Fiber Shape Research Articles

High-Velocity Impact Studies on Scaled Leading Edges of Horizontal Tail with Smart Composite Layers

Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabricated. The parameters like bird dimension and energy requirements are accordingly scaled to conduct the bird strike tests. Two leading-edge components have been prepared, namely one with AL 2024-T3 aluminium alloy and the other specimen of the same dimension and material, additionally having GF-SMP composite layers inside the metallic leading edge, in order to enhance its impact resistance. Bird strike experiments are performed on both the specimens, impacting at the centre of the leading edge in the nose tip region with an impact velocity of 115 m/s. The test component is instrumented with linear post-yield strain gauges on the top side and the PZT sensors on the bottom. Furthermore, the impact scenario is monitored using a high-speed camera at 7000 fps. The bird strike event is simulated by an equation of state model, in which the mass of the bird is idealized using smooth particle hydrodynamics element in PAMCRASH? explicit solver. The strain magnitude and its pattern including time duration are found to be in a good correlation between test and simulation. Key metrics are evaluated to devise an SHM scheme for the load and impact event monitoring using strain gauges and PZT sensors. GF-SMP layers have improved the impact resistance of the aluminium leading edge which is certainly encouraging towards finding a novel solution for the high-velocity impact.

Shear-induced migration of confined flexible fibers.

We report an experimental study of the shear-induced migration of flexible fibers in suspensions confined between two parallel plates. Non-Brownian fiber suspensions are imaged in a rheo-microscopy setup, where the top and the bottom plates counter-rotate and create a Couette flow. Initially, the fibers are near the bottom plate due to sedimentation. Under shear, the fibers move with the flow and migrate towards the center plane between the two walls. Statistical properties of the fibers, such as the mean values of the positions, orientations, and end-to-end lengths of the fibers, are used to characterize the behaviors of the fibers. A dimensionless parameter Λeff, which compares the hydrodynamic shear stress and the fiber stiffness, is used to analyze the effective flexibility of the fibers. The observations show that the fibers that are more likely to bend exhibit faster migration. As Λeff increases (softer fibers and stronger shear stresses), the fibers tend to align in the flow direction and the motions of the fibers transition from tumbling and rolling to bending. The bending fibers drift away from the walls to the center plane. Further increasing Λeff leads to more coiled fiber shapes, and the bending is more frequent and with larger magnitudes, which leads to more rapid migration towards the center. Different behaviors of the fibers are quantified with Λeff, and the structures and the dynamics of the fibers are correlated with the migration.

Microplastic contamination in Indonesian anchovies from fourteen locations

Abstract. Ningrum EW, Patria MP. 2021. Microplastic contamination in Indonesian anchovies from fourteen locations. Biodiversitas 23: 125-134. Microplastics in seawater can enter into the food chain of pelagic fish with subsurface foraging behavior such as anchovies (Stolephorus spp.). Anchovies are valuable commercial fish with high market demand. Hence, measuring potential marine pollutants in these fish is needed. Microplastics as marine contaminants are reportedly more dangerous if they occur together with other contaminants such as trace metals. This research aims to detect microplastic contaminants in anchovies caught in the Indonesia Sea. This research compared between the microplastic contamination on anchovies from 14 harbors: 6 in Western Indonesia (Meulaboh, Krui, Pangkalpinang, Muara Angke, Karimunjawa, and Sidoarjo) and 8 in Eastern Indonesia (Manado, Mamuju, Makassar, Kendari, Ambon, Sorong, Fakfak, and Waingapu). We isolated the digestive tracts of anchovies and measured their length and dry weight. The organic materials were digested with NaOH and a technical-grade sodium Laureth sulfate (SLES) solution approximately one week after collection. Microplastics were observed using a microscope and confirmed with Fourier transform infrared spectroscopy (FTIR). We found that most microplastic contaminants in anchovies were in fiber and film shapes. The majority of the sizes ranged from 50-500 ?m, followed by a range of 20-50 ?m. Microplastics were surprisingly high in samples from Mamuju (688±1.15 MPs idv-1) and Krui (645±7.02 MPs idv-1), higher than any contaminated biota ever reported for anchovies. As reported, anchovies from the Indonesia Sea are contaminated by microplastics. Moreover, human exposure to microplastic contaminants is possible and may affect consumer health in long-term exposure.

