fibres can be produced quicker than standard carbon fibres and have a reduced weight with comparable mechanical properties. These effects result in a minimized thermoplastic CFRP weight and increase the total cost efficiency. This research shows the production process of hollow carbon fibres in lab-scale. The focus lies on the stabilization and carbonization process. For the stabilization and carbonization process parameters are developed, by which the hollow structure of the fibres is maintained. SEM microscopy is used to measure the change of surface properties during stabilization and carbonization. FTIR and DSC are used for further analytics of the stabilization process. The stabilization and carbonization process of the hollow carbon fibres is compared to the stabilization and carbonization of conventional carbon fibres. The final product is a carbonized fibre with a hollow cross section. 2

3 K6 Adjustment of the mechanical properties of carbon fibres during carbonization Pursche, Franz Burscheidt, Pia; Seide, Gunnar; Gries, Thomas One crucial production step during carbon fibre production is the process of carbonization. The mechanical properties (strength, young s modulus and breaking elongation) of the produced carbon fibres are adjusted in this process step. However, the cause-effect relationships of the different process parameters (e.g. temperature, residence time, fibre tension) are still not fully understood. Therefore the main aim of this research is the investigation of the influence of the process parameters temperature and residence time during carbonization on the mechanical properties of the produced carbon fibres. Final goal is the development of process parameters, by which the mechanical properties of produced carbon fibres can be adjusted. Furthermore, carbon fibre strength and young s modulus are maximized. K7 Fiber reinforced thermoplastic composites - Technologies along the process chain Robert, Brüll (Robert.Bruell@ita.rwth-aachen.de); Köhler, Thomas; Röding, Tim; Vonberg, Klaus; Seide, Gunnar; Gries, Thomas Fiber reinforced composites offer great potential besides traditional lightweight metal materials such as aluminum. The department Yarn Structures and Composites (YSC) is conducting research on yarn based fiber reinforced thermoplastic composites and their use in a variety of applications. The advantages of thermoplastic composites are manifold. In addition to high strength, rigidity and low mass, they provide a better recyclability compared to thermoset composites due to their hot formability. Moreover, the use of various textile structures and the hot formability of organic sheets open up a broad field of applications for fiber reinforced thermoplastics. Especially the yarn based approach allows new material combinations between matrix fibers and reinforcement fibers. This poster publication focuses on the current research opportunities for yarn structures and composites concerning the processing of carbon fibers to thermoplastic composites. K8 Usage of In-situ-polymerization for carbon fibre reinforced semi-finished parts with thermoplastic matrix Röding, Tim (Tim.Röding@ita.rwth-aachen.de); Akdere, Musa; Gries, Thomas Lightweight design has gained more and more relevance over the last decades. Especially in automotive industry it is of paramount importance to reduce weight and save fuel. At the same time the demand for safety and performance increase the components weight. To reach a trade-off driving comfort and efficiency new lightweight materials have to be developed. One possible way to reach this is the usage of carbon fibre reinforced thermoplastics (CFRTP) as a lightweight substitute material. In contrast to conventional carbon fibre reinforced plastics (CFRP), CFRTPs are cheaper and have better properties in shock resistance, hot forming ability, weldability and recyclability. However, the impregnation of the textile requires high pressure, because of the high viscosity of the melted polymer. A new innovative approach for CFRTP is the usage of in-situ-polymerization with ϵ- caprolactam as matrix, which has a much lower viscosity and thus requires much lower pressure for impregnation and consolidation. 3

