Search

There is a considerable need for research to fully exploit the application potential of adaptive fiber-reinforced plastics based on functional materials, in particular with regard to industry-specific solutions. Hence, this paper presents the development of a locomotion mechanism based on fiber-elastomer composites with shape memory alloys. In order to attain this goal, shape memory alloys were textile-technically integrated into the reinforcing fabric in the weft direction using flat knitting technology. The functionalized reinforcing fabrics was infused by the vacuum assisted resin infusion with an elastomeric silicone matrix system. Later, an extensive electro-thermal-mechanical characterization of the fiber-elastomer composites by varying electrical power caused by the varying voltage amplitude was completed. The fiber-elastomer composites were then shaped in a cross-country ski as an example of locomotion mechanism. Finally, the forward movement of the cross-country skiers was realized by activating the shape memory alloy in the left and right leg.

Electrically conductive fibers are required for numerous fields of application in modern textile technology. They are of particular importance in the manufacturing of smart textiles and fiber composite systems with textile-based sensor and actuator systems. Elastic and electrically conductive filaments can be used as strain sensors for monitoring the mechanical loading of critical components. In order to produce such sensorial filaments, thermoplastic polyurethane (TPU) is compounded with carbon nanotubes (CNT) and melt spun. The mechanical performances of filaments produced at different spinning speeds and containing different amounts of CNT were tested. Furthermore, the correlation between the specific electrical resistance of the filaments and the mechanical strain were analyzed depending on the CNT-content and the spinning speed.

The internet of things is a key driver for new developments in the fields of medicine, industry 4.0 and gaming. Consequently, the interaction of virtual and real world by smart interconnecting of devices in our everyday life is the basis idea of the Cluster of Excellence "Centre for Tactile Internet with Human-in-the-Loop" (CeTI) at TU Dresden. To enable a user-centric approach in CeTI innovative textile structures, mainly knitted smart gloves, and their functionalization by integration of sensors and sensory yarns are focus of research activities.

This research focuses on the electromechanical strain-sensing behaviour of steel wires on the fiber and composites scale. The electromechanical properties are investigated by using a uniaxial fiber tensile test with a simultaneous electrical resistance measurement. Further, this work conducts a comprehensive stress analysis of textile reinforced concrete (TRC) specimen in quasistatic and dynamic tensile tests by using integrated steel wires in a textile 3D-weaving reinforcement as piezoresistive in-situ-sensors. The results are compared to optical strain measurements using digital image correlation (DIC). The acquisition and analysis of the electrical resistance changes of the steel wire sensors enable an in-situ stress analysis as well as a better understanding of the mechanical response of the TRC specimen under different loading scenarios.

The Cluster of Excellence “Centre for Tactile Internet with Human-in-the-Loop (CeTI)” deals with developments and inventions concerning smart devices used in many fields, e.g. industry 4.0, medicine and skill learning. These kind of applications require smart devices, sensors, actors and conductive structures. Textile structures address these applications by meeting requirements such of being flexible, adaptable and wearable. Within this paper, the development of a protective coating for electrically conductive (EC) yarns is captured. These EC yarns are nowadays often used for smart textile applications. One challenge in their application is the integration into textile structures. Often, the handling and use of EC yarns lead on the one hand to damages on the surface of the yarn and on the other hand to reduced electromechanically characteristics. This paper aims to characterize these EC yarns in regard to develop a suitable protective coating based on polypropylene (PP). To achieve this development, an extensive characterization of the EC yarns as well as the protective coating itself is important. The surface free energy (SFE), the topographical and the chemical characteristics are necessary for developing a suitable protective coating. However, the yarns are characterized before and after implementation into the textile structure and furthermore after the coating respectively with the developed finish.

Adaptive fiber-reinforced plastics (FRP) contain actuators that enable the controlled modification of system states and characteristics. The textile-technical integration of actuators, in particular shape memory alloys, into reinforcing fabrics has increasingly been applied in recent years. The objective is to achieve optimum force transmission from shape memory alloy to FRP, long-term stability of adaptive FRP as well as a maximum degree of deformation. This paper presents the development of actuator networks for adaptive FRP, where two shape memory alloys are integrated into reinforcing fabrics by means of open reed weaving technology. After infusion of the functionalized reinforcing fabrics, the deformation behavior of adaptive FRP was characterized with variable actuator switching frequencies (≥ 1 Hz) or actuator activation times (≤ 1 s).

