All ITA news at a glance | NewsLIGHT #14 | ITA

Find all ITA news here:

CompositesReloaded status update - Collaborative production scenarios for fiber reinforced plastics

CompositesReloaded status update – Collaborative production scenarios for fiber reinforced plastics

Collaborative production environments can be considered an enabler for more flexible FRP fabrication – especially for SMEs. In the course of the CORNET project CompositesReloaded, a first collaborative process was implemented and is being presented in the following.

Traditional robot cells are not suitable for the production of small batches because of their high invest costs, long programming times and fixed position. For this reason, in recent years small and medium-sized enterprises (SMEs) increasingly need more flexible, semi-automated production scenarios which exploit the advantages of both, human and machine. The high flexibility and cognitive ability of a human worker is combined with the high productivity and reproducibility of robots. In this context, the application of collaborative robots (co-bots) seems promising.

Therefore, within the CompositesReloaded project, a co-bot assisted production cell for the manufacturing of FRP has been implemented (Fig. 1). As a first demonstrator, a suitcase is examined. Especially handling tasks are carried out by a co-bot. Furthermore, the draping of the carbon fabrics is realized by a tool developed for this purpose. The use of this production scenario can reduce production costs by approximately 20 %.

Fig. 1: Collaborative production environment (left) and demonstrator suitcase (right)

Against the benefits of co-bots, their use is restricted by their low load capacity and reach as well as high safety concerns. Therefore, safe co-bot tools have to be developed which allow the use in a collaborative working environment. Besides, already in the design phase of components, the “design for automation” has to be considered.

For the upcoming steps within the project it is intended to increase the components’ complexity and address real problems from SMEs. Therefore, companies from the users’ committee provided components that are currently mainly built manually. Specifically, these are an engine hood for the automotive industry (provided by Airconcept GmbH, https://www.airconcept-enterprises.com) and a stiffener element for aerospace applications (provided by Sabca Limburg N.V., https://www.sabca.be).

The project is being carried out in collaboration between Sirris, Belgium and the Institut für Textiltechnik (ITA) of RWTH Aachen University, Germany. The project was launched in March 2018.

Contact

Florian Brillowski


Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80-27662
florian.brillowski@ita.rwth-aachen.de

Hannah Dammers


Research Assistant
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 220 95
hannah.dammers@ita.rwth-aachen.de

Hydrogen Storage: An advanced manufacturing technique for light-weight composite pressure vessels.

Hydrogen Storage: An advanced manufacturing technique for light-weight composite pressure vessels.

The ITA Aachen is working extensively on composite pressure vessels (CPV) for hydrogen storage. A novel technique for the manufacturing of filament winded pressure vessels is presented in this article.

 Reduction of the greenhouse gas emission to at least 40% in comparison to the levels from 1990; at least 32% of the total energy demands covered through renewable energy resources; [1] These being the key targets for the EU climate and energy framework, extensive research towards the realization of this target are already in progress. Seasonal nature of the renewable energy resources, calls for a suitable storage system. Available battery technologies are not suitable for storage of large amounts of electricity for an extended period. Herein hydrogen storage is very promising.

Heralding the targets for zero emission transportation are the battery and hydrogen fuel cell technologies. On-board hydrogen storage being a major challenge in the development of fuel cell based automotive propulsion application, the Institute für Textiltechnik (ITA) in Aachen and the RWTH Aachen University is heavily involved in the developing novel manufacturing techniques.

In general, optimization of the manufacturing process is not trivial, as numerous factors come into play. For example, cost of the product is dependent on the production time, material, labor intensiveness, etc. Specifically, in fiber composites, fiber material, fiber orientation, have a major influence on the structural properties. Complex winding layout calls for longer processing time, however unstructured layout may require more material for the same loading condition. Likewise, many other critical questions can be raised, which calls for a detailed research. The ITA, with its comprehensive facility, makes us a unique organization to research from the fiber manufacturing till the end product, here being the pressure vessel.

One among this pursuit, reduction of the processing time, has led to the development of the Multi-Filament Winding (MFW) technology [2, 3]. An international collaboration between the Murata Machinery Japan and the ITA Aachen, has facilitated us to research further on this technology [4, 5]. The ITA is involved in a number of research projects through national and international collaboration for the further development of this technology.

Concomitant to the process development, the ITA has also collaborative projects where the structural and material properties are extensively researched. Along with this, we are also currently developing a novel fiber based technology for the structural health monitoring (SHM) of the pressure vessels. An efficient SHM system could lead to the reduction the factor of safety and hence the cost. The maximum efficiency/benefit can be harnessed through a synergistic combination of all these technologies.