Type and Distribution of Microplastics in Beach Sediment along the Coast of the Eastern Gulf of Thailand

In the oceans and coasts, plastic waste poses a global threat to biodiversity. This study examined the types and distribution of microplastics in beach sediment along the coast of the eastern Gulf of Thailand in March 2018 (northeast monsoon = dry season) and July 2018 (southwest monsoon = rainy season). Microplastic samples were collected from six stations including Koh Khramyai Beach (Chonburi Province), Koh Mannai Beach (Rayong Province), Chao Lao Beach (Chanthaburi Province, 3 stations), and Ploy Dang Beach (Trat Province). The results showed that the highest average abundances of microplastics in March and July were at Koh Mannai Beach (1698 pieces/m2) and Koh Khramyai Beach (799 pieces/m2), respectively. However, no microplastics were found at Ploy Dang Beach in July. According to polymer-type identification using an FTIR spectrometer, 17 polymer types were found in this study. Polyethylene terephthalate (PET = 39.6%) and polyamide (PA = 22.8%) were the polymer types found in the highest proportions in March and July, respectively. In addition, the fiber shape and transparent color of microplastics were found to be the most abundant.

Tunable terahertz Dirac-semimetal hybrid plasmonic waveguides

Based on the Dirac semimetals (DSM) modified hybrid plasmonic waveguides, the tunable propagation properties have been systematical investigated by using the finite element method in the THz region, including the influences of structural parameters, the shape of dielectric fiber and Fermi levels of DSM layers. The results show that as the operation frequency increases, the real part of propagation constant increases, and the loss shows a peak. The shape of dielectric fiber (the elliptical structural parameter δ) affects the propagation property obviously, as the structural parameter decreases, the confinement and figure of merit increase, the loss reduces. With the increase of Fermi level of DSM layer, the imaginary part of propagation constant decreases, the modulation depth of loss is more than 95% if the Fermi level changes in the range of 0.01-0.15 eV. In addition, as the permittivity of dielectric material filling in the slit increases, the mode confinement and loss increases, FOM decreases. The results are very helpful to understand the tunable mechanisms of hybrid waveguides and design novel plasmonic devices in the future, e.g. modulators, filters, lasers and resonators.

Dynamic compressive behaviour of recycled tyre steel fibre reinforced concrete

This paper presents a systematic experimental study on dynamic compressive behaviour of recycled tyre steel fibre (RTSF) reinforced concrete. The use of RTSF can not only enhance the mechanical properties and sustainability of cementitious materials but also reduce the environmental impact of waste tyres. A series of tests were conducted to investigate the effect of RTSF content (0.5%, 0.75%, 1.0% and 1.25%) on workability, air content and compressive strength of concrete as well as the dynamic compressive behaviour under various impact velocities (35, 55, 75, 95, 110 and 125 s−1). For comparisons, plain concrete without fibre and concrete reinforced with 1.0% industrial steel fibre (ISF) were regarded as the reference mixtures. The split Hopkinson pressure bar (SHPB) was adopted to study the dynamic failure pattern, dynamic compressive strength, dynamic increase factor (DIF), energy dissipation and toughening mechanism. Results indicate that with increasing RTSF content, the slump of concrete was reduced while its air content was increased. At the same fibre content (1.0%), RTSF reinforced concrete exhibited a higher workability and air content than ISF reinforced concrete due to the different fibre shape and aspect ratio. The compressive strength of concrete at various strain rates went up with the increase of RTSF content from 0 to 0.75% but reduced with the further increase of RTSF content from 0.75% to 1.25%. DIFs of all mixtures were closely related to strain rate. The optimal dosage of RTSF for concrete was found to be 0.75%, considering workability, compressive strength, and dynamic compressive performance.

