Fiber Position Research Articles

A Comprehensive Study on Measurement Accuracy of Distributed Fiber Optic Sensors Embedded within Capillaries of Solid Structures.

Embedding fiber optic sensors (FOSs) within parts for strain measurement is attracting widespread interest due to its great potential in the field of structural health monitoring (SHM). This work proposes a novel method of embedding FOSs using capillaries within solid structures and investigates fiber positions and orientation uncertainties within capillaries of different sizes and their influences on strain measurement accuracies. To investigate how the fiber positions and orientation variations influence strain measurement accuracy, both analytical and numerical models are utilized to predict strain distributions along embedded fibers at different positions and with different orientations within the specimen. To verify the predictions, a group of specimens made of Aluminum 6082 was prepared, and the specimens in each group had capillaries of 2 mm, 4 mm, and 6 mm diameters, respectively. Fibers were embedded within each specimen using the capillaries. Four-point bending static tests were conducted for each specimen with embedded FOSs, performing in situ strain measurement. Subsequently, the specimens were partitioned into several pieces, and the cross sections were observed to know the real positions of the embedded fiber. Finally, the strain predictions at the real locations of the fiber were compared with the measured strain from the embedded FOSs. The predicted strain distributions as a function of the fiber positions alone and as a function of both the fiber positions and orientations were compared to assess the influence of fiber orientation change. The results from a combination of analytical, numerical, and experimental techniques suggest that the fiber position from the capillary center is the main factor that can influence strain measurement accuracies of embedded FOSs, and potential fiber misalignments within the capillary had a negligible influence. The fiber position-induced measured error increases from 10.5% to 18.5% as the capillary diameter increases from 2 mm to 6 mm. A 2 mm capillary diameter is able to lead to the lowest measurement error in this study and maintains ease of embedding. In addition, it is found that the measured strain always lies within a strain window defined by the strain distribution along capillary boundaries when there are no cracks. This can be further studied for crack detection.

Two-dimensional patterning of mesoscale fibers using acoustophoresis

The performance of functional composites can rely critically on the arrangement of secondary phases; for example, patterned networks of conductive particles can impart anisotropic thermal, electric or ionic conductivity while preserving flexibility in the matrix. We demonstrate the use of standing acoustic waves to generate periodic patterns of short fibers. We extend the range of possible patterns with the first demonstration of both rectangular grids and arrays of octagons interspersed with rectangles. These newly demonstrated patterns are rationalized using theoretical models of acoustic forces and torques on fibers that account for two-dimensional spatial variations arising from applied acoustic fields. The models enable simulations of fiber motion, which are used to (i) map out final fiber positions as a function of initial position and orientation, and (ii) corroborate experiments visualizing fiber motion and final patterns. This approach provides a fast and accurate way to predict emergent fiber patterns as a function of excitation modality and fiber length. The theory and experiments clearly indicate strong coupling between the length of the fibers and the spacing of the acoustic nodes. This coupling is used to estimate reductions in percolation thresholds associated with the ratio of fiber length and acoustic wavelength.

Molecular Characterisation of Partial Structural Genes of Fowl Adenovirus Serotype 8b UPMT1901 Field Strain Isolate Associated with the Inclusion Body Hepatitis in Malaysia’s Commercial Broiler Chickens

Fowl adenovirus (FAdV) is reported to pose a severe risk to the poultry industry, affecting food and nutrient security nationally and globally. FAdV is identified as the primary pathogen for inclusion body hepatitis (IBH) disease in avians during outbreaks in farms. Numerous interventions have been employed to reduce the chicken’s mortality rate in future outbreaks, such as local autogenous vaccine production that has yet to be successfully commercialised. Fibre and hexon protein are two out of the three major components of the adenoviral capsid, identified to contribute towards FAdV virulence. Hence, this study aims to determine the fibre and hexon gene molecular changes of a local isolate, FAdV UPMT1901, in Malaysia’s recent IBH outbreak and identify the evolutionary relationship with known FAdV strains. Propagation of FAdV UPMT1901 was performed in specific pathogen-free embryonated chicken prior to genomic extraction. The genes were amplified, and the retrieved nucleotide sequences were aligned with the published FAdV sequences. The phylogenetic tree analysis showed that UPMT1901 partial fibre and hexon genes are 99% similar to other known FAdV serotype 8b (FAdV-8b) species, especially the published Malaysian FAdV-8b isolates. Interestingly, the amino acid residue analysis further supported consistent residues amongst Malaysian isolates at fibre positions T176A, Q195H, D213E, S243T, A258V, F335Y, and F353V and hexon position T422M. These findings elucidate the structural proteins’ functional capacity and molecular diversity, specifically amongst Malaysian FAdV isolates and FAdV-8b, while contributing to global initiatives to establish biosecurity, such as a vaccine or antiviral production against future outbreaks.