Concrete is extremely vulnerable against impact loading due to its low tensile strength and pronounced brittleness. The application of thin strengthening layers, containing Textile Reinforced Concrete (TRC) and Strain-Hardening Cement-based Composites (SHCCs) in a ductile cement-based composite, is a promising solution to enhance the impact resistance of existing concrete structures. Three-dimensional (3D) textile structures exhibit numerous advantages over two-dimensional (2D) ones, most importantly higher shear, bending and energy absorption capacity, hence, appear to be instrumental in providing sufficient reinforcement to the target strengthening layers. However, design variability and optimization possibility of available 3D textile reinforcement are restricted. This paper presents the development of novel textile-based 3D truss reinforcement that can overcome these limitations. On the basis of woven 3D cellular structures, innovative pyramidal 3D truss reinforcement with favorable load-bearing capacity as well as notable energy absorption capability is developed and successfully realized. To investigate the feasibility and efficacy, cement-based composite consisting SHCC and newly developed pyramidal 3D truss reinforcement is prepared and tested under high-speed tensile loading as well as transversal impact loading. The experimental results show that woven 3D truss reinforcement is highly compatible with SHCC, and significantly enhances its impact resistance. Furthermore, SHCC reinforced with novel pyramidal 3D truss structure remarkably outperforms that with 2D carbon reinforcing structure approved for commercial use.

This paper presents the manufacturing process and electromechanical characterization of highly stretchable textile strain sensors. These sensors can be used in self-sensing soft robots or motion tracking. To improve linearity and compliance of silver-plated yarns, the braiding technology is used to fabricate both resistive and capacitive strain sensors. Braiding is a highly productive and automated process and the resulting sensor properties can be improved. Moreover, the braids can be further processed to complex textiles. In the fabrication process different base materials are used and the braiding density as well as the composition of the conductive threads in the braid are varied. With the produced samples electro-mechanical characterization experiments are carried out to analyze the sensors’ properties, e.g. gauge factor, linearity, hysteresis and compliance. The experimental results are correlated with the material and process parameters. Both, braiding density and base material, have an enormous influence on the sensor characteristics. The most promising sensor type was integrated into a soft actuator. This demonstrates the feasibility of such textile sensors to provide self-sensing capabilities and proprioception to soft robots.

Continuous load monitoring of fiber-reinforced composites represents a complex challenge for the composite sector. In this paper, the development and characterization of piezoelectric sensors for structural health monitoring applications based on polyvinylidene fluoride (PVDF) are presented. The basic sensor structures are melt spun bicomponent filaments in a core-sheath configuration. The core is a volumetric mixture of polypropylene (PP) and Pre-Elec PP, a PP-compound modified with carbon black. The sheath is made of PVDF. Three variants with increasing volumetric Pre-Elec ratio in the core (50 vol.%, 60 vol.% and 70 vol.%) are manufactured and analyzed by conducting optical and resistance measurements as well as tensile tests. In the subsequent process step, the bicomponent filaments are braided with copper fine wires. The PP core and copper braiding of the coaxial tricomponent yarn are used as inner and outer electrode, respectively. By generating an electrostatic high voltage field between these electrodes, the PVDF interlayer is subjected to contact polarization to initialize the piezoelectric effect. The piezoelectric characteristics and thereby the sensory potential of the produced sensor yarns are quantified and analyzed on the fiber and composite scale by investigating their piezoelectric behavior during cyclic tensile tests. The results of the different sensor yarn variants are compared with each other by evaluating the measured voltage signal as a function of the induced cyclic stresses.

Zusammenfassung Für die Etablierung von Carbonbeton in der industriellen Praxis sind Prüfverfahren zur reproduzierbaren Bestimmung der mechanischen Kennwerte textiler Bewehrungsstrukturen essentiell, insbesondere der Zugfestigkeit. Zu diesem Zweck wurde im Rahmen des Forschungsvorhabens C³-V1.2 ein neuartiges Prüfverfahren entwickelt und qualifiziert. Mit diesem Verfahren können Carbonfaserstränge aus flexiblen, steifen und bedingt biegbaren Bewehrungsgelegen hinsichtlich ihrer Zugfestigkeit mit geringem Präparationsaufwand und reproduzierbar charakterisiert werden.