4 K9 Innovative Multi Filament Winding Technique Münch, Pia Lengersdorf, Michael; Gries, Thomas Hydrogen stored in pressure vessels is a promising alternative in the course of the energy revolution and an advance in automotive electrification. Fibre-reinforced plastics (FRP) are well known for their weight-related characteristics and thus highly suitable for this application. But the wet winding process currently used for the manufacture of pressure vessels does not fit the requirements for a series production. A new multi filament winding technique, which combines the high speeds of the braiding with the mechanical properties of the winding process, offers an alternative. The technology MFW-48 processes up to 48 fibres simultaneously, while a mandrel rotates and moves back and forth horizontally. The reinforcing fibres, e.g. carbon, are positioned on the mandrel successively. This results in a unidirectional and non-crimped structure, which increases mechanical properties in fibre direction. Additionally, a complete layer is placed down on the mandrel within just one step. K10 Tailored NCF Happach, Wilko (Wilko.Happach@ita.rwth-aachen.de); Gries, Thomas The so called Tailored NCF -technology which is currently being developed at ITA, enables a one-step production of non-crimp fabrics (NCF) with integrated reinforcement structures according to load paths in the final part. The reinforcements (e.g. patches, stringers) are automatically placed on the fabric before being fixed to the underlying NCF by the knitting module. Afterwards the reinforced NCF is cut on the machine into the desired shape, thus eliminating the conventional and costly preforming process consisting of manual layup. The technology consists of a modified NCF production machine (LIBA Copcentra MAX 3 CNC) with added portal robots for placement of reinforcement structures, a camera system to verify the positions of placed structures, a segmented and movable needle row in the knitting module as well as an automated cutting module. K11 Spreading of high modulus fibers Happach, Wilko (Wilko.Happach@ita.rwth-aachen.de); Gries, Thomas The modular spreading test stand at ITA can be used as a complete development environment to test different spreading processes and different fiber materials ranging from conventional carbon or glass fibers to specific customer demands. The spreading results are measured online by optical sensors as well as by fiber breakage and tension sensors. Within the current AiF-project AutoTow, an automated control of the bar spreading process is being developed. The active control of the spreading process is obtained by detecting the initial and spread fiber tow properties and adjusting the influencing factors friction and the wrapping angle of the tow and the spreading bar. The friction is adjusted by changing the rotational speed of the bars while the bar wrapping angle is adjusted by changing the vertical position of the spreading bars. The outcome is a spread fiber tow with a constant width over time. 4

5 K12 Integral reinforced fabrics - Advanced reinforcement textiles for composites Lenz, Christopher (Christopher.lenz@ita.rwth-aachen.de); Gries, Thomas Complex load cases and geometrical requirements often demand several local reinforcements within the part or an increase of the part thickness. This leads to complex production processes or a higher part weights. One promising approach to solve this dilemma is the application of tailored textiles with integrated reinforcements. Such production technologies allow a single-step production of integral reinforced textiles. The main limitation towards an industrial application is the missing experience and knowledge regarding product design and evaluation tools. At ITA a modified product creation process for the utilization of tailored textiles in composite parts was developed. General approach is to integrate the tailored textiles based concept as subpreform in the conventional product development process. For the single steps within the concept suitable methods were chosen or developed. The whole concept was then validated with a demonstrator part. K13 Recycled carbon fibre reinforced thermoplastic composites Köhler, Thomas (Thomas.köhler@ita.rwth-aachen.de); Bürke, Melanie; Lütke, Claus; Gries, Thomas; Seide, Gunnar Carbon fibre reinforced composites have become a technical necessity in large sectors of the industry. Therefore, the development of technologies to process recycled carbon fibres becomes increasingly important. Recycled carbon fibres can be used to produce a nonwoven to reinforce a thermoset matrix system. An alternative to thermoset composites are thermoplastic composites. The advantages of thermoplastic composites are shorter cycle times and higher impact resistance. The viscosity of molten thermoplastic material is distinctly higher than the viscosity of duroplastic material. In order to reduce the melt flow pahts, the reinforcing fibres are being mixed with thermoplastic matrix fibres to produce a nonwoven. This nonwoven is heated and consolidated to produce a composite. The cycle time of this process is determined by the heating and cooling of the material. The aim is to reduce the cycle time in order to make the production more economical. 5

6 K14 Fibre characteristics of polyacrylonitrile based carbon fibre precursors Peterek, Stefan Gries, Thomas; Seide, Gunnar The following tests have been performed. To make the characteristics and structural properties of carbon fiber precursors obvious, we compare them with textile PAN fibers. WAXD (orientation and crystallinity of the structure) Gas pycnometie (density) SEM (homogeneity and roundness of the fibers, fibre structure) FAVIMAT (Residual strain and homogeneity of fiber) DSC (oxidation and dehydration peaks during thermal conversion) The microstructure of the fibres is revealed and it is shown how the microstructure is influenced by the choice of process parameters. The reader gets an impression of the wet spinning process, the intended microstructure of precursor fibres and appropriate process conditions. The Institute of Textile Technology at RWTH Aachen University has wet spinning lines in different scales (Lab scale, technical scale and industrial scale). In the year 2014 we have started up the industrial scale carbon fibre line. Worldwide, only 3-4 Institutes are doing comparable research activities and have access to comparable research facilities. K15 Adjustment of the mechanical properties of carbon fibres during carbonization Pursche, Franz Biche, Waldemar; Gries, Thomas; Seide, Gunnar Because of their outstanding mechanical properties combined with low density carbon fibres are in the last years increasingly used for light-weight applications in the transport or the energy industry. However, due to their energy demanding production process carbon fibres are still not used for mass applications (e.g. automotive industry) because of their high price (15 25 /kg). One bottleneck in the thermal conversion of polyacrylonitrile (PAN) based precursors to carbon fibres is the process step of stabilization. Stabilization requires temperatures up to 300 C and process times up to 120 minutes. Nearly 50 % of total conversion costs are accounted by stabilization. The approach of this research work is the reduction of stabilization times in order to minimize the total production costs of carbon fibres. As a result, the total stabilization time is reduced to 26 minutes while maintaining the mechanical properties comparable to a Toho Tenax HTS40 carbon fibre. 6