Enhancement of devolatilization performance in a rotating packed bed with different packing structures

• The 3D-printed mesh packing with drop-shaped fibers (PMP-D) was manufactured. • The PMP-D was employed to enhance the devolatilization performance in RPB. • Compared with traditional SMP, the η and K L a of PMP-D was drastically improved. • Correlations to predict K L a were established with deviations less than ±20%. The devolatilization of volatile organic compounds (VOCs) from the viscous liquid like polymers was necessary but of great challenge caused by the high viscosity. In this work, different packing structures were manufactured in a rotating packed bed (RPB), including the stainless steel wire mesh packing (SMP), 3D-printed column packing (PCP), 3D-printed mesh packing with circular fibers (PMP-C), and 3D-printed mesh packing with drop-shaped fibers (PMP-D). The devolatilization performance of the RPB was investigated with the acetone-silicon oil working system. Results indicated that modifying the fiber shape of packing effectively intensified the devolatilization in the RPB. The removal efficiency ( η ) and volumetric mass transfer coefficient ( K L a ) of the PMP-D were dramatically larger than the other three packings. Compared the PMP-D with the traditional SMP, the maximum η was enhanced from 40% to 50%, and the increment of K L a was 50% on average. The correlations to predict K L a were established, and the deviations from the experimental results were less than ± 20%.

Fabrication of Silica Optical Fibers: Optimal Control Problem Solution

In this work, a new approach to solving problems of optimal control of manufacture procedures for the production of silica optical fiber are proposed. The procedure of silica tubes alloying by the Modified Chemical Vapor Deposition (MCVD) method and optical fiber drawing from a preform are considered. The problems of optimal control are presented as problems of controlling distributed systems with objective functionals and controls of different types. Two problems are formulated and solved. The first of them is the problem of the temperature field optimizing in the silica tubes alloying process in controlling the consumption of the oxygen–hydrogen gas mixture (in the one- and two-dimensional statements), the second problem is the geometric optimization of fiber shape in controlling the drawing velocity of the finished fiber. In both problems, while using an analog to the method of Lagrange, the optimality systems in the form of differential problems in partial derivatives are obtained, as well as formulas for finding the optimal control functions in an explicit form. To acquire optimality systems, the qualities of lower semicontinuity, convexity, and objective functional coercivity are applied. The numerical realization of the obtained systems is conducted by using Comsol Multiphysics.

Round-Robin Tests with Relocatable Coverslips Improve Asbestos Fibre Counting.

Asbestos fibre counting by phase-contrast microscope is subject to many sources of variation, including those dependent on the analyst. In this study, asbestos sample slides prepared with relocatable coverslips have been used for fibre counting among voluntary analysts to evaluate their proficiency. One slide of amosite and one of chrysotile were distributed to all the analysts, and three proficiency testing rounds were conducted for amosite and four for chrysotile. Each relocatable coverslip has a report in which are reported for each viewing field both the number of certified fibres (Verified Fibres) and a drawing representing the shape and position of the individual fibres. In the first round, the analysts were asked to report only the number of fibres counted in each of the predesignated fields of view. In the other rounds, subsequently developed, the analysts had to report the number and the position of the fibres for each field. The reported number of fibres and their position in each of the designed fields were evaluated against their respective verified fibres, to identify types of error. Discrepancies between reported fibres and verified fibres in each field of view have been used to evaluate the proficiency of the analysts. The discrepancies can be positive (D+) or negative (D-) depending on whether the analyst counts, for a specific field of view, more or less fibres compared to the verified fibres. The score is calculated using the following equation: Score = (1 - ∑D+ + ∑│D-│/VF) × 100. An analyst obtaining a score of ≥60, which corresponds to (∑D+ + ∑│D-│)/VF ≤ 0.40, is proficient. The number of laboratories that participating in this study varied from 13 to 17 depending on the rounds. For amosite fibre counts, the results were generally good compared to a proficiency score of 60. The major error made by analysts was the counting of fibres shorter than 5 µm, where this error was of 62% of extra fibres and accounted for 8% over-estimation of amosite fibres. For chrysotile, a score of ≥50 has been used to consider an analyst as proficient. The results of chrysotile fibres showed that in the first round all analysts counted less than fifty per cent of the verified fibres. In the second round 10 analysts out of 13 reached a score of ≥50, 8 of 16 in the third and 10 of 12 in the fourth. For chrysotile fibres, the error relating to the counting of fibres shorter than 5 µm was of 56% of extra fibres, but the error that most influenced the results was the number of oversight-missing fibres. This type of error accounted for 97% of the missing fibres and for the 29% under-estimation of the chrysotile fibres. For amosite fibre counting, results of this study show an improvement of the analyst's performance. For the chrysotile fibre count, although there is a significant improvement in the comparison between some rounds, this is not continuous over time.