Electrically conductive filaments are used in a wide variety of applications, for example, in smart textiles and soft robotics. Filaments that conduct electricity are required for the transmission of energy and information, but up until now, most electrically conductive fibers, filaments and wires offer low mechanical elongation. Therefore, they are not well suited for the implementation into elastomeric composites and textiles that are worn close to the human body and have to follow a wide range of movements. In order to overcome this issue, the presented study aims at the development of electrically conductive and elastic filaments based on a coating process suited for multifilament yarns made of thermoplastic polyurethane (TPU). The coating solution contains TPU, carbon nanotubes (CNT) and N-Methyl-2-pyrrolidone (NMP) with varied concentrations of solids and electrically conductive particles. After applying the coating to TPU multifilament yarns, the mechanical and electrical properties are analyzed. A special focus is given to the electromechanical behavior of the coated yarns under mechanical strain loading. It is determined that the electrical conductivity is maintained even at elongations of up to 100%.

Die Reduzierung des CO2-Ausstoßes und die Ressourceneffizienz treiben die Substitution konventioneller Konstruktionsmaterialien durch faserverstärkte Kunststoffe (FVK) voran, die durch die Integration von Funktionsmaterialien, wie Aktuatoren mit sensorischer Rückkopplung für präzise Stellbewegung der FVK, noch effizienter eingesetzt werden können. In diesem Beitrag wird die Entwicklung adaptiver FVK auf der Grundlage der textiltechnischen Integration von Sensor-Aktor-Netzwerken in Verstärkungsgewebe für die hochpräzisen in-situ-Mechanismen in FVK vorgestellt.

The textile-technical integration of shape memory alloys into reinforcing fabrics for the development of adaptive fiber-reinforced plastics (FRPs) has been developed in recent years. This is aimed at reproduction, automation, and series production as well as reduced delamination of shape memory alloys in FRPs, and higher force transmission from shape memory alloys to FRPs. This type of integration can be executed in several ways, for example, by weaving or by tailored fiber placement technology. We present a comparative study of the functional properties of adaptive FRPs based on both types of technology. In order to conduct this study, functionalized reinforcing fabrics for the formation of adaptive FRPs were produced by open reed weaving and tailored fiber placement technology. Subsequently, they were infused by means of a thermosetting resin system. After the fabrication of adaptive FRPs, their functional properties were characterized and evaluated. Results show that the maximum deformation of adaptive FRPs produced by open reed weaving technology was higher than those produced by tailored fiber placement technology. Therefore, the adaptive FRPs produced by open reed weaving technology are more suitable for the formation of grippers, aerodynamically effective flaps, or robotic hands than that of adaptive FRPs produced by tailored fiber placement technology.

Novel textile moisture sensors based on multi-layered braiding constructions offer attractive monitoring possibilities for many application fields of e-textiles (electronic textiles), especially for ambient air, which is the main focus of this work. In this paper the theoretical foundations and the production, as well as the procedural, mechanical and humidity tests on newly developed, textile-based sensors for moisture measurement are described. The sensor, which is based on a capacitive measurement principle, was tested in environments ranging from 22% to 94% relative humidity. Within this range, the electrical capacitance of the sensors changed up to 135% of the base capacitance, giving it a very high sensitivity.

Over the last decade, carbon fibre-reinforced composites (CFRP) are increasingly used as lightweight material for various industrial applications. Due to the anisotropic material structure and its corresponding properties, novel design concepts and processing technologies were developed to further harness the material inherent lightweight potential. However, the material degradation in long-term use and failure behaviour is still considered a challenging issue for material scientists and engineers in particular. Therefore, concepts for structural health monitoring and their suitable implementation is still a major research topic. Among others, one solution uses the conductivity of carbon fibre yarns and their suitability to act as in-situ strain sensors. In the present work, the measurement principle bases on the usage of the piezo-resistive effect, meaning that every mechanical strain of the roving filaments causes a correlative change of the measurable electrical resistance. Since, these sensory elements need shielding from their surrounding carbon filaments of the composite structure, suitable fibre-based dielectric jackets have been developed with a wide range of suitable materials and textile processing technologies. In this contribution, the influence of the integrated carbon fibre sensors on the resulting mechanical performance of the composite structure is evaluated using an analysis of variances approach. Beyond that, the local composite morphology is analysed to evaluate the composite microstructure.

In the lightweight material industries, the current focus is on fiber-reinforced plastics, in particular on carbon fiber-reinforced plastics (CFRPs), since they offer higher relative specific tensi...