7 K16 Energy and Carbon Dioxide Emission Savings Potential of the Use of Carbon Fibre Reinforced Thermoplastics in Automotive Applications Röding, Tim Gries, Thomas; Seide, Gunnar In recent years lightweight design has become of paramount importance in the automotive industry. On the one hand, new laws and carbon emission regulations encourage manufacturers to develop vehicles which consume less fuel and emit less greenhouse gases. On the other hand, the vehicle weight increases due to more powerful engines, luxury interior or alternative propulsion systems. Since carbon fibre reinforced plastics (CFRPs) are lightweight and strong at the same time, they are suitable as an effective means of reducing car weight. Compared to conventional CFRPs with a thermoset matrix, carbon fibre reinforced thermoplastics (CFRTPs) can be produced faster and cheaper, are easier to recycle and weldable. Weight reductions arising from the use of CFRTPs might lead to significant energy savings in the use phase, which accounts for the biggest amount of energy consumption in the automotive life cycle. Hence, this study compares the energy consumption for the manufacturing process with the energy savings in the car s utilization phase. The break-even points in terms of energy and CO2 emissions of the CFRTP parts are determined. K17 Low-cost carbon: Polyethylene as a suitable material for carbon fibre manufacture De Palmenaer, Andreas (Andreas.Depalmenaer@ita.rwth-aachen.de); Wortberg, Gisa; Gries, Thomas Carbon fibre impresses with its excellent mechanical properties and low density. Due to the complex production process, production costs (15 25 /kg) are high and carbon fibre is not appropriate for mass usage in the automotive or energy sector (renewable energy) so far. The main cost factor (50 % to 65 % of the carbon fibre production costs) is the production of the polyacrylonitrile (PAN) precursor. These high costs mainly arise because of the complex solvent spinning procedure, the solvent s preparation and PAN s high commodity price (2 5 /kg). Alternative polyolefin based precursors are a possibility to reduce costs for the carbon fibre production. Especially polyethylene (PE) is, due to its high availability, the low material price (1 1.5 /kg) and the good suitability as precursor, a promising material. Furthermore, the production costs could be reduced as a melt spinning process is used to produce the PE-precursor instead of a solvent spinning process to produce the PAN-precursor. Since the complex and cost-effective solvent s preparation does not apply, melt spinning is faster (up to 2,500 m/min), more energy efficient and more environmentally friendly. 7

8 K18 Surface characteristics of yarn guiding elements and their influence on the behavior of carbon fibre processing Beck, Tobias Papenbreer, Lisa; Gries, Thomas Carbon fibres show high strength in filament direction, whereas they are brittle perpendicular to the filament direction. Filament breakages are caused due to the contact between yarn and yarn guiding elements. The filament breakages are caused by inappropriate surface properties of the yarn guiding elements. Today polished and chrome-plated surfaces are used for yarn guiding elements. The Aim of the researches are decreasing the filament damage by 20 % comparing to conventional surfaces by using structural chrome surfaces and decreasing the coefficient of friction by at least 30 %. To reach this, an identification of surface criteria independent from roughness depth and the consideration of topography type is necessary. The second step is the characterization of structure layers in classes and creating and validating of an evaluation method. The investigations showed that a rougher surface like the Topocrom structure decreases the upcoming friction by 35 %. K19 Innovation actions in Textile Construction at ITA Koch, Andreas (Andeas.Koch@ita.rwth-aachen.de); Quadflieg, Till; Plümpe, Magdalena; Dittel, Gözdem; Gries, Thomas; Jockenhövel, Stefan The use of technical textiles in construction gets more and more important due to the goals of sustainability. Textile reinforced concrete (TRC) is one of the most impressive examples for an innovative composite material, which reduces the CO 2 -emmissions significantly by reduction of the cement consumption compared to steel reinforced concrete. Textile reinforcements made of AR-Glass or carbon fibres are not corrosive and enable very thin concrete constructions (10 mm < x < 80 mm). A holistic view of composites in construction will be created within the public-funded project VERBUND.NRW. 11 institutes of RWTH Aachen & FH Münster will analyze the current use of composites in construction along the entire value chain. The main objective is the improvement of the resource efficiency through recycling-appropriate use of composites in construction. ITA will present the actual innovation actions for both research topics and its research competences. 8