Detecting gas pipeline leaks in sandy soil with fiber-optic distributed acoustic sensing

Detecting pinhole leaks in long-haul buried gas pipelines is challenging due to weak leak signals and large spans. Fiber-optic distributed acoustic sensing (DAS) technology offers highly sensitive long-distance monitoring. This study evaluates DAS for detecting pinhole gas leaks in pipelines buried in sandy soil. Controlled experiments examined the effects of pipe-to-fiber distance, fiber position, leak direction, gas pressure, and leak diameter. Pressurized gas erodes the overlying soil, forming cavities and fissures that change soil morphology. Gas preferentially diffuses upward; an optical fiber above the pipe has the highest sensitivity regardless of leak direction and should be deployed above pipelines. Two mechanisms produce DAS-recorded leak vibration signals: dynamic soil straining and gas–fiber friction. Vibration energy from dynamic soil motion concentrates at 60–120 Hz while gas–fiber friction exhibits a broader spectral response. Increasing gas pressure or leak diameter increases detected vibration power but decreases peak frequency and proportion generated by soil strain, indicating a shift toward gas–fiber friction as the dominant mechanism. These results inform improved pinhole leak monitoring in buried gas pipelines using DAS technology.

Trajectory monitoring method based on optical sensing spectral energy and adaptive threshold

Distributed optical fiber sensing technology is widely used in structural health monitoring, security systems and other fields. The traditional monitoring method of electrical measurement can ensure monitoring accuracy of train trajectory, while this method is easily affected by thunderstorm weather. In order to simultaneously improve the anti-interference ability and monitoring accuracy, this paper proposes a trajectory monitoring method based on optical sensing spectral energy and adaptive threshold. This method only needs to monitor the backward Rayleigh scattering optical signal of a redundant communication fiber, and perform Fourier transform and spectral energy operation to analyze vibration signals of the entire line. An adaptive threshold algorithm is utilized to autonomously locate fiber position of the train and form a spatial–temporal trajectory map. The method proposed in this paper is a passive monitoring method using optical sensing, which greatly improves system’s ability to resist electromagnetic interference, reduces the monitoring cost of the entire system, and effectively ensures the positioning accuracy. Experimental results demonstrate the effectiveness, safety, and accuracy of the train trajectory monitoring method based on optical sensing spectral energy and adaptive threshold.

Multi-nodes dissemination of stable radio frequency with 10-17 instability over 2000 km optical fiber.

To meet the demand of flexible access for high-precision synchronization frequency, we demonstrate multi-node stable radio frequency (RF) dissemination over a long-distance optical fiber. Stable radio frequency signals can be extracted at any node along the optical fiber, not just at the endpoint. The differential mixing structure (DMS) is employed to avoid the frequency harmonic leakage and enhance the precision. The phase-locked loop (PLL) provides frequency reference for the DMS while improving the signal to noise ratio (SNR) of dissemination signal. We measure the frequency instability of multi-node stable frequency dissemination system (MFDS) at different locations along the 2,000 km optical fiber. The measured short-term instability with average time of 1 s are 1.90 × 10-14 @ 500 km, 2.81 × 10-14 @ 1,000 km, 3.46 × 10-14 @ 1,500 km, and 3.84 × 10-14 @ 2,000 km respectively. The long-term instability with average time of 10,000 s are basically the same at any position of the optical fiber, which is about (6.24 ± 0.05) × 10-17. The resulting instability is sufficient for the propagation of precision active hydrogen masers.