The integration of functional material, such as actuator material, is an essential aspect for the multi-functionality and resource efficiency of fiber-reinforced plastics (FRPs). By integrating a textile-based actuator into reinforcing fabrics during the production process, single axis and intrinsic adaptive FRPs can be produced, and these can change their form according to requirements. However, this paper presents the effect of thickness ratio and integrated weft yarn column number in shape memory alloys on the deformation behavior of adaptive FRPs. In order to achieve this aim, shape memory alloys were converted into hybrid yarn in the form of a core-sheath structure before being textile-technologically integrated into the reinforcing fabrics using weaving technology. The thickness variation was achieved by the warp as well as weft yarn density and the type of interlacement. These preforms were infused by a thermosetting resin system . The adaptive FRPs were tested electro-mechanically with respect to their maximum deformation. Results reveal that the maximum deformation of adaptive FRPs is enhanced by increasing the thickness ratio and the integrated weft yarn column number in shape memory alloys.

Considering their energy and resource efficiency, fiber-reinforced plastics (FRPs) have been displacing metals and metal alloys for lightweight constructions. During the semiautomated manufacturing process of FRPs, and in particular during the laying of reinforced fabric layers, foreign bodies are enclosed within them, which in turn reduce the mechanical performance of FRPs. The research project presented in this article investigated if the loss in mechanical properties, such as tensile, flexural, and impact strengths, depends on the position of defined local defects, polytetrafluorethylene (PTFE) in this case, in the thickness direction of FRPs. In order to achieve this aim, PTFE was placed in different layers of reinforcing fabric before infusion. Subsequently, the mechanical performance of the fabricated FRPs was tested and evaluated. On the basis of the experiment, it can be concluded that the loss in mechanical properties was maximal if PTFE was laid in the middle position of FRPs in the thickness direction.

The process of integrating smart materials into fiber-reinforced plastics has been used increasingly to create different high-performance products for lightweight applications. This paper presents the development of an adaptive morphing wing based on fiber-reinforced plastics with shape memory alloys integrated into the reinforcing fabrics. Two types of preforms with varying numbers of integrated weft yarns in shape memory alloys were manufactured for a wing structure on a weaving machine using the pleated woven fabric technology. Subsequently, the realized preforms were infiltrated by a thermoset matrix and characterized mechanically to derive a preferred variant. After developing the adaptive morphing wing, its deformation behavior was characterized by varying current flow and time through shape memory alloys. Results revealed that maximum deformation of the investigated adaptive morphing wing was achieved at a current flow and time of 1 A and 60 s, respectively.

The increasing demand for fiber reinforced plastics for different high-tech lightweight applications requires their continuous development, for example, by means of high functional density. Among various smart materials, fiber reinforced plastics can be functionalized by actuator materials, in particular shape memory alloys. This paper presents a statistical approach to the fabrication of adaptive pleated fiber reinforced plastics. Three geometrical factors – pleat thickness, pleat height and the spacing between two pleats were identified by the half-normal probability plot that affect the deformation of adaptive pleated fiber reinforced plastics during the activation of shape memory alloys. Overall, four responses were evaluated by means of the design of experiment. Significant statistical models were found for the deformation, level loss per cycle, heating and cooling speed of adaptive pleated fiber reinforced plastics. These statistical models were validated through experimental data by the goodness of fit function. The results of the statistical model tended to fit experimental results.

For reinforcement in fiber reinforced plastic and concrete applications, the knowledge of the high-velocity impact and crash behavior of typically used high-performance fibers, such as carbon fibers (CF), becomes an important aspect for designing and dimensioning new composite components. More important than the impact velocity is the resulting strain rate in the fiber, which defines the failure behavior. In current literature, there is still an open gap for fiber material testing for strain rates between 100 and 1000 1/s, which is difficult to close with the existing measurement setups, i.e. between servo-hydraulic tensile testing machines and Split-Hopkinson-tension-bars. A rotary drive principle is proposed where the challenge arises in coupling the force, in a reliable clamping of the specimens and in high-speed acquisition of the stress-strain curve. In the implementation process, speeds up to 40 m/s were currently achieved, which corresponds to a strain rate of 267 s-1 for a specimen length of 150 mm. The specimen and the moving elements were prepared with stochastic patterns and evaluated by means of digital image correlation (DIC). The force signal is recorded and correlated from a piezoelectric load cell. Additional information on the energy dissipated by the tensile test was acquired by analyzing the engine control records. The evaluation of high-speed images by DIC shows that there is a partially elastic impact and acceleration reaches its maxima before the specimen’s rupture. Thus, for a precise evaluation, the stress equilibrium has to be taken into account and the impact process has to be further optimized.

