Papers by Abdelfattah Seyam
Smart textiles: evaluation of optical fibres as embedded sensors for structure health monitoring of fibre reinforced composites
Journal of the Textile Institute, 2013
ABSTRACT Silica optical fibres (SOF) are established for the use of communicating digital data an... more ABSTRACT 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 monitoring the health of composite structures. Newly developed Graded Index Perfluorinated POF (GI-PF-POF) and two types of SOFs were evaluated in a three-point macrobending test bed using a laser light source. A systematic experimental design was executed to evaluate the optical fibres’ signal loss as a result of the bending radius, bending deflection and wrap angle of optical fibre around the middle rod of the test bed. The results showed that POF provides higher signal sensitivity and greater robustness against signal attenuation under bending when compared to SOF. The work also unveiled the bending radius of optical fibres at which minimum or no signal loss occurred. This finding is essential for designing embedded optical fibre sensors with high sensitivity.
The role of hydrophilic finishes in frictional electrification and charge decay of woven fabric from polyester
The Journal of The Textile Institute
International Nonwovens Journal
The main goal of this study is to investigate the performance behavior of hydroentangled nonwoven... more The main goal of this study is to investigate the performance behavior of hydroentangled nonwoven fabrics in terms of input water jet energy and fabric structural parameters (basis weight and fiber orientation). The input jet energy was varied by altering jet pressure, number of passes, process speed and fabric basis weight. To achieve the goal, two sets of trials, which had different jet pressures, process speeds, basis weights and number of passes, were executed to reveal the significance of these parameters in achieving high fabric tensile strength. Image analysis was used to determine the fiber orientation of the hydroentangled nonwoven fabrics to aid in understanding fabric performance behavior.
International Nonwovens Journal
The paper is reporting an extensive experimental investigation to optimize the processing of micr... more The paper is reporting an extensive experimental investigation to optimize the processing of microfibers on a flat top card. Carding parameters, type of fiber finish and their interactions were studied in terms of their impact on web quality. The web quality was determined by assessing the nep content and fiber breakage due to carding. Statistical analyses of the data indicate that fiber finish and processing parameters can be selected to minimize neps and fiber breakage during carding. Furthermore the investigation showed that there is a strong correlation between the incidents of neps and the increase in short fiber content during carding. An additional finding of this study is that the generation of neps was not uniform across the width of the carded web and is influenced by fiber load measured on the doffer in the cross machine direction.
Improving UV Resistance of Fibers: Idealized Computational Model Predicting the Distribution of UV Blocking Cylindrical Nanoparticles in Protective Polymeric Layer
Journal of Engineered Fibers and Fabrics
High strength fibers such as PBO and Kevlar are used to produce composites, bulletproof vests, te... more High strength fibers such as PBO and Kevlar are used to produce composites, bulletproof vests, tendons of giant scientific balloons, and other high performance products. These fibers, however, are known to degrade upon exposure to Ultraviolet (UV) radiation which causes premature failure of the end-products. Improving UV resistance of high strength fibers like PBO through methods such as adding UV inhibiting particles during filament spinning or dyeing/coating process is not only extremely difficult, but often fails to provide the adequate UV protection. As an alternative to conventional approaches, UV protection of high performance yarns/braids can be effectively achieved by covering them with a polymeric sheath containing dispersed UV inhibiting nanoparticles. In this work, a computational model was developed to optimize critical factors such as thickness (weight) of the protective sheath and the amount of UV blockers for a given particle size, which influence the UV protective ef...
Journal of Engineered Fibers and Fabrics
The electrostatic charge on nylon, polypropylene (PP), and polytetrafluoroethylene (PTFE) after r... more The electrostatic charge on nylon, polypropylene (PP), and polytetrafluoroethylene (PTFE) after rubbing against stainless steel and against each other was examined using a newly developed rubbing device with automated features. It is observed that the charge generated on PTFE and PP increases as the contact force increases, while the charge generated on nylon is not affected by the contact force. It is also found that the charge generated on PTFE and nylon due to friction is more than that due to repeated contacts and separations, however, this difference was not observed on PP. Furthermore, the charge generated on these three polymers is not affected by the rubbing speed at the levels of 27, 47, 95 mm/min. In addition, the triboelectric series of these three polymers and stainless steel is investigated by rubbing against each other.
