The contact state between yarn and the disc in the disc friction false-twisting machine affects the yarn quality. Previous studies have the contact state between yarn and disc has been discussed. However, the specific imaging methods were not suggested. In this study, we developed an imaging system that uses a collaborative robot to accurately and instantly observe the contact state. Using this system, the apparent yarn thickness, twist angle, and inclination angle on all discs within the unit were measured precisely from three directions. As a result, the apparent yarn thickness was found to be influenced by the draw ratio. Additionally, as the yarn passed through discs, twist angle increased and inclination angle of yarn decreased, confirming their interrelationship. Furthermore, it was observed that twist angle decreased downstream of the disc unit, suggesting that the contact state between yarn and the disc becomes unstable in this region. It was revealed that this system could be utilized for evaluating various disc units in future studies.

This study proposes a method to enhance the recyclability of glass fiber-reinforced plastics (GFRP) by imparting dismantling ability to thermosetting adhesives through microwave irradiation. Single-walled carbon nanotubes (SWCNT) were added to epoxy adhesives at concentrations ranging from 0.2 to 1.0 wt%. The results showed that adhesive strength improved at 0.2–0.6 wt% for epoxy. Additionally, thermal decomposition and successful disassembly were observed at concentrations of ≧ 0.6 wt% for epoxy under microwave irradiation. This approach provides a promising bonding technology that enables both strong adhesion and easy disassembly, contributing to improved recyclability of FRP structures.

This study provides a comprehensive analysis of the dobby heald lifting mechanism's role in the textile weaving process. It specifically focuses on motion control methods aimed at improving yarn tension and fabric quality. The study proposes an optimized heald frame motion law to address the negative impact of heald movement on warp tension and yarn breakage rate. By utilizing a reverse modeling approach, the study uncovers the intricate relationship between the lifting mechanism's components and their contribution to achieving precise lifting. This approach involves finding cam profile solutions based on theoretical heald frame motion. Mathematical models are then used to establish correlations between heald frame motion and cam profile coordinates, enabling machine optimization. In order to assess the influence of errors in cam profiles on heald frame motion, simulations are conducted using the Monte Carlo method. The study concludes that both systematic and random errors have a significant impact on heald frame movement, which in turn affects machine performance and weaving quality. By conducting a comparative analysis, the study provides guidance on minimizing errors in cam design, thus enhancing the precision of the heald frame. This research contributes to the field of textile machinery design and manufacturing.

A planar solid oxide fuel cell (SOFC) uses current collectors positioned between the cell and the interconnector. To address the cell deformation that occurs during extended operation of large SOFCs, we developed a novel flexible current collector made from a triple plain weave of Ni yarn. We characterized the properties of this triple plain weave and compared them with those of commercially available collectors using the Kawabata evaluation system at room temperature, as well as test methods for SOFC components at elevated temperatures. The triple plain weave demonstrated superior compression and recovery properties along the thickness direction compared to commercial collectors, such as single plain weaves and porous metals. The triple plain weave's flexibility was consistent at both low and high temperatures. Although the conductivity of the triple plain weave was lower than that of other collectors, the SOFC's output performance with this weave was higher than that with a single plain weave. Thus, triple plain weaves can enhance SOFC cell size and extend their lifespan.

For this study, we investigated the water absorption, hygroscopicity, and antibacterial properties of oxidized and chlorinated wool. Isothermal water vapor adsorption curve measurements were also conducted identically. The moisture absorption rate was determined by the constant volume method in the adsorption direction from relative humidity 0 %R.H. to around 90 %R.H. at an adsorption temperature of 20 °C. The size increased in the order of oxidation-treated wool and untreated wool, which matched the state of scale retention. Staphylococcus aureus was cultured for 18 hr using the bacterial liquid absorption method. Also, the number of bacterial cells was found using the pour plate culture method. The antibacterial activity value calculated using untreated wool as a control sample was 2.0 for redox wool and 0.4 for chlorinated wool, indicating that the redox wool exceeded the antibacterial standard.