Pengaruh pH Asam Terhadap Kekuatan Mekanik Fiber E-Glass: Systematic Review

Background: Dental fibers were first introduced by Smith (1960) which are used in various fields of dentistry. Dental fibers are classified into two categories, natural and synthetic. Glass fiber that is often used in dentistry is E-glass fiber because of its resistance to chemical reactions, has good aesthetic properties, has almost the same mechanical properties as dentin and is biocompatible. In the oral cavity, acidic conditions occur due to consumption of food and beverages containing acid. Acidic conditions in the oral cavity can affect the mechanical properties of the composite resin. Factors that affect the mechanical properties of fiber reinforced composite are the properties of the composite material and fiber used, fiber quantity, fiber position, fiber direction, fiber adhesion to the composite matrix. To determine and study the effect of acidic pH on the mechanical strength of e-glass fibers. Method: This type of research is a literature review using a systematic review approach.Result: The decrease in compressive strength and resistance was influenced by structural disturbances and loss of most components due to acid exposure. The decrease in the tensile strength of the glass fiber increases the time associated with immersion of the fiber surface which can interfere with the continuity of the e-glass network. Acidic drinks, carbonated drinks, and alcohol can produce erosion on the surface of the composite resin. The longer the immersion, the more solution particles that enter the resin microporosity space and reduce the strength of the composite resin.Conclusion: The mechanical strength of e-glass fiber will decrease with the length of exposure to acid. Types of acids that can affect the decline in mechanical strength are strong acids such as hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), and phosphoric acid (H3PO4).

Ecosystem sustainability and conservation of waste natural fiber strengthen epoxy composites for lightweight applications

AbstractIn recent days, the automobile, aerospace, and marine sectors are imposed to search the similar quality alternative material with desired mechanical and wear characteristics obtained by using natural fiber extracted from environmental wastes. The current investigational characteristics study focuses to increase the mechanical properties of composite by using NaOH‐treated natural fiber like jute and sisal bonded with epoxy resin via the wet filament technique. The four different positions of fibers like the jute‐sisal fiber were dipped with epoxy resin and waved as random (multi‐directional), 0° (unidirectional), 90° (bi‐directional), and interlock position. The developed natural fiber composites were subjected to tensile, impact, and flexural strength made by ASTM procedure. The composite prepared with interlock position showed higher tensile, impact, and flexural strength 49.51 ± 1.51 MPa, 12 ± 0.98 J, and 57.31 ± 1.98 MPa respectively and improved by 12%, 33.3%, and 10% as compared to random (multi‐directional) composite. So the developed composites were enhanced by the conservation of jute/sisal fiber bonded with epoxy as interlocking distribution is utilized for lightweight applications and the conservation of waste natural fiber retained the ecosystem sustainability.

Mechanisms for Introduction of Pseudo Ductility in Fiber Reinforced Polymer Composites- A Review

Advanced polymer matrix composites are gaining the market in their way due to their exceptional specific stiffness, specific strength, fatigue, and corrosion resistance in the field of Auto-Tech, Aero-Tech, Biotech, etc. However, the lack of ductility and catastrophic failure has limited their application in these areas. Hence there is a need to explore means and protocols for designing the reduced factor of safety with high-performance toughened composites. To address this problem, a new generation of high-performance composites with pseudo-ductile or ductile behavior is needed. The ongoing High-Performance Ductile Composite Technology (HiPerDuCT) program jointly between the University of Bristol U.K and Imperial College London to address this challenge by developing newer materials. The fiber architectures made under this project gave a more gradual failure rather than catastrophic failure which improves the mechanical properties. This paper mainly focuses on addressing this evolution of pseudo ductility in fiber-reinforced composites. In addition to this, an attempt has been made to newer possible fiber positions in matrix materials for inducing reasonable ductility in composites.

EXPLORING THE RELATIONSHIP BETWEEN YARN TYPE AND PACKING DENSITY: A STUDY OF SINGLE-PLY, TWO-PLY, AND SIRO-SPUN YARNS

Studying the fiber positioning in the yarn structure is the essential point to understand the different characteristics of yarns that counted as alternatives to each other. This study explores the packing densities of single-ply, two-ply and Siro-spun spun yarns that have been stated as the alternative yarn types considering the production method or yarn structure. In the study, Modal, Tencel, polyethylene teraphtalete, and cotton fibers represent micro, regenerated, synthetic, and natural fibers were used for the production of the 29.50 Tex yarns. Cross-sectional views of the yarns were acquired according to the hard sectioning method, and the packing densities of yarns were calculated with image processing tools. Yarn packing densities were calculated as the ratio of total fiber area within the yarn cross-section to yarn cross-section. Results showed that single ply ring-spun and siro-spun yarns are in a more circular shape and have greater packing densities values than two-ply yarns. Besides, yarns produced from cotton fibers have the least packing density values in each spinning technology. Similar packing density values were obtained for micro Modal, Tencel, and PET single-ply and siro-spun yarns. Packing density values were also compared with USTER diameter and density values and significant relations between those values were found.

