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In this work, fiber-reinforced laminates for the envelope (hull) of high-altitude airships were developed using a novel design concept utilizing ethylene vinyl alcohol (EVOH) as the adhesive compon...

Over the past few decades, ecological concerns resulted in an interest in using natural fibers such as flax and hemp as a reinforcement in composite materials. However, the inherent variability of ...

Recent advancements in 3D printing involve reinforcing the polymer matrix with high-strength fibers offer improved mechanical properties over unreinforced polymeric materials. The fiber-reinforceme...

The present research investigated previously unexplored attributes of 3D printed continuous fiberglass reinforced Nylon composites, Drop-weight and pendulum (Charpy and Izod) impact resistance incl...

The effect of different concentrations of Hydroperm T (a hydrophilic surface finishes) on the electrostatic charging and decay properties of filament polyester fabrics, has been investigate...

The results of a study of charge generation and decay for range of woven fabrics from ring spun cotton yarns, ring spun polyester yarns, and flat continuous filament polyester yarns treated with topical finishes are reported. The topical finishes include commercially available ionic antistatic finishes, one commercially available hydrophilic finish, and a new experimental moisture management finish. The fabrics were rubbed against surface of steel and Polytetrafluoroethylene (PTFE; Teflon®) and their frictional electrification and charge dissipation were monitored. It is shown that fabrics from cotton have a more rapid inherent charge decay than fabrics from polyester. Ionic antistatic finishes are shown to be effective in reducing charge generation and promoting charge decay and this is particularly true for the fabrics made from filament polyester. When commercially available and experimental hydrophilic finishes were applied on fabrics made from filament polyester, less charge was generated and...

Tururi (Manicaria saccifera Gaertn.) is a natural fibrous mesh which protects the fruits of the Amazon Ubucu palm tree. This research targets developing natural fiber composites from Tururi...

Development of three-dimensional (3D) weaving technology introduced new and enhanced features to the 2D weaving technology. 3D Orthogonal Woven (3DOW) preforms have a through-thickness yarn component that significantly enhances the out-of-plane properties and delamination resistance. In this study, a range of 3DOW E-glass preforms were woven using 3D weaving technology and then converted into composites, using vacuum assisted resin transfer molding technology. The composite samples had varying Z to Y-yarn/ layer ratio, the objective is to study the effect of changing the Z to Y-yarn/ layer ratio on the in-plane and out-of-plane mechanical properties. The study concludes that changing the amount of Z-yarn in the structure has negligible effect on the tensile (in-plane), yet, it has a significant effect on the drop weight impact properties (out-of-plane). Moreover, it had a strong effect on the failure mechanisms, and as the amount of Z-yarn is reduced, delamination became more significant.

Over the past few decades, there have been an increasing interest in woven preforms as a reinforcement for composites. The invention of 3D Orthogonal Weaving (3DOW) technology introduced new and en...

E-textiles contain electrically conductive elements and electronic devices that are integrated in textile substrate. Wearable e-textiles are expected to perform like textiles in terms of breathability, conformability, and comfort despite the presence of the electrically conductive elements and electronics. E-textiles are also expected to provide reliable data and signal processing like electronic devices while they are subjected to normal wear and tear under different environmental conditions. The goal of this research was to investigate the electrical integrity of e-textiles while they are subjected to environmental conditions. Different woven samples of electronic-improved outer tactical vest with two narrow conductive traces woven in the warp direction were subjected to range of temperatures and humidity, including extreme conditions. The effects of formation parameters (e-yarn type, number of e-yarns/trace, and weldability), temperature, and humidity on the integrity of the e-textiles were stu...

In our previous publications, the response of perfluorinated (PF) graded index (GI) POFs (62.5/750, 62.5/490m) to bending, tensile loading, and cyclic loading was investigated. The results showed that Cytop-1 (62.5/750m) was more appropriate to be used as an optical fiber sensor for automotive seat occupancy sensing relative to Cytop-2 (62.5/490m). In this study, a textile-based optical fiber sensor was designed and the effect of automotive seat covering including face material and foam backing on a sensor's performance was analyzed. The pressure interval under which the proposed POF sensor design could perform well was found to be between 0.18 and 0.21N/cm(2), where PF GI POF (62.5/750m) was used as the POF material. The responses of the sensor in this interval were observed to be accurate and reproducible. The face fabric structure and the thickness of foam backing were not found to be significant factors to change the sensor response. Artificial neural network (ANN) was used for data analysis, and Qwiknet (version 2.23) software was used to develop ANNs. According to the results of Qwiknet, the prediction performances for training and testing data-sets were 75 and 83.33%, respectively.

The goal of this research aimed to develop an accurate and reproducible textile-based optical fiber sensor for automotive seat occupancy. In our previous publication, the response of perfluorinated (PF) graded index (GI) polymer optical fibers (POFs) (62.5/750 and 62.5/490m) to bending and tensile loading was investigated. In this study, the response of the PF GI POFs to cyclic loading was investigated. The repeated loading and unloading the POF sensor would experience due to car vibrations and multiple uses by seat occupants, might cause fatigue failure to the POF sensor. The results showed that the Cytop-1 did not show any permanent deformation up to 500 cycles at strain rates 4 and 60mm/min at a gage length of 76.2mm in its elastic sensitive strain region. The Cytop-2 showed permanent deformation at 3.5% strain after 500 cycles at a gage length of 76.2mm. Thus, the Cytop-1 was found out to be more appropriate to be used as an optical fiber sensor for automotive seat occupancy sensing relative to the Cytop-2. In this study, a theoretical approach of the behavior of PF GI POF to cyclic loading was also provided.