A steadily increasing application of fibre-reinforced plastics in the field of lightweight construction has been observed in the course of the past two decades. Currently a major challenge in the growing high technology market is the quality assurance of manufactured fibre-reinforced plastic components. During different stages in the manufacturing process of fibre-reinforced plastics, defects of different types and sizes are enclosed in them, exerting a destructive influence on the performance of fibre-reinforced plastics in various practical applications in terms of strength, stiffness and brittleness. Thus the aim of this research project was to investigate the effect of defined local defects on the mechanical properties, such as tensile, flexural and impact properties, of fibre-reinforced plastics, in particular carbon fibre-reinforced plastics. Results show that these mechanical properties depend significantly on the type and size of defect.

A coreless manufacturing process for generic 3D rigid frame topologies will be introduced in this paper. The aim is to extend the field of filament winding from mainly 2D-shells and some exceptional cases of 3D rigid frames. This manufacturing process employs a coreless translation cross-winding method in order to continuously deposit a roving around deflection points in space. On this basis, a design methodology is being created and deductively verified by designing a beam for a three-point bending load case. The composite beam is designed on a macro level simulation approach to match the stiffness of a reference aluminum profile, which is commonly employed as structural component for robotic gripper systems in automotive assemblies. The performance of the beams is subsequently compared by three-point bending experiments. This demonstrates that the composite beam offers equivalent stiffness and strength properties with a weight-reduction potential of nearly 50% for bending loads.

Carbon particle-filled elastomers are a widely researched option to be used as piezoresistive strain sensors for soft robotics or human motion monitoring. Therefore, various polymers can be compounded with carbon black (CB), carbon nanotubes (CNT) or graphene. However, in many studies, the electrical resistance strain response of the carbon particle-filled elastomers is non-monotonic in dynamic evaluation scenarios. The non-monotonic material behavior is also called shoulder phenomenon or secondary peak. Until today, the underlying cause is not sufficiently well understood. In this study, several influencing test parameters on the shoulder phenomena are explored, such as strain level, strain rate and strain history. Moreover, material parameters such as CNT content and anisotropy are varied in melt-spun CNT filled thermoplastic polyurethane (TPU) filament yarns, and their non-monotonic sensor response is evaluated. Additionally, a theoretical concept for the underlying mechanism and thereupon-based model is presented. An equivalent circuit model is used, which incorporates the visco-elastic properties and the characteristic of the percolation network formed by the conductive filler material. The simulation results are in good agreement when compared to the experimental results.

This chapter addresses sensors and actuators for three main sensory modalities: hearing, vision, and touch. Technology in recent years was often focused on flat displays, e.g., or smartwatches. In contrast, the focus of this chapter is on wearable technologies of the post-smartphone area, allowing rich sensory input and output modalities. New approaches for tactile feedback include fiber-based sensors and actuators for e-textiles as well as complex 3D-fiber structures. Wearable sound sources and innovative sound-projection solutions using perceptual knowledge can replace complex distributed channel systems. One way to reduce latencies in vision are Organic Light-Emitting Diode (OLED) eyeables, that have the potential to significantly improving reaction time and power consumption. Combining the expertise of human perception and action with that on sensors and actuators contributes to augmented perception and interaction to exchange perceptual knowledge, which is needed for holistic sensor and actuator development. Moreover, sensors and actuators combined with tactile electronics in terms of flexible electronics and circuits for interfacing/processing explore new technologies for haptic and robotic systems.

For the next generation of Soft Robotics novel materials are needed that overcome the limitations of established active materials like shape memory alloys or dielectric elastomer actuators. These new actuator types should offer fast actuation and good electromechanical coupling. In this publication, the manufacturing process and the resulting prototype of a helical dielectric polymer actuator are presented. The actuator material consists of several layers of thermoplastic elastomer and thermoplastic polymer layers with conductive fillers that are thermally bonded and stretched afterwards, which leads to self-coiling into a helical configuration. In the targeted set-up the thermoplastic dielectric layer, that is compressed by Maxwell pressure, is significantly thinner but much easier to handle than silicone films frequently used in dielectric elastomer actuators. Several manufacturing strategies are discussed and experimentally evaluated. This includes the use of different materials, their preliminary treatment, the implementation of electrically conducting layers functioning as electrodes and the contacting of the conducting layers. By identifying feasible settings and properties for these parameters, potential defects occurring during manufacturing or high-voltage activation can be minimized. By pre-stretching and then releasing a thin strip of the laminate structure, a helix is formed. The resulting prototype actuator set-up is characterized under voltages of 3 kV and shows high-speed actuation at deformation speeds of > 5 %/s. Due to the helical configuration, the observed contraction is orders of magnitude higher than the theoretical value for the corresponding flat configuration, showing the potential of the newly developed actuator material.

