Papers by Keyword: Carbon Fabric

Abstract: To shield re-entry spacecraft from the extreme heat experienced during hypersonic flight through a planet's or the earth's atmosphere, thermal protection systems (TPS) were developed. This work involved the fabrication of composites using a polyacrylonitrile (PAN) based carbon fabric (Cf)-phenolic resin matrix (PR) modified with different weight percentages (wt.%) of silicon carbide (SiC), namely 0 wt.% (Cf/PR), 1wt.%, 3wt.%, and 5wt.%. The composites were prepared using the hydraulic hot press method. The manufactured composites were analyzed for their thermal conductivity and resistance to ablation using an oxyacetylene torch test. Furthermore, the ablated composites underwent X-ray diffraction (XRD), revealing a SiO₂ compound layer on the ablated composite surface. The experimental results demonstrated that the Cf/PR composites modified with 3wt.% of SiC exhibited superior characteristics. The composites consist of 3wt.% Cf/PR-SiC exhibited a thermal conductivity value of 0.57 W/m K. Additionally, these composites showed a noticeable decrease in the mass ablation rate (MAR) at 0.0052 mm/sec and linear ablation rates (LAR) at 0.025061 gm/sec. This study proposed an effective way to improve the thermal and ablation characteristics of TPS materials.

Abstract: In recent years, wearable heaters have attracted widespread attention for applications in personal heating systems and healthcare management, such as thermotherapy of textiles/clothing. In addition, flexible gas sensors are important components of wearable electronic devices used for human safety and healthcare applications. However, the current low flexibility and poor stability of the materials limit their use. In this paper, among various textile materials, the carbon fabric based high-efficiency flexible heater with its own excellent conductivity, which does not contain additives from the manufacturing state, and a sensor using the same. In order to evaluate the performance of the heater, the heating temperature and power according to the applied voltage were analyzed. Also, the temperature distribution of the carbon fabric was observed using a thermal camera. The highly flexible fabric heater is based on a uniformly interconnected carbon fiber network that efficiently and quickly heats the heater with low input power. In addition, it presents a new carbon fabric gas sensor composed of pure carbon fiber itself without additives. The carbon fabric shows a sensitive response to NO₂ (24.4%@5ppm) at room temperature, and with an extreme bending radius of 3mm, it shows excellent mechanical reliability against repeated deformations over 1,000 bending cycles. The carbon fabric sensors are extremely flexible and durable even after bending, providing a stable resistance to the sensor base material. The results could be attractive to development of flexible, room temperature operable fabric based wearable gas sensing platforms.

Abstract: Nowadays, FRCM (Fibre Reinforced Cementitious Matrix) systems are highly attractive for the building materials market; thus, their optimization and development cover an essential role. This work points out the chemical and physical parameters influencing the carbon-FRCM mechanical behaviour. Three different FRCMs composed of commercially available carbon fabric and different inorganic matrices are involved. Matrices are specifically developed to enhance the adhesion with the fabric and differ in organic additive used. Moreover, different fabric geometry (twisted and untwisted) and fibre coatings are considered: micro-silica, fine silica aggregate and medium-size silica aggregate. A new shear test setup is designed to obtain an inexpensive characterization method and employs traditional mechanical tests. Morphological and compositional analyses were performed on the surface fractures. On equal reinforcement typology, significant improvements in shear strength are promoted by organic additives and fabric coatings. Also, pull-out test displays that the twisted bundle promoted the fibre-to-matrix adhesion and remarkably modified the sample failure mechanism compared to the untwisted one. Finally, the FRCM mechanical performance is primarily influenced by mechanical adhesion contribution that might be increased by adopting simple geometrical choices or fabric surface treatments.

Abstract: Fiber-reinforced composite materials are increasingly present in areas such as automotive, aeronautics, defense, sport, used due to their special mechanical characteristics and very good behavior under heavy working conditions. New mold design techniques (such as 3D printing technologies), processing (such as the use of robotic technologies), open new opportunities for future challenges. This paper represents research on analysis techniques for the design of composite materials products made of fiber-reinforced, research on the use of devices with feedback loop for mechanical cutting technologies, which allow intelligent dynamic adjustment of the processing regimes, analysis of manufacturing technologies used as unconventional processes for the implementation of inclusion components, economic judgments on advantages, disadvantages of the techniques and methods used.

Abstract: Low velocity impact strength of the fabric reinforced geocomposite has investigated in this article. Various fabrics such as carbon and E-glass were considered for reinforcement in geopolymer matrix. The primary two parameters such as low velocity, impact damage modes are explained on the E-glass and carbon based fabric geocomposite. The onset mode of damage to failure mode is examined through C-scan analysis. The quality of the composite is observed using c-scan with acoustic vibration mode of sensor before and after impact test. Then the effect of fabric and matrix on the impact behaviour is discussed. Residual strength of the composite is measured to determine post impact behaviour. It has been observed that resistance properties of E-glass reinforced composite is better than carbon fabric reinforced composite.