Super pressure balloons (SPBs) are used by the National Aeronautics and Space Administration (NASA) for ultra-long duration ballooning (ULDB) missions which carry various scientific explorations to support space and earth sciences research activities. The resistance to photo-degradation of load-bearing braided tendons of SPBs is critical to the success of ULDB missions. Recognizing the critical need to improve UV and visible light (UV–Vis) protective performance of p-phenylene-2, 6-benzobisoxazole (PBO) braids, North Carolina State University and NASA's Balloon Program collaborated to investigate the effectiveness of sheath extrusion method in improving the UV–Vis resistance of tendons. This study included two PBO tendon types – 48,000 (48k) denier tendons and 72,000 (72k) denier tendons. Using a sheath extrusion method, the tendons were covered with UV protective sheath of low-density polyethylene containing two types of UV inhibitors – TiO2 rutile nanoparticles and PolyOne PE White CC®. Bare and sheathe...

Through the thickness mechanical properties of composites have been improved with the advance of 3D woven preforms incorporating through-thickness reinforcement element compared to 3D woven composites from stack of 2D fabrics. In this study, a generalized geometric model considering non-jammed and jammed constructions of 3D orthogonal woven preforms from spun yarns was developed to predict fiber volume fraction (FVF) of structure constituents, preform thickness, preform areal density, and minimum thread spacing (x-, y-, and z-yarn spacing) to achieve jammed construction in terms of weave factor, number of layers, and constituents’ variables (y- and z-yarn sequence, linear densities, packing factor, and fiber volumetric density). Numerical results are presented to demonstrate the generalized model potential as a design tool to achieve broad range of constituents FVF that controls composite performance.

Silica optical fibres (SOF) are established for the use of communicating digital data and numerous applications including structure health monitoring. However, SOFs exhibit drawbacks such as brittleness, low strain and signal attenuation due to bending. These drawbacks limit the use of SOF as embedded sensors for monitoring composite structures’ internal health. Unlike SOFs, the relatively newly developed polymer optical fibres (POF) do not possess such drawbacks and they are able to monitor the health of fibre-based composite structures. Bending in optical fibres is a major concern since this causes signal attenuation at bending points. Integrating optical fibres into a woven preform requires bending because of the crimping that occurs as a result of weave interlacing. The main objective of this research was to evaluate the effect of the macrobending of optical fibres on signal power integrity. The goal is to design optical fibre sensors embedded in woven preforms that have high sensitivity for monitorin...

Nylon and polypropylene surfaces were treated with three different finishes (nonionic, cationic, and anionic) at four different solution concentrations (weight percentage of active finish to solution), 0.025%, 0.05%, 0.075%, and 0.1%. Contact electrification tests showed that charge accumulated on polypropylene decreased as the concentration of nonionic and anionic solutions increased, and charge could be controlled when the concentration reached 0.1%. The same effect was realized when the concentration of the cationic solution was only 0.025%. No contact charging was observed on nylon after treating with any solutions. Rubbing electrification (tribo‐charging) of nylon treated with the nonionic solution showed that charge decreased as the solution concentration increased, and no charge was observed as the solution concentration reached 0.1%. Furthermore, no tribo‐charging of nylon was observed at any level of the cationic or anionic agents applied to the surface.

The effect of relative rubbing speed on the tribo‐electrification between different continuous filament yarns and stainless steel “charging pins” was analysed. A modified linear tester, housed in an environmental room, was used to charge the yarn while transporting at desired speed and input tension. The yarn was rubbed against the charging pin, which was also rotated at different speeds. The yarn surface charge, yarn output tension and charging pin’s vibration were monitored in real time automatically. The results showed that for nylon yarn charge was minimized when the yarn/pin relative speed approached zero, regardless of the absolute rubbing speeds of yarn and pin. It was also found that, at the same relative speed, less charge was generated when a larger pin was used. For finish‐free nylon yarn, the charge was also minimized as the relative speed approaches zero; however, for finish‐free polyester yarn and finish‐free polypropylene yarn, the effect of relative rubbing speed on the electrification was...

The effect of environmental conditions (temperature and relative humidity) and contact conditions (yarn tension and speed) on static generation and dissipation of polyester flat continuous filament yarn, when rubbed against stainless steel was analyzed. A newly developed device, housed in an environmental room, was used to charge the yarn while moving under desired tension. The charge potentials were measured at two different positions in real time. These measurements and previously established exponential relationship permitted the calculation of the initial potential (at the generation point) and a ‘characteristic decay time’, which is a measure of static dissipation. Experimental data showed that temperature, humidity, yarn tension, and yarn speed have significant effects on static generation; while temperature, humidity, and yarn speed yielded statistically significant changes on static dissipation. Anomalous behavior of static charge when measured at a temperature of 35°C, provided a meaningful clue ...