Optical Frequency-Domain Reflectometry Based Distributed Temperature Sensing Using Rayleigh Backscattering Enhanced Fiber

An innovative optical frequency-domain reflectometry (OFDR)-based distributed temperature sensing method is proposed that utilizes a Rayleigh backscattering enhanced fiber (RBEF) as the sensing medium. The RBEF features randomly high backscattering points; the analysis of the fiber position shift of these points before and after the temperature change along the fiber is achieved using the sliding cross-correlation method. The fiber position and temperature variation can be accurately demodulated by calibrating the mathematical relationship between the high backscattering point position along the RBEF and the temperature variation. Experimental results reveal a linear relationship between temperature variation and the total position displacement of high backscattering points. The temperature sensing sensitivity coefficient is 7.814 μm/(m·°C), with an average relative error temperature measurement of −1.12% and positioning error as low as 0.02 m for the temperature-influenced fiber segment. In the proposed demodulation method, the spatial resolution of temperature sensing is determined by the distribution of high backscattering points. The temperature sensing resolution depends on the spatial resolution of the OFDR system and the length of the temperature-influenced fiber. With an OFDR system spatial resolution of 12.5 μm, the temperature sensing resolution reaches 0.418 °C per meter of RBEF under test.

Prognostic value of tumor necrosis based on the evaluation of frequency in invasive breast cancer

BackgroundTumor necrosis (TN) was associated with poor prognosis. However, the traditional classification of TN ignored spatial intratumor heterogeneity, which may be associated with important prognosis. The purpose of this study was to propose a new method to reveal the hidden prognostic value of spatial heterogeneity of TN in invasive breast cancer (IBC).MethodsMultiphoton microscopy (MPM) was used to obtain multiphoton images from 471 patients. According to the relative spatial positions of TN, tumor cells, collagen fibers and myoepithelium, four spatial heterogeneities of TN (TN1-4) were defined. Based on the frequency of individual TN, TN-score was obtained to investigate the prognostic value of TN.ResultsPatients with high-risk TN had worse 5-year disease-free survival (DFS) than patients with no necrosis (32.5% vs. 64.7%; P < 0.0001 in training set; 45.8% vs. 70.8%; P = 0.017 in validation set), while patients with low-risk TN had a 5-year DFS comparable to patients with no necrosis (60.0% vs. 64.7%; P = 0.497 in training set; 59.8% vs. 70.8%; P = 0.121 in validation set). Furthermore, high-risk TN “up-staged” the patients with IBC. Patients with high-risk TN and stage I tumors had a 5-year DFS comparable to patients with stage II tumors (55.6% vs. 62.0%; P = 0.565 in training set; 62.5% vs. 66.3%; P = 0.856 in validation set), as well as patients with high-risk TN and stage II tumors had a 5-year DFS comparable to patients with stage III tumors (33.3% vs. 24.6%; P = 0.271 in training set; 44.4% vs. 39.3%; P = 0.519 in validation set).ConclusionsTN-score was an independent prognostic factor for 5-year DFS. Only high-risk TN was associated with poor prognosis. High-risk TN “up-staged” the patients with IBC. Incorporating TN-score into staging category could improve its performance to stratify patients.

Method and Application of Spatial Positioning for Valid Temperature-measuring Optical Fibers in Concrete Dams

Spatial positioning of Valid Temperature-measuring Optical Fiber (VTOF) is of great significance for accurately grasping the real temperature distribution of a concrete dam. However, there is barely an effective way to accurately locate the measuring points of optical fiber in concrete dams. A comprehensive data symmetry analysis technique is presented for determining the optimal spatial positioning of valid temperature-measuring optical fibers (VTOFs) in concrete dams. This approach includes a mathematical model to confirm the center of symmetry in monitoring data, which is required to reconstruct the real spatial temperature distribution. This process can identify VTOF locations and verify the reliability of temperature predictions. Experimental validation was conducted using findings from research on a new mathematical model, site measurements from a concrete dam, and corresponding data from distributed optical fibers. These results were successfully applied to the construction of the Baihetan dam; the concrete temperature from 405 pouring blocks in 5 typical dam monoliths was accurately monitored, and the temperature-measuring points of VTOFs were more than 24711. Meanwhile, the optical fiber temperature measurement and temperature field analysis system of Baihetan dam located in southwest China was developed based on accurately acquired temperature measurement data, which provides data basis and engineering application platform support for temperature evolution and temperature field analysis and precise temperature control management of pouring blocks.