References:

[1] Eurostat website: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Renewable_energy_statistics
[2] T. Uozumi, A. Ohtani, et al., ‘Non-crimp Tubular Preforming with Automation System and High Productivity’, ICCM20, July 2015 Copenhagen.
[3] T. Hyodo, Y. Kanemitsu, et al., ‘Mechanical Properties Of CFRP Pipes Made By Multi Filament Winding Method (MFW)’, ICCM20, July 2015 Copenhagen.
[4] Composite World: https://www.compositesworld.com/articles/filament-winding-reinvented
[5] ITA Aachen: http://www.ita.rwth-aachen.de/cms/ITA/Die-Organisationseinheit/Aktuelle-Meldungen/~mzch/Innovative-Wickeltechnik-in-einer-intern/?lidx=1

Contact

Kumar Jois


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

Development of a combinde Spreading and Sizing Line for Unsized Carbon Fibres: Spreizsize

Development of a combinde Spreading and Sizing Line for Unsized Carbon Fibres: Spreizsize

The aim of the government funded project is the development of a standalone production line which can either spread and size unsized carbon fibers.

Due to their excellent mechanical properties, carbon fibers are increasingly used in the form of carbon fiber reinforced plastics (CFRP) in lightweight construction. Carbon fibers have excellent properties, especially in the fiber direction. Orthogonal to the fiber direction, however, the properties are only average. In order to make optimum use of the potential of carbon fibers, carbon fiber rovings are often spread. During spreading the individual filaments of the roving are deposited parallel to each other so that the forces can be optimally applied to the fiber.

The spreading process is often limited by the sizing applied to the fiber. Most sizing is based on an epoxy matrix and therefore bonds the individual filaments together. This damages the fibers filaments when they are spread. However, sizing is indispensable for use in composite components. The primary task of sizing is to improve the fiber-matrix adhesion in the finished composite component. Furthermore, the sizing enables a damage-free further processing of the rovings in subsequent processes such as weaving.

The aim of the project is to develop a system for spreading unsized carbon fibers and subsequently applying a carbon fiber sizing to fix the individual filaments. The aim is to minimize the number of filament breakage rates and the basis weight (< 0.5 % and < 80 g/m² respectively). Using a standalone variant, CFRP manufacturers also have the option of producing spread yarns with a sizing and degree of spread designed for their requirement profile. A particular challenge is the processing of unsized fibers on the line. The damage to the unsized roving has to be minimized by special roller surfaces and adjustment of process parameters.

The project is being carried out in collaboration between M&A Dieterle GmbH, Germany and the Institut für Textiltechnik (ITA) of RWTH Aachen University, Germany. The project was launched in September 2018.

Contact

Felix Pohlkemper


Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 241 80 23447
Felix.Pohlkemper@ita.rwth-aachen.de

Investigating the effects of binder fixation for spread tow fabrics

Investigating the effects of binder fixation for spread tow fabrics

The effects of binder fixation on the mechanical properties, as well as processability of spread-tow tapes and spread-tow fabrics will be investigated at ITA within the recently started AiF-IGF project “Tape2Demand”.

Thin-ply reinforcements with low areal weights represent the next step in the development of fiber-reinforced plastics (FRPs). Very thin individual layers lead to significant improvements in the mechanical properties of a composite. Thin-ply composites show better damage tolerance trough higher resistance to crack propagation, better fatigue and failure behavior (esp. under compression) and are therefore particularly promising for high performance applications (e.g. aerospace).

Thin-ply composites can be achieved by spreading conventional carbon fiber rovings to tapes with higher width and lower thickness. In terms of production speed and good processability of spread-tow tapes in subsequent processes (e.g. tape weaving or tape laying), the bottleneck of the spreading process is the fixation of the spread-tow tape via binder application. Without fixation, spread-tow tapes demonstrate low cohesiveness perpendicular to the fiber direction and are therefore difficult to handle. For this reason, binder application is a crucial step in fiber spreading processes. Besides the stability of the tape, the binder also functions as a bonding agent between individual layers in tape laying processes. In contrast to prepreg tapes, dry binder fixated tapes do not rely on expensive autoclave processes.

Since the effects of the various parameters of binder fixation (e.g. binder system, binder material, binder quantity) on mechanical properties and processability of spread-tow tapes is not fully understood, the influence of these parameters will be investigated within the recently stated Aif-IGF project “Tape2Demand”. The aim of this research it to examine which type of binder system (powder, veil, hotmelt etc.) and quantity is suited for which application and how these parameters effect properties like tensile strength, bending behavior, compression-after-impact, drapeability, permeability etc. Another aim is to significantly decrease the price of spread-tow binder fixated tapes, which currently exceeds 1000 €/kg in some cases. Focusing on dry binder tapes, it is ensured that the results of this project are especially relevant to smaller companies which do not have access to expensive infrastructure like autoclaves. Material cards will be derived from the results and will provide an easy access to the findings of this project.