Abstract: This paper discusses numerical modeling of strengthened masonry pillars. The main aim of the article is to study a usability of the proposed numerical models for evaluation of behavior of strengthened pillars. Maximum stresses are evaluated in order to identify the possible masonry damage initiation. The paper mainly discusses 2D numerical models of pillars in several alternatives. References to 3D modeling are also given. The in-house developed software uFEM is used for most of the computations..

Abstract: This experimental study is focused on identification of tribological mechanisms acting during forming of polymer composites. The range of relevant processes includes fibre placement, tape lay-up, moulding, draping, and RTM. Two types of tribological experiments, relying both on simultaneous application of compression and shear loadings, are carried out. Firstly, model macromechanical tests are undertaken on plastic rods of millimetric diameter immersed in a viscous liquid, representing composite fibres and matrix, respectively. By careful simulation of forming conditions, this experiment helps to identify the friction phenomena occurring in real composites. On the other hand, the micromechanics of forming processes is studied through a microscopic experiment on real carbon fabric. This material is clamped between two glass plates and pulled in opposing directions in the plane of the fabric. It is hypothesized that the evolution of contact area due to shearing that can be measured in this experiment is an essential feature of the tribology of forming processes, a topic which hitherto has not been investigated.

Abstract: This paper presents a fundamental study of processing, morphologies, properties, and applications of a novel non-woven nanopaper based on carbon nanofibers (CNFs). Unique material formulations were developed to tailor the non-woven nanopaper to specific engineering applications. The non-woven nanopaper was made from a variety of nanomaterials (e.g. carbon nanotubes, carbon nanofibers, graphene, nanoclay, nickel nanostrands, POSS, etc.) with tailored nanostructures by precisely controlling composition, dispersion, functionalization, orientation, porosity, and thickness during the vacuum infiltration, pressure infiltration, or spray/infiltration process. The polymer matrix was impregnated into the stacked nanopapers to form multi-layered laminated composites. Such non-woven nanopaper based composites were designed and fabricated to achieve high energy dissipation capability for vibrational damping, high thermal conductivity and thermal stability for fire retardancy, ultra-high electrical conductivity and current-carrying capacity for lightning strike protection, and electro-actuation of shape memory polymer composites.

Abstract: Fiber reinforced polymer composites are generally known to possess high strength and attractive wear resistance in dry sliding conditions. The behaviour of such composites performing in abrasive wear situations needs a proper understanding. Hence, in the present work of the three-body abrasive wear behaviour of two dimensional stitched carbon fabric, E-glass woven fabric and three dimensional E-glass woven fabric reinforced vinyl ester composites was investigated. Three-body abrasive wear tests were conducted using rubber wheel abrasion tester (RWAT) under different abrading distances at two loads, wherein the wear volume loss were found to increase and that of specific wear rate decrease. The results indicate that the type of fabric in vinyl ester have a significant influence on wear under varied abrading distance/loads. Further, it was found that carbon fabric reinforced vinyl ester composite exhibited lower wear rate compared to E-glass woven fabric reinforced vinyl ester composites. The worn surface features, as examined through scanning electron microscope (SEM), show higher levels of broken glass fiber in two dimensional glass woven fabric reinforced vinyl ester composite compared to carbon fabric and three dimensional glass fabric reinforced vinyl ester composites.

Abstract: The ablation properties, thermal resistance and micro structural behavior of the phenolic resin (Resole) composites have been investigated in this research. Different materials, such as carbon fabrics, glass fabrics, also silica and zirconia powders have been used as reinforcements for synthesis of the composites. The specimens were prepared with three sets of compositions. The first set was produced with 37.5 wt% of Resole and 62.5 wt% of reinforcements. Another set of specimens were produced with 40wt% Resole, 40 wt% of silica and 20 wt% of zirconia. Also to achieve high insulation index in Resole/carbon fabrics composites a thin film of zirconia coated at the back side of the specimens. To explore the ablation characteristics of the composites in terms of insulation index, erosion rate and microscopic pattern of ablation, an oxyacetylene torch flame with heat flux of 10 Mw/m2 at approximately 2800°C was used. The ablation behavior and microstructure of the burnt-through specimens were also observed, using scanning electron microscopy. It was found from ablation test that the erosion rates of the Resole/carbon fabric specimens are 20% lower than the other specimens. Additionally the high insulation index of the Resole/carbon fabrics coated with zirconia indicates that these composites are the best ablative materials in the present study. It has been also reported that those specimens filled with zirconia have the highest insulation index. Although the erosion rate of the Resole/silica composites were 20% higher than the Resole/glass fabrics, but a 5mm depth hole (from 10 mm thickness of the whole specimen) was seen at the center of the Resole/glass Fabric specimens. SEM observations show that proper adhesion between reinforcements and matrix is important to achieve improved ablative properties, it was also reported many changes in diameter, shape and the surface of the carbon fibers through the ablated area. These changes can be reduced from surface to back side of the specimens.