Flexible sensors based on assembled carbon nanotubes

AbstractFlexible sensors have attracted significant attention as they could be directly attached to/implanted into the body or incorporated into textiles to monitor human activities and give feedbacks for healthcare. A typical fabrication method is the direct use of intrinsically flexible active materials such as carbon nanotubes (CNTs). CNTs are generally assembled into aligned structures to extend their remarkable chemical, mechanical, and electrical properties to macroscopic scale to afford high sensing performances. In this review, we present the recent advance of CNT assemblies as electrodes or functional materials for flexible sensors. The realizations of aligned CNTs are firstly investigated. A variety of flexible sensors based on the aligned CNTs are then carefully explored, with an emphasis on understanding the working mechanism for their high sensing properties. The main attention is later paid to comparing two main categories of flexible sensors with fiber and film shapes. The remaining challenges are finally highlighted to offer some insights for future study.

Investigation of flow dynamics of thin viscous films down differently shaped fibers

The flow dynamics of a thin viscous film down on a fiber is associated with a variety of industrial applications. In this paper, we experimentally investigate the flow behaviors of a thin film falling on differently shaped fibers. For a spiral fiber, flow behaviors show three typical flow regimes as the cylindrical fiber, which indicates the isolated regime, Rayleigh–Plateau regime, and convective regime. However, the transition process of various fiber shapes is distinctively different. Unlike the cylindrical fiber, flow on a spiral fiber exhibits a wider range of flow rate in the Rayleigh–Plateau regime, which is helpful for the precise control of flow patterns in a relatively stable regime. We further quantitatively investigate three important characteristic parameters of flow dynamics of a spiral fiber, i.e., bead velocity, thickness, and spacing. Results reveal that a thin film on a spiral fiber has a higher bead velocity, larger bead thickness, and larger bead spacing. Our findings provide important insights for understanding flow dynamics of a thin viscous film down on shaped fibers, which may also inspire coating flow control methods in various applications.

The effects of fiber radius and fiber shape deviations and of matrix void content on the strengths and failure mechanisms of UD composites by computational micromechanics

Manufacturing plays an important role in the properties of composites, which may lead to two types of uncertainties: (1) carbon fiber manufacturing deviations, such as the bean-shaped PAN carbon fibers, the lognormal-distributed fiber radius, etc. (2) composites manufacturing deviations, such as the inter-fiber voids and matrix voids. Although several experiments have been conducted to assess their effects on the mechanical properties of composites, a satisfactory result of quantitative characterization of fiber radius and fiber shape deviations and of matrix void content have not been obtained. In this paper, a parametric study based on the computational micromechanics is conducted to reveal the effects of fiber radius and fiber shape deviations and of matrix void content on the strengths and failure mechanisms of UD composites under four loading conditions, i.e. the transverse tension, compression, shear and longitudinal shear. Firstly, the constitutive laws of constituents, i.e. carbon fiber, matrix and interface, are established to characterize their mechanical responses. Then, the UD RVEs with fiber radius and fiber shape deviations and with matrix void are modeled individually based on experimental observation and statistical distribution. After qualitative validation of failure modes and quantitative validation of stress-strain curves, the methodology is applied to predict the stress-strain curves and failure modes of UD RVE with manufacturing uncertainties and the results show that not all manufacturing uncertainties have a detrimental effect on the mechanical properties of UD composites.

Ultrasensitive Strain Sensor Based on Mach-Zehnder Interferometer With Bent Structures

In this paper, an all-single-mode fiber strain sensor based on a bent structure Mach-Zehnder interferometer (BS-MZI) is proposed. This sensor consists of two identical bent structures, one of which excites the cladding modes, and the other couples them back to the core. Interference occurs when the cladding and the core modes meet each other. Therefore, the bent structures function as an MZI. The bent structures are fabricated by releasing the pulse of the CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser along the specific designed paths. The fiber shaping method based on CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser polishing is flexible, which is demonstrated in detail. The unique geometrical shape of the bent structures brings high strain sensitivity to the sensor. As a consequence, the sensor with a length of 9.6 mm exhibits an ultrahigh strain sensitivity, which reaches 165 pm/μϵ. Experimental results show that the strain responses of the BS-MZIs are highly correlated with their interference lengths and the modulated lengths. Its temperature-strain cross-sensitivity is as low as 0.21 μϵ/°C. Moreover, the sensor exhibits high stability and repeatability in strain measurement, which makes it a promising sensor in strain measurement.