Novel textile temperature sensors based on strain-relieved braiding constructions offer attractive monitoring possibilities for numerous application fields involving e-textiles in general, and medical textiles in particular. Thus, the research work presented in this paper focused on theoretical foundations, manufacturing, and procedural, mechanical as well as thermal testing of these newly developed, textile-based sensors for temperature measurements. The median basic resistance of the scalable sensor yarns using a helical stainless steel wire is about 0.81 Ω/mm. Within the temperature range of 22 to 40℃, the developed sensor yarn has a mean linearity deviation of 0.028 K. The measured temperature coefficient is 0.68 × 10−3 K−1, which correlates with the properties of the stainless steel wire.

The growing demand for fiber-reinforced plastics for different high-tech lightweight applications requires their consistent and continuous development with a high functional density. The integration of actuator-like materials for developing adaptive reinforced fabrics can increase the market value of fiber-reinforced plastics. This paper reports on the development of adaptive pleated woven fabrics based on shape memory alloys using weaving technology. For the development of these fabrics, a systematic weave pattern was generated. Adaptive pleated woven fabrics were manufactured on a rapier weaving machine with a jacquard unit. By varying the pleat thickness, pleat width and the spacing between two pleats, eight types of adaptive pleated woven fabrics were developed, and their weaving-technical implementation for the subsequent infusion was evaluated. The flexural modulus of infused adaptive pleated woven fabrics was characterized by bending. Experimental results showed that the spacing between two pleats predominantly influences the flexural modulus of impregnated adaptive pleated woven fabrics.

The application of shape memory alloys (SMAs) for the development of adaptive fiber-reinforced plastics has been expanding steadily in recent years. In order to prevent matrix damage and optimize the actuating potential of SMAs during the process of thermally induced activation, a barrier layer between SMAs and the matrix of fiber-reinforced plastics is required. This article approaches the textile technological development of SMA hybrid yarns as a core–sheath structure using friction spinning technology, whereby the SMA serves as the core. Four types of hybrid yarns are produced by varying the number of process stages from one to three, as well as the core and sheath materials. The decoupling of the SMA from fiber-reinforced plastics is crucial for optimizing the actuating potential of SMA, thus it is tested by means of the pull-out test. Although the material loss coefficient increases by raising the number of process stages, the three-stage processing of SMA hybrid yarn with an additional glass roving is found to be the most suitable variation for decoupling SMA from the matrix of fiber-reinforced plastics.

Textile-based lightweight structures offer various possibilities for the design of tailored structures by the selective choice of materials and their processing into textile semi-finished products and fiber-reinforced plastics. Lightweight structures with a high mechanical load capacity are feasible by developing fiber-reinforced plastics with adaptive properties that are able to adapt their characteristics, e.g. geometry or stiffness, to external influences. Thus, the application potential of fiber-reinforced plastics can be further expanded. In this paper, we present novel adaptive fiber-reinforced plastics based on textile semi-finished products with integrated shape memory alloys and their mechanical characterization. The shape memory alloy is textile technically integrated and converted into friction spun hybrid yarn. Next, the produced hybrid yarn is integrated with plain, twill and satin woven reinforcement fabric in the weft direction during the shedding operation in weaving. Adaptive fiber-reinforced plastics are developed by infusing textile semi-finished products. Subsequently, the mechanical characterization of the adaptive fiber-reinforced plastics is carried out. Results show that, by integrating shape memory alloys into adaptive reinforced fabrics, the mechanical performance of fiber-reinforced plastics can be tailored.