Highly sensitive SPR curvature sensor based on graded-index fiber.

At present, fiber curvature sensors based on surface plasmon resonance (SPR) are mostly of the multimode fiber core type or cladding type. These types have many SPR modes, resulting that the sensitivity cannot be adjusted and is difficult to improve. In this Letter, a highly sensitive SPR curvature sensor based on graded-index fiber is proposed. The light-injecting fiber is eccentrically connected with the graded-index fiber to inject single-mode light. Due to the self-focusing effect, the light beam propagates in the graded-index multimode fiber with a cosine trajectory, and the cosine beam contacts the flat grooved sensing region fabricated on the graded-index fiber to generate SPR. Due to the single transmission mode of the proposed fiber SPR sensor, the curvature sensing sensitivity is greatly improved. By changing the light injection position of the graded-index multimode fiber, the sensitivity can be adjusted. The proposed curvature sensing probe has a high sensitivity and can identify the bending direction. When bending in the X direction, the sensitivity reaches 5.62 nm/m-1, and when bending in the - X direction, the sensitivity reaches 4.75 nm/m-1, which provides a new scheme for highly sensitive and directionally identifiable curvature measurement.

Coupling Efficiency of a Spot Size Converter for Optical Fiber-Chip Connections

The light propagation in optical waveguide must be able to maintain low propagation loss, low coupling loss and scattering loss condition, especially in the junction. In this research, a spot size converter is proposed to preserve the lowest coupling loss. This optical converter is composed of a single mode optical fiber (SiO2) including inversed taper. The optical input signal from the optical fiber is launched into photonic integrated circuits and then coupled into the Si-Slab waveguide. Furthermore, linear form with the length dependence has been studied to obtain the optimal position of optical fiber and the chip and analyzed the coupling efficiency of it. The purpose of this research is to procure the optimal form of spot size converter. The simulation result shows the coupling loss of linear form is 0.62 dB and 0.24 dB on TE and TM mode condition respectively. Along with the increase in the taper length, the coupling loss obtained tends to decrease as well. So that, it can be assumed the design of a linear form with 100 μm taper length provides the highest coupling efficie ncy.

Fluorescence-guided laser lithotripsy: Estimation of the potential effectiveness and safety increase based on first clinical data.

In clinically approved laser lithotripsy systems, there is no automatic monitoring of fiber position to date. We investigated whether detecting stone autofluorescence, excited by a green aiming beam, is possible via the fiber during fragmentation by continuously recording the fluorescence signal in 12 ureterosopic lithotripsy procedures. We estimated which threshold the fluorescence signal's amplitude exceeds before laser pulses with visible stone removal by retrospective inspection of the endoscope's video data. For all procedures, blocking the laser when the fluorescence amplitude is below a threshold corresponding to the signal's baseline plus its range (maximum-minimum value) would have been appropriate to suppress ineffective pulses-the energy input could have been reduced by a mean of 14% (1%-29%) without changing the operation time. Ablation of the PTFE coating of the guidewire could have been prevented three times and cutting of a wire of the retrieval basket two times.

Toward a better understanding of angiosperm xylogenesis: a new method for a cellular approach.

The kinetics of wood formation in angiosperms are largely unknown because their complex xylem anatomy precludes using the radial position of vessels and fibers to infer their time of differentiation. We analyzed xylogenesis in ring-porous ash (Fraxinus angustifolia) and diffuse-porous beech (Fagus sylvatica) over 1 yr and proposed a novel procedure to assess the period of vessel and fiber enlargement using a referential radial file (RRF). Our approach captured the dynamics of wood formation and provided a robust estimation of the kinetics of vessel and fiber enlargement. In beech, fibers and vessels had a similar duration of enlargement, decreasing from 14 to 5 d between April and July. In ash, wide vessels formed in April enlarged at a rate of 27 × 103 μm2 d-1 , requiring half the time of contemporary fibers (6 vs 12 d), and less time than the narrower vessels (14 d) formed in May. These findings reveal distinct cell-type-dependent mechanisms for differentiation in diffuse-porous and ring-porous trees, enhancing our understanding of angiosperm wood cell kinetics. Our approach presents an effective method for investigating angiosperm wood formation and provides a more accurate representation of vessel and fiber morphogenesis in wood formation models.

Accuracy of robot-assisted stereotactic MRI-guided laser ablation in children with epilepsy.