Unravelling capability of municipal wastewater treatment plant in Thailand for microplastics: Effects of seasonality on detection, fate and transport

Many factors can affect microplastics (MPs) behaviors in aquatic environments. The effects of seasonal and meteorological conditions on MPs are not well understood. This study demonstrates the impacts of seasonality on the fate and transport, and the efficacy of MPs removal by a wastewater treatment plant. The fate and transport of MPs at a WWTP in Nonthaburi, Thailand were tracked during the dry and wet seasons of 2019–2020. Polypropylene (PP), polyethylene (PE), and toothpaste formulations were the most abundant MP types observed. Total detected MP quantities ranged between 76 and 192 particles L−1 during the dry season, and only 36–68 particles L−1 during the wet season, indicating runoff dilution effects. T-test analysis found a statistically significant difference between MP concentrations between the dry and wet seasons of 2019–2020. Spearman's correlation showed statistically strong negative relationships between MP concentrations versus wastewater flow, and MP concentrations versus precipitation; a positive correlation between MP abundance versus temperature in the treatment system was observed. During the dry seasons, MPs were mostly found in the aeration process, and were mostly rayon or polyester particles in the shape of fibers. Contrarily, in the wet seasons, MPs were detected in both the raw influent and aeration process, with PE, polyacrylate, and polyethylene terephthalate fragments dominating the make-up. MPs were also detected in the return activated sludge, thus calling for proper sludge age and drainage management. No MPs were detected in the plant's effluent during the wet season, suggesting that the plant had sufficient MPs removal capability during normal wet-season conditions. Overall, this study suggests that municipalities should focus on increasing MPs removal efficiency of wastewater treatment plants for dry seasons, while properly managing the water flows of combined sewage systems to prevent overflows that may inevitably become point-sources of MPs release into water bodies during wet seasons.

A numerical homogenization technique for unidirectional composites using polygonal generalized finite elements

The present study proposes a computational methodology to obtain the homogenized effective elastic properties of unidirectional fibrous composite materials by using the generalized finite-element method and penalization techniques to impose periodic boundary conditions on non-uniform polygonal unit cells. Each unit cell is described by a single polygonal finite element using Wachspress functions as base shape functions and different families of enrichment functions to account for the internal fiber influence on stresses and strains fields. The periodic boundary conditions are imposed using reflection laws between two parallel opposing faces using a Lagrange multiplier approach; this reflection law creates a distributed reaction force over the edges of the [Formula: see text]-gon from the direct application of a given deformation gradient, which simulates different macroscopic load cases on the macroscopic body the unit cell is part of. The methodology is validated through a comparison with results for similar unit cells found in the literature and its computational efficiency is compared to simple cases solved using a classic finite-element approach. This methodology showed computational advantages over the classic finite elements in both computational efficiency and total number of degrees of freedom for convergence and flexibility on the shape of the unit cell used. Finally, the methodology provides an efficient way to introduce non-circular fiber shapes and voids.

Shape Sensing Using Two Outer Cores of Multicore Fiber and Optical Frequency Domain Reflectometer

A method, i.e., vector projections, using two outer cores of multicore fiber without calibration and OFDR was proposed to realize three-dimensional (3D) shape sensing. A complement for apparent curvature vector method using three outer cores of multicore fiber was also proposed to determine the viable fiber cores arrangement for shape sensing. Compared with apparent curvature vector method, the vector projections method based on two outer cores of multicore fiber decreased the number of fiber cores, which eliminating the requirement for fiber cores arrangement. Based on these methods, a reconstructed shape with a higher accuracy was obtained based on integrating all fiber shape from all cores combinations. The maximum root-mean-square errors (RMSEs) of end position for the vector projections and apparent curvature vector method were 13.1 and 12.4 mm, while a higher accuracy, i.e., maximum RMSEs of 11.9 and 12.1 mm, was obtained based on the integrated fiber shapes.