The composite materials envisioned in this study were fiber-reinforced woven composites, which were composed of fibers as the reinforcement and resin as the matrix. Fiber-reinforced thermoplastic woven composites had high productivity, high toughness, and excellent recyclability because the thermoplastic resin was inexpensive and can be formed in a short period of time. When spread tow were used, it was desirable to reduce void generation and impregnation time during resin impregnation. It was very important to evaluate and understand the mechanical properties and damage mechanisms in advance to ensure the safety and reliability of the structure. However, the woven structure of fiber bundles was complex, and various damage forms such as resin cracks in the matrix, cracks in the fiber bundle, and fiber breakage occur, making damage evaluation difficult. In this study, to investigate the damage evolution behavior of thermoplastic woven CFRP with spread tows, an analysis with the mesh superposition method was proposed and the numerical results were compared with the conventional method. As a result, we believed that the mesh superposition method was useful because the effort required for model creation can be reduced in models with thinner layer thicknesses in the mesh superposition analysis compared to the conventional analysis.

Filaments used in textile products have many design parameters such as length, diameter, tip shape, material properties, etc. In order to design and develop the products efficiently that satisfy the desired functions, it is important to estimate the mechanical properties of filaments with various design parameters and to quantify the effects of design parameters on the mechanical behavior. In this study, we focused on as one of the design parameters of textile products, and evaluated the effects of this parameter on the mechanical properties of filaments under the sliding behavior based on the numerical and experimental approach. The results had shown that the difference in the tip shape of filaments affects the load value applied to the contacting body. It was also shown that the difference in the tip shape affected the deformation behavior. The difference of the tip shape was caused by the strain energy density of filaments during sliding movement. We believed that the results obtained in this study would be useful for the design and development of textile products efficiently.

Our previously proposed path simulation method of carrier on a multi-braider was used to determine the initial arrangement of carriers to make a braid with a branch-merge structure and fabricate a prototype braid. However, the prototype had a small braiding angle, and the structure of the branch-merge switching part was not well-formed. To address this, we investigated the relationship between the yarn feed amount from the carrier moving on the multi-braider and the carrier's yarn length compensating mechanism. We proposed an improved compensating mechanism to prepare a braid with a larger braiding angle. The resulting braid was found to have a well-formed branch-merge structure.

Braiding technology is attracting attention as a forming method for fiber-reinforced composite preforms. The square braider called the multi-braider can produce braiding preforms with various cross-sectional shapes. In the multi-braider, as the number of carriers increases and the carrier paths become more complex, it becomes more difficult to think about how to prevent carriers from colliding with each other. Therefore, the purpose of this paper is to develop simulation software for efficiently designing the carrier paths on the multi-braider when manufacturing a braiding preform with complex structure. We developed a simulator for the behavior of carriers when horn gears rotate continuously, using the carrier’s initial position and path or track as input values. The collisions can be identified in advance because the simulator indicates an error if the input values are not suitable. By introducing the carrier track simulation for the multi-braider, the work time to devise carrier paths and arrangements could be reduced to 1/3 for simple carrier paths and to less than 1/4 for complex carrier paths, making it possible to perform initial carrier placement efficiently. The results of this research will also improve the efficiency of design on the carrier’s initial placement and track and the safety of multi-braider operation.

During the production of synthetic fiber, a winder is used to wind the yarn, and the high-speed rotation of the package causes an increase in windage power due to high resistance from the surrounding air. However, to reduce costs of yarn production, it is important to improve energy consumption. Therefore, it is necessary to investigate the winder flow field using computational fluid dynamics(CFD)and reduce the windage power. In previous studies, simulations were performed using a model of the entire winder, however, the details on the flow field around the package were unknown. In this study, a touch-roll mechanism was incorporated into a simplified model to reduce the computational cost, and the flow field around the package was analyzed. The mechanism of increased windage was investigated to quantitatively determine the effective factors that reduce windage power by focusing on the flow field on the package surface layer that directly affects the windage. The results showed that incorporating the touch-roll mechanism had a significant effect on the windage power loss and the flow field, and that the increase in windage loss was observed particularly on the edge faces of the packages.