Robot-assisted (RA) stereotactic MRI-guided laser ablation has been reported to be a safe and effective technique for the treatment of epileptogenic foci in children and adults. In this study the authors aimed to assess the accuracy of RA stereotactic MRI-guided laser fiber placement in children and to identify factors that might increase the risk of misplacement. A retrospective single-institution review of all children from 2019 to 2022 who underwent RA stereotactic MRI-guided laser ablation for epilepsy was undertaken. Placement error was calculated at the target by measuring the Euclidean distance between the implanted laser fiber position and the preoperatively planned position. Collected data included age at surgery, sex, pathology, date of robot calibration, number of catheters, entry position, entry angle, extracranial soft-tissue thickness, bone thickness, and intracranial catheter length. A systematic review of the literature was also performed using Ovid Medline, Ovid Embase, and the Cochrane Central Register of Controlled Trials. In 28 children with epilepsy, the authors assessed 35 RA stereotactic MRI-guided laser ablation fiber placements. Twenty (71.4%) children had undergone ablation for hypothalamic hamartoma, 7 children (25.0%) for presumed insular focal cortical dysplasia, and 1 patient (3.6%) for periventricular nodular heterotopia. Nineteen children were male (67.9.%) and 9 were female (32.1%). The median age at the time of the procedure was 7.67 years (IQR 4.58-12.26 years). The median target point localization error (TPLE) was 1.27 mm (IQR 0.76-1.71 mm). The median offset error between the planned and actual trajectories was 1.04° (IQR 0.73°-1.46°). Patient age, sex, pathology and the time interval between date of surgery and robot calibration, entry position, entry angle, soft-tissue thickness, bone thickness, and intracranial length were not associated with the placement accuracy of the implanted laser fibers. However, the number of catheters placed did correlate with the offset angle error on univariate analysis (ρ = 0.387, p = 0.022). There were no immediate surgical complications. Meta-analysis indicated that the overall pooled mean TPLE was 1.46 mm (95% CI -0.58 to 3.49 mm). RA stereotactic MRI-guided laser ablation for epilepsy in children is highly accurate. These data will aid surgical planning.

Minimum potential method appropriate to generate 2D RVEs of composites with high fiber volume fraction

This work proposes a novel method, entitled minimum potential method, to generate Representative Volume Elements (RVEs) of unidirectional fibers composites with high fiber volume fractions (FVFs, generally ≥70.0%). In the proposed method, a given VF of random and periodic fibers are initially created within the matrix and the fiber overlap is allowed, and then the fiber overlap is gradually removed by adjusting the fiber centroids based on the principle of the minimum overall potential. In the process of fiber overlap removal, the fiber periodicity and the fibers completely or partly contained in the matrix are preserved. The overall potential of the fibers consists of fiber overlap potential, fiber position potential and fiber periodicity potential, and is minimized using the gradient descent method. The numerical implementation of the proposed method is detailed, and the RVEs of the composites with various FVFs are generated. Through the probability distribution function of the nearest neighbor distance, the cumulative probability distribution function of the nearest neighbor orientation angle, the second-order intensity and pair correlation functions, the fiber distribution in the generated RVEs is analyzed, and the results indicate a completely random distribution of the fibers in the generated RVEs. Comparing with the available experimental test, the literature and the Double-Inclusion model, the proposed method to generate RVEs of the composites with high FVFs is validated.

The model of ring-spun slub yarn based on random fiber arrangement and its application: Part 1. Study on the relationship between fiber distribution and the length of the transitional segment of slub yarn

In this paper, the research on the transitional segment of slub yarn mainly focuses on the length of the transitional segment. Slub yarn was simulated by randomly determining the fiber position with the Monte Carlo method according to the draft principle of ring spinning for slub yarn. The length of the transitional segment was obtained by determining its starting and ending position according to the mass curves of the simulated and real-spun slub yarns. According to the data analysis, the fiber length, acceleration and deceleration time on draft rollers’ velocity, and slub multiple affect the length of the transitional segment. Both the lengths of the left and right transitional segments are all equal. The maximum error rate of the simulated value to the measured value of the length of the transitional segment is approximately 12%. The empirical formula has been established to estimate the length of the transitional segment. Compared with those of the simulated and real spun slub yarns, the error rate of the length of the transitional segment calculated by the empirical formula is less than 10%. The research content of this paper provides a basis for studying the appearance and properties of slub yarn.