Fig.1 Bindertapes

 

Fig.2 Tapes-2-Demand

Contact

Philipp Quenzel


Scientific Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 23444
Philipp.quenzel@ita.rwth-aachen.de

Large scale concrete floor slabs with textile reinforcement

Large scale concrete floor slabs with textile reinforcement

In the joint project LiPa of the ITA RWTH Aachen University and industry partner Basamentwerke Böcke GmbH, thin-walled large scale concrete floor slabs with edge lengths of up to three meters are developed.

Current state of the art concrete floor slabs, as used for pavements and public places, are limited in their size. For edge lengths of more than two meters, a steel bar reinforcement is necessary to prevent the slabs from breaking during transport due to their high weight. To impede the corrosion of the steel reinforcement, a high thickness of the concrete slabs is required. This leads to very heavy concrete slabs, which are difficult and expensive to transport and install on site.

The recently launched project “Lightweight Pavement” – LiPa – of the ITA of RWTH Aachen University and industry partner Basamentwerke Böcke GmbH aims to develop a textile reinforced concrete floor slab, enabling edge lengths of up to three meters with a thickness of only four centimeters.

To achieve this goal, the partners will develop a tailored reinforcement textile and concrete mixture as well as an efficient production process. Because of a highly competitive and price sensitive market, traditional textile reinforcement materials, such as carbon, are not economically viable. Standard glass fibers are not suited due to the high alkalinity of the concrete. Instead, more uncommon materials, such as AR-glass and basalt, are considered. Following the standard lightweight construction paradigm, only as much reinforcement as absolutely necessary is used.

By reducing the thickness of the concrete slabs whilst increasing their size, the new slabs offer a multitude of advantages. The reduced weight will allow for easier handling, whilst the increased size will reduce installation times since fewer slabs need to be installed. In addition, the reduced thickness decreases the necessary storage space, reducing logistics costs. Another important advantage is a reduction in CO2-emissions, since less concrete is used. The production of cement used for concrete produces about 6.5 % of the global CO2-emissions, thrice the amount emitted by the global aviation industry. Therefore, saving on concrete is essential to achieve global emission reduction targets.

The project is funded by the BMWI within the ZIM program.

Aim of the project LiPa

Contact

Martin Scheurer


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

OptiTFP - Development of a material- and load-path optimized TFP preform technology for the

processing of multi-component mixed fibers in thermoplastic composites

OptiTFP – Development of a material- and load-path optimized TFP preform technology for the processing of multi-component mixed fibers in thermoplastic composites

The Tailored Fibre Placement (TFP) is an embroidery process used for preforming with the highest fiber efficiency. The reinforcement fibers can be placed in orientation to the load path and in near-net shape leading to very low fiber waste below 5 %.

Thermoplastic fiber reinforced plastics (FRP) are gaining increasing economic importance. Compared to thermoset FRP, thermoplastic FRP are suitable for large series applications in the automotive sector due to their short process times and low post-processing costs and have the advantage of better recyclability.

The TFP process can be also used for feeding multiple fiber materials for the preforming process. This allows functionalization for thermoplastic composite components. It can significantly increase composite properties such as damping or impact behavior. In addition, electrically conductive functional fibres (e.g. copper wire) can also be supplied.

A challenge when processing these preforms into thermoplastic FRP is the high melt viscosity of such thermoplastic matrix systems. One way of reducing the flow paths and thus also the cycle time when processing these matrix systems is to use hybrid yarns, which are already mixed reinforcing and thermoplastic filaments. This minimizes the flow paths of the thermoplastic matrix and ensures that the preforms can be processed cost-effectively into thermoplastic FRP. The deficit in the use of conventional hybrid yarns lies in the limited choice of materials and the material structure which is not adapted to embroidery. This can lead to incomplete fibre impregnation during processing and thus to poor mechanical and optical properties of the subsequent FRP components.

The project “OptiTFP” focuses on the development of a direct placement of reinforcing and thermoplastic fibers under the additional feeding of functional fibers in an inline mixing process during the TFP embroidery process. In addition, a consolidating process is being developed for a high finishing quality of FRP produced from the TFP preforms.

The company Digel Sticktech GmbH & Co. KG, Pfullingen, is developing a spreading and mixing module for the homogeneous, planar TFP of various fiber materials. The company Steinhuder Werkzeug- und Apparatebau Helmut Woelfl GmbH, Wunstorf, develops a tool with active heating and cooling zones so that locally different surface temperatures can be set in the tool. At the ITA of RWTH Aachen University, suitable fiber materials are selected together with the project partners. The validation of the entire process chain by the production and subsequent testing of demonstrators is also carried out here.

“OptiTFP” project is funded by the Federal Ministry of Economic Affairs and Energy (BMWi) within the framework of the Central Innovation Programme for SMEs (ZIM) and was launched in December 2018.

Contact

Max Schwab


Researcher
Institut für Textiltechnik (ITA) of RWTH Aachen University
Phone: +49 (0) 241 80 – 23473
Max.Schwab@ita.rwth-aachen.de