An online yarn tension sensing and control device has been designed and developed. The system was specifically devised for use in a direct cabling machine, wherein yarn tension in the spindle or pot yarn is highly critical and dictates the uniformity of the cabled yarn. Since a balloon formed by the creel yarn always encompasses the pot yarn in a direct cabling machine, yarn tension measurement using a wired sensor is far-fetched. Accordingly, a wireless yarn tension sensor was developed to address this problem and perform online yarn tension measurement. The wireless sensor can be used as an active monitoring tool for measuring online yarn tension in both component yarns, while the closed loop control system replaces passive yarn brakes used in the current direct cabling machines and executes a control mechanism that can control yarn tension adaptively. The device uses Micro-Electro-Mechanical Systems (MEMS) technology with radio frequency (RF) transmission to effectively carry out dynamic online measure...

Hydroentanglement is a mechanical bonding process utilised to produce nonwoven fabrics. A web of loose fibres is put on a forming belt or perforated screen to form an integrated fabric with desired aesthetics by subjecting the web to multiple rows of fine high-pressure water jets. Mechanical performance of hydroentangled nonwovens is determined by the degree of the fibre entanglement, which depends on process parameters. This study presents the results of combined experimental and numerical investigation on the effects of the jet pressure and forming belt geometry on fibre entanglement. Extensive comparisons of simulations with experimental data are reported and analysed to give a clear understanding of the effect of fibreweb and forming belt properties on the critical jet pressure. The modelling results are in good correlation with experimental data for a wide range of jet pressures. The effect of the jet count per unit length on the degree of fibre entanglement is also investigated.

Dynamic electrostatic generation and dissipation on polymer surfaces are of great importance for materials such as yarns and films. To support fundamental research in this area, innovative devices and experimental techniques that can lead to a better understanding of these phenomena are of obvious academic and industrial interest. This paper reports the development of devices for testing the electrostatic generation/dissipation properties of polymer surfaces. These devices include a tester for assessing moving yarns, a high-resistance system to measure the yarn's linear resistance, a tester for evaluating stationary fabrics or films while rubbing against a moving surface and a contact charge tester for investigating charge generated by contacting of two surfaces. These devices enable the study of the influences of relative moving speed, yarn tension, electrostatic charge properties of yarns, as well as contact pressure, rubbing speed, number of rubbings or contacts on the static charge properties of films.

Hydroentanglement is a fast-growing process for manufacturing non-woven fabrics. In this process, multiple fine jets of highly pressurised water are directed towards a fibreweb composed initially of loose fibres, supported by the forming belt. The impact of the jets causes fibre entanglement in the fibreweb and produces an integrated fabric with desired aesthetics. It is important that, at the end of the process, the fibreweb could be easily separated from the forming wires. In this paper, the peeling force required for the separation of the hydroentangled fabric from the forming wires is measured experimentally. Numerical simulations of the hydroentanglement process are also carried out to predict the probability of fibres to be pushed in the knuckles of the forming wires. The fibres that get caught in the knuckles are mainly responsible for the peeling force of the fabric from the forming wires. The fibreweb is modelled as a porous layer, which is supported by forming wires. By correlating experimental ...

We developed a system to align fibres by using electrostatic forces to form fibreweb with desired fibre orientation. The purpose of developing such a system is to investigate an innovative mechanism of forming disc shape fibrewebs with engineered fibre orientation for the industrial fields such as carbon fibre reinforced brake discs and abrasive wheels for metal surface finishing. We provide computer models for simulating the process of transporting fibres in electrostatic field and laying them down to a fibre-collecting surface. The model reveals the effects of electrostatic field properties such as voltage and electrodes geometry on fibre orientation distribution. We also developed visualisation programmes to help display and analyse resultant data. Our experimental results and theoretical simulations are in a good agreement and show that the development of a new generation of non-woven fabrics with engineered fibre orientation distribution is achievable with the correct levels of the independent parame...

Research related to warp breaks has been limited to monitoring break frequency and the reason associated with breaks in order to improve warp yarn quality. While this approach led to improvement in weaving efficiency, warp breaks still represent a major problem, especially for today's high-speed weaving machines. Researchers have been trying to develop commercial automated systems to repair warp breaks with no success. The goal of this study is to explore inexpensive methods to detect warp breaks using nontraditional technique that would pave the way to automate warp break repair. To achieve the goal, a system that can detect warp breaks using MEMS accelerometers as sensors was developed for Jacquard weaving. The MEMS accelerometers were mounted on harness cords of a Jacquard tie. MEMS output acceleration signals components in the vertical and horizontal directions were analysed using time and frequency domains. The signals were acquired while warp ends are running and at the moment of intentiona...

(2004). FIBER-BASED ELECTRICAL AND OPTICAL DEVICES AND SYSTEMS. Textile Progress: Vol. 36, No. 2-3, pp. 1-84.

A model was developed to support a structured approach to the investment-decision process in the weaving industry. This model assists the initial investigation through an investment guide. It enabl...