Journal of Engineered Fibers and Fabrics
analyses and computer modeling of the el web forming process provide better insights in method an... more analyses and computer modeling of the el web forming process provide better insights in method and serve as a powerful tool for en development. Numerical results were obt presented for a range of processing variable
Journal of Engineered Fibers and Fabrics
In hydroentanglement process, very fine water jets with high pressure impinge on the fiberweb, wh... more In hydroentanglement process, very fine water jets with high pressure impinge on the fiberweb, which is supported by forming wires. The impact of the jets causes fiber entanglement in the fiberweb and produces an integrated fabric with desired performance, texture, and appearance similar to the forming wires. It is important that at the end of the process, the fiberweb can be easily separated from the forming wires. In this paper, the force of peeling required for the separation of the wet, hydroentangled fabric from the forming wires is measured experimentally. A set of experimental trials was conducted to investigate the effects of the jet pressure, fiberweb basis weight, and forming wires mesh size on the peeling force. Visualizing fibers caught in the knuckles of the forming wires under magnification reveals physical mechanisms leading to the formation of the peeling force.
International Nonwovens Journal
In previous publication, the influence of process parameters on the fiber orientation of the melt... more In previous publication, the influence of process parameters on the fiber orientation of the meltblown web was evaluated [4]. The meltblown webs were formed using Robotic Fiber Assembly and Control System (RFACS), which is described in previous publications [3, 4]. In this paper, parametric studies evaluating the effect of polymer throughput rate, attenuating air pressure and temperature, and die temperature, on fiber diameter distributions of meltblown webs from polypropylene produced by RFACS are reported. Fiber diameters were determined by analyzing fabric images obtained through scanning electron microscopy (SEM). Under the specific conditions explored, the fraction of fibers of diameter smaller than 10 microns (µm) can increase by 72% with a 7.9 x 10-2 g/min/hole (82%) reduction in throughput. A 54% increase of the same can be observed with a 2.8 bar (400%) increase in attenuating air pressure. A change of 45ºC (16 %) in air temperature is shown not to significantly affect fiber diameters produced, while an increase of 67ºC (26%) in die temperatures can result in an increase of 17% in the fraction of fibers of diameter smaller than 10µm. All fiber diameter distributions are shown to be unique to the condition evaluated as no overlap across distributions for changes in a given parameter is observed. Further fiber fraction smaller than 10 µm data is also shown to be unique to each parameter evaluated.
Journal of Engineered Fibers and Fabrics
Mechanical performance of hydroentangled nonwovens is determined by the degree of the fiber entan... more Mechanical performance of hydroentangled nonwovens is determined by the degree of the fiber entanglement, which depends on parameters of the fibers, fiberweb, forming surface, water jet and the process speed. This paper develops a computational fluid dynamics model of the hydroentanglement process. Extensive comparison with experimental data showed that the degree of fiber entanglement is linearly related to flow vorticity in the fiberweb, which is induced by impinging water jets. The fiberweb is modeled as a porous material of uniform porosity and the actual geometry of forming wires is accounted for in the model. Simulation results are compared with experimental data for a Perfojet ® sleeve and four woven forming surfaces. Additionally, the model is used to predict the effect of fiberweb thickness on the degree of fiber entanglement for different forming surfaces.
Polymer optical fibers integrated directly into 3D orthogonal woven composites for sensing
Smart Materials and Structures, 2015
ABSTRACT This study demonstrates that standard polymer optical fibers (POF) can be directly integ... more ABSTRACT This study demonstrates that standard polymer optical fibers (POF) can be directly integrated into composites from 3D orthogonal woven preforms during the weaving process and then serve as in-situ sensors to detect damage due to bending or impact loads. Different composite samples with embedded POF were fabricated of 3D orthogonal woven composites with different parameters namely number of y-/x-layers and x-yarn density. The signal of POF was not affected significantly by the preform structure. During application of resin using VARTM technique, significant drop in backscattering level was observed due to pressure caused by vacuum on the embedded POF. Measurements of POF signal while in the final composites after resin cure indicated that the backscattering level almost returned to the original level of un-embedded POF. The POF responded to application of bending and impact loads to the composite with a reduction in the backscattering level. The backscattering level almost returned back to its original level after removing the bending load until damage was present in the composite. Similar behavior occurred due to impact events. As the POF itself is used as the sensor and can be integrated throughout the composite, large sections of future 3D woven composite structures could be monitored without the need for specialized sensors or complex instrumentation.