Coreless filament winding technologies possess the potential to flexibly produce lightweight rigid frame structures at comparably low costs. The key to versatility, geometrical freedom and cost-effectiveness is the avoidance of core elements. Existing research on the filament winding of rigid frames focusses primarily on “isotruss” or “lattice” structures, manufactured by depositing fibers on polygon-shaped mandrels with carved-out gaps. Therefore, an investigation into the performance of coreless wound laminates and their material characteristics under process conditions is performed. Therefore, generic 2D specimens were manufactured on a new fully automated 3D winding equipment and successively exposed to incineration, micro-CT analysis and tensile testing. The benefits of core elements are evaluated by additional reference samples and opposed to coreless winding methods. The research demonstrates the potential of coreless filament winding and inductively quantifies the positive influence of fiber pretension and core/die elements on the material properties at cost of decreased versatility, costs and design degrees of freedom.

Assessing and controlling the complex deformation behavior of textile reinforcements fabrics remains one of the major challenges in the production of fiber-reinforced plastics. In this paper, the draping of +45°/-45° biaxial non-crimp fabrics to a hemispherical shape is investigated with an eddy current imaging technique. After an automated draping process, the textiles are scanned with a robot-guided eddy current measurement system. From the resulting conductivity maps of the samples, the local yarn directions are extracted by image analysis and the paths of individual yarns are reconstructed for both the upper and the lower layer. Experiments are carried out for different forming speeds, blank holder forces and different non-crimp fabric parameters (stitch length, stitch type, stitch tension and yarn count). The influences of these parameters are compared and discussed, with the conclusion that blank holder forces have by far the most significant influence on the draping result. Sample experimental results are compared to results from an FEM draping simulation.

Natural muscles, that convert chemical energy derived from glucose into mechanical and thermal energy, are capable of performing complex movements. This natural muscle power was the only way to perform mechanical work in a targeted manner for millions of years. In the course of thousands of years of technical development, mankind has succeeded in harnessing various physical and chemical phenomena to drive specific mechanical processes. Wind and water power, steam and combustion engines or electric motors are just a few examples. However, in order to make the diversity and flexibility of natural motion patterns usable for machines, attempts have been made for many years to develop artificial muscles. These man-made smart materials or structures are able to react to environmental conditions by significantly changing their shape or size. For the design of effective artificial muscles that closely resemble the natural original, the usage of textile technology offers great advantages. By means of weaving, individual actuators can be parallelized, which enables the transmission of greater forces. By knitting the maximum stretching performance can be enhanced by combining the intrinsic stretching capacity of the actuators with the structural-geometric stretching capacity of the fabric. Furthermore textile production techniques are well suited for the requirement-specific, individual placement of actuators in order to achieve the optimal geometry for the respective needs in every load case. Ongoing technical development has created fiber based and non-fibrous artificial muscles that are capable of mimicking and even out-performing their biological prodigy. Meanwhile, a large number of partly similar, but also very different functional principles and configurations were developed, each with its own specific characteristics. This paper provides an overview of the relevant and most promising technical approaches for realizing artificial muscles, classifies them to specific material types and explains the mechanisms used as well as the possible textile applications.

This contribution will introduce carbon-reinforced concrete components (so-called carbon concrete composites, or C3) with sensor functionalities for innovative building envelopes. For a continuous in situ structural monitoring, these textile-reinforced concrete components are equipped with textile sensor networks consisting of resistive carbon fiber sensors (CFSs), which are integrated into the carbon fiber non-crimp fabrics of the concrete reinforcement by multiaxial warp-knitting. The in situ CFSs, consisting of 1 k or 50 k carbon fiber roving with added staple fiber/multifilament dielectric cladding, are later integral to the load-distributing elements of the concrete component, and elongations within these are easy to record with good correlation to ohmic resistance changes. Gage factors of k = 0.52–1.23 at linearity deviations of ALin = 4.0–8.7% are feasible. This allows a monitoring of C3 building envelopes for structural mechanical changes caused by physical changes within the component through mechanical or thermal loads or deformation and cracks.

Fiber reinforced plastics are being used as different niche products in automotive, aerospace and plant engineering industries due to their lightweight potential and superior mechanical properties in comparison with traditionally used materials. Using structurally integrated actuators, single-axis and joint free adaptive fiber reinforced plastic components can be realized. In this work, the development of adaptive pleated fiber reinforced plastics based on shape memory alloys is reported. Furthermore, simulation supported deformation behavior of developed samples is investigated by varying the pleat height, pleat thickness and the spacing between two pleats. The deformation behavior of the adaptive pleated fiber reinforced plastics predominantly depends on the pleat height and spacing between two pleats.