Enhanced Modeling of Water Diffusion in Natural Fibers: Application to Diss Fibers

ABSTRACT Water diffusion through natural fibers represents an important aspect with regard to the integrity of biocomposites. Usually, diffusion model is defined assuming circular fiber cross-sections, while microscopic analysis findings revealed other geometries. This was found to affect the modeling of water transport through fibers and provide a gap versus experimental data. This work aims to present a numerical approach using finite element method to overcome the limits of use of analytical approaches relating to the morphological shape of vegetal fibers. The cross-section of the Diss fibers was observed by an optical microscope and simulated at an ellipsoidal shape after processing the images. Then, the average morphological parameters were determined. A numerical finite element model was implemented based on the observed geometry in order to determine the diffusion coefficient by an inverse approach compared to experimental results. The results showed that the numerical approach made it possible to raise the effect of fiber morphology, often assumed to be circular for plant fibers in analytical approaches, on the diffusion coefficient value, which was defined by a unique diffusion coefficient.

Synthesis of Hard Carbon from Waste Teak Wood Powder as Anode Material for Lithium-ion Batteries

Electrochemical energy storage technologies such as rechargeable batteries show considerable progress due to their high efficiency, flexible power, long life cycle, and low maintenance. Graphite is a common anode material used in lithium-ion batteries. However, there are several shortcomings in graphite anode material, one of which is poor structural stability. Therefore, hard carbon is the most promising candidate for lithium-ion battery anodes due to its high storage capacity, low working potential, and cycle stability. This research utilizes teak sawdust waste as a hard carbon battery anode. They were approached by the carbonization method at temperatures of 350°C and 450°C. In general, X-Ray Diffraction (XRD) results show an amorphous structure of carbon atoms. The morphological structure known through the Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) test shows a fiber shape. The mass percent of carbon at a temperature of 450°C was higher than at a temperature of 350°C, which was 67.93%. Then the battery performance test was carried out with the highest discharge capacity value obtained at a temperature of 450°C at 191.56 mAh/g. Based on the results of this study, teak sawdust waste material has the potential as an anode for rechargeable batteries and can prevent environmental pollution.

Micromechanical models for predicting the mechanical properties of 3D-printed wood/PLA composite materials: A comparison with experimental data

Analytic modeling of 3 D printed natural fiber-reinforced composites is still in its infancy. The existing analytic works on the mechanical properties of these materials seem to be relatively few in spite of their practical interest. However, the mechanical properties are one of the most important parameters that define the structural behavior of the material. A micromechanical approach is used in the present study, to predict the elastic properties of 3 D printed wood/PLA composites (WPC). The results of the micromechanical models were validated using the experimental data. The comparison revealed a good correlation with the Mori-Tanaka model, which the maximum deviations were lower than 20%. Moreover, a parametric study showed that the elastic properties of the composites depended strongly on the fiber content, the fiber shape, and the porosity rate.

Effect of Fiber Shape on the Tribological, Mechanical, and Morphological Behaviors of Sisal Fiber-Reinforced Resin-Based Friction Materials: Helical, Undulated, and Straight Shapes.

In this paper, we aim to evaluate the tribological, mechanical, and morphological performance of resin-based friction composites reinforced by sisal fibers with different shapes, namely helical, undulated, and straight shapes. The experimental results show that the shape of the sisal fibers exerts a significant effect on the impact property of the composite materials but no obvious influence on the density and hardness. The friction composite containing the helical-shaped sisal fibers exhibits the best overall tribological behaviors, with a relatively low fade (9.26%), high recovery (98.65%), and good wear resistance (2.061 × 10−7 cm3∙N−1∙m−1) compared with the other two composites containing undulated-shaped fibers and straight-shaped fibers. The impact fracture surfaces and worn surfaces of the composite materials were inspected by scanning electron microscopy, and we demonstrate that adding helical-shaped sisal fibers into the polymer composites provides an enhanced fiber–matrix interface adhesion condition and reduces the extent of fiber debonding and pullout, effectively facilitating the presence of more secondary plateaus on the friction surface, which are responsible for the enhanced tribological and mechanical properties. The outcome of this study reveals that sisal fibers with a helical shape could be a promising candidate as a reinforcement material for resin-based brake friction composite applications.