“Theory of Forming Fiberwebs with Controlled Fiber Orientation Using Electrostatic Field”
“Development of an Innovative Electrostatic Fiber Web Formation: Fiber Movement Simulation”
Fabric and yarn structures for improving signal integrity in fabric-based electrical circuits
On the use of robotics for melt-blowing to form shaped/molded fabric structures
Proceedings 2000 Icra Millennium Conference Ieee International Conference on Robotics and Automation Symposia Proceedings, 2000
This paper presents an overview of research on the production of nonwoven and tailored 3D structu... more This paper presents an overview of research on the production of nonwoven and tailored 3D structures for protective garments (such as those worn by fire fighters) using robotics and meltblown technology. In particular, the integration of robotics and a small-scale melt-blowing unit is discussed. This paper develops the framework and general motivation for the overall study and describes in detail
Protective clothing system for cold weather
Journal of Textile and Apparel Technology and Management, Apr 2, 2013
This paper critically reviews previous work in the field of electrospinning of biopolymers and an... more This paper critically reviews previous work in the field of electrospinning of biopolymers and antimicrobial polymeric materials, and investigates the potential of Soy Protein fibers in electrospinning. Biomaterials have since long been the popular choice for fabricating medical textiles or scaffolding materials owing to their biocompatibility, intrinsic anti-microbial activity and low immunogenicity. Even among biopolymers, plant-based protein fibers are more preferred than carbohydrates. Electrospinning of such biopolymers into nanofibers provides one with advantages of properties such as relatively very high porosity, pore interconnectivity, drugcarrying capacity and close similarity to the extra-cellular matrix in the body. Soy protein fibers are envisioned to be an excellent component in fiber spinning mixtures. Mixing of Soy protein with other spinnable polymers such as cellulose, PEO, PVA and chitosan is proposed. Woundhealing is an important application for these materials. The emphasis needs to be on the functionality of such materials, more than mechanical strength which is not a vital necessity for class II medical devices such as wound dressings. A comparatively uninvestigated area is the potential of soy protein fibers for such uses.
Improving uv resistance of high strength fibers used in large scientific balloons
ABSTRACT For the last three decades, NASA has been involved in the development of giant balloons ... more ABSTRACT For the last three decades, NASA has been involved in the development of giant balloons that are capable of lifting heavy payloads of equipment (such as large telescopes and scientific instruments) to the upper atmosphere. While the use of such balloons has led to scientific discoveries, the demand for competitive science payloads and observational programs continues to rise. The NASA Balloon Program Office has entered a new phase of research to develop an Ultra Long Duration Balloon (ULDB) that will lift payloads of up to 3,600 kg to altitudes of up to 40 km. The flight duration is targeted to ranges between 30 to 100 days. Attaining these target durations requires the development of a super-pressure balloon design. The use of textile structures have already been established in these missions in the form of high strength tendons essential for the super pressure pumpkin design. Unfortunately, high strength fibers lose significant strength upon exposure to Ultra Violet (UV) radiation. Such UV degradation poses a serious challenge for the development of the ULDB. To improve the mission performance of the ULDB, new methods for protecting the tendons from the environmental effects need to be developed. NASA and NC State University College of Textiles are undertaking a research program to address these issues. Four tracks have been identified to prepare finishes that are believed to enhance the resistance of high strength fibers to UV. These tracks are: (a) self-polymerizing, (b) diffusion application, (c) polymer-filled with 30-40% UV absorber, and (d) combination of dyeing plus surface application. Four high performance fibers have been selected for this research investigation. These are Vectran (trademark), Spectra (trademark), Kevlar (trademark) and, PBO (Zylon (trademark)). This work will address the current progress of evaluating the performance of the UV finishes. This will be accomplished by comparing the tensile properties (strength, breaking elongation, modulus, etc) of untreated, unexposed to UV fibers; untreated exposed to UV fibers; and treated exposed to UV fibers.
Electrostatic Fiberweb Formation with controlled Fiber Orientation Distribution: Theoretical Analysis
Journal of Engineered Fibers and Fabrics, 2007
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Papers by Abdelfattah Seyam