Study of the optimization of embroidery design parameters for the Technical Embroidery Machine: derivation of the correlation between thread consumption and electrical resistance

The smart textile industry has become increasingly interested in textile products with electronic functions. In these smart textile products, sensing and data communication are conducted through conductive circuits by conductive threads. In embroidery technology that uses conductive threads as the material for the conductive line as a circuit, their resistance is an important factor when designing a product. The main purpose of this study was to derive an equivalent circuit model and a calculation equation for the consumption of conductive threads according to the embroidery design parameters. The effects of the embroidery design parameters on the appearance and electrical characteristics of the conductive line were also analyzed. The appearance and electrical characteristics of the embroidered conductive line were different when the embroidery design parameters were not the same. The calculation equation for the consumption of conductive threads could establish a quantitative system that could indicate the line resistance of an embroidered conductive line using the embroidery design parameters and the given thread resistance.

The equivalent resistance model of double-layer embroidered conductive lines on nonwoven fabric

To reveal the engineering relationship among the electrical properties of embroidered conductive lines, the electrical properties and arrangements of conductive yarns, it is necessary to establish their equivalent resistance model. Embroidered conductive lines in textiles are usually fabricated by single-layer (conductive and nonconductive yarn used as upper and lower yarn) or double-layer embroidery technology (conductive yarns used as upper and lower yarn). Several researchers have proposed the simple resistance model for single-layer embroidered conductive line based on geometric structure of single conductive yarn in fabric. However, the double-layer conductive line has the contact resistance periodically interlaced by the upper and lower conductive yarns, and it made its equivalent circuit different from that of single-layer conductive line. In this work, a geometric model was built to describe the trace of conductive yarn in fabric, and in combination with Wheatstone Bridge theory, was applied to establish the equivalent resistance models of double-layer conductive lines with a certain width, consisted of various courses. First, the equivalent resistance model of double-layer conductive lines consisting of single course was proposed to calculate the contact resistance. Then, to obtain the electrical resistance of double-layer conductive lines with a certain width, the equivalent resistance model was extended from single course to multiple courses ([Formula: see text]). Finally, to validate the proposed equivalent resistance model, double-layer conductive lines with different embroidery parameters (stitch length and stitch spacing) on nonwoven fabric were fabricated and evaluated. The experimental results revealed that the proposed model accurately predicted the resistances of double-layer conductive lines.

PHYSICO-MATHEMATICAL APPARATUS OF THE MOVEMENT OF A TWO-PHASE MICRO-SOLUTION BY A MILK-CONDUCTIVE LINE

An analysis of domestic and foreign studies has shown that the efficiency of washing depends on the complex influence of such factors as temperature, velocity of the flow of a two-phase washing solution, its concentration, circulation duration, etc. Therefore, the modes of milking milk lines and the equipment parameters for this purpose require justification. The quality of the flushing of the milk line is influenced by the two-phase washing solution's current regimes. Therefore, it is necessary to theoretically investigate the process of moving a two-phase washing solution through the milk pipeline to begin with. To implement numerical simulation of the process of flushing the milk line of the milking unit, it is necessary to develop a physical and mathematical apparatus for the movement of a two-phase detergent solution on it. As a result of theoretical studies, the physics and mathematical apparatus of motion of a two-phase washing solution on the milk pipeline line is developed, which is based on the equations of the principle of superposition of forces and as a consequence of pressures, continuity of the flow, laws of conservation of mass, momentum and energy.

A Simple, Reusable and Low-Cost LVDT-Based in Situ Bolt Preload Monitoring System during Fastening for a Truck Wheel Assembly

The aim of this study is to design and test a new, simple, and reusable linear variable differential transformer (LVDT)-based in situ bolt preload monitoring system (L-PMS) during fastening of a truck wheel assembly. Instead of measuring the elongation of a bolt, the distance between the end surfaces of both the bolt and nut was monitored via the L-PMS. The distance obtained from the L-PMS was experimentally correlated with the actual preload measured by a washer-type load cell. Since the variation of the distance is related to the stiffness of the bolt and clamped parts, a finite element analysis was also conducted to predict the sensitivity of L-PMS. There was a strong linear relationship between the distance and bolt preload after the bolt and nut were fully snugged. However, a logarithm-shaped nonlinear relationship was irregularly observed before getting snugged, making it difficult to define a clear relationship. In order to tackle this issue, an arc-shaped conductive line was screen-printed onto the surface of the clamped parts using a conductive carbon paste. The results show that a resistance variation of the conductive line during fastening enables to determine the snug point, so the L-PMS combined with resistance measurement results in an approximately ±6% error in the measurement of bolt preload. The proposed L-PMS offers a simple but highly reliable way for measuring bolt preload during fastening, which could be utilized in a heavy-truck production line.

A Flexible Tactile Sensor with Irregular Planar Shape Based on Uniform Electric Field

Tactility is an essential perception for intelligent equipment to acquire external information. It can improve safety and performance during human-machine interactions. Based on the uniqueness theorem of the electrostatic field, a novel flexible film tactile sensor that can detect contact position and be made into any plane shape is proposed in this paper. The tactile sensor included an indium tin oxide (ITO) film, which was uniformly coated on the polyethylene terephthalate (PET) substrate. A specially designed strong conductive line was arranged along the edge of the flexible ITO film, which has weak conductivity. A bias excitation was applied to both ends of the strong conductive line. Through the control of the shape of the strong conductive line, a uniform electric field can be constructed in the whole weak conductive plane. According to the linear relationship between position and potential in the uniform electric field, the coordinate of the contact position can be determined by obtaining the potential of the contact point in the weak conducting plane. The sensor uses a three-layer structure, including an upper conductive layer, an intermediate isolation layer, and a lower conductive layer. A tactile sensor sample was fabricated. The experiment results showed that the principle of the tactile sensor used for the contact position detection is feasible and has certain precision of position detection. The sensor has good flexibility, and can be made into any plane shape, and has only four wires. It is capable of covering large areas of robot arms, and provides safety solutions for most robots.

Flexoelectric Vibration Control of Plates by Line Electrodes

The electric polarization induced by the strain gradient is the direct flexoelectric effect; the mechanical stress/strain induced by the electric field gradient is the converse flexoelectric effect. Accordingly, flexoelectric sensors and actuators are respectively designed to monitor the structural dynamic behavior and to control the structural vibration. In this study, a line-electrode induced flexoelectric actuation is designed to control the plate vibrations. A flexoelectric layer laminated on the thin plate is used as a distributed actuator. The bottom surface of the flexoelectric actuator is a common electrode and the top surface is driven by a conductive line to generate an inhomogeneous electric field. Based on the converse flexoelectric effect, the electric filed gradient induces mechanical stresses in the flexoelectric layer resulting in induced bending moments to the plate structure. With the control moment imposed on the plate, flexoelectric vibration control of the plate is evaluated in this study. The objective of this study is to explore the modal control effects of the plate by the conductive line excitation. For a plate with two opposite sides simply supported and the other two are free (SS-F-SS-F), vibration control response of the plate is studied when the conductive line locates parallel to the y width direction. Then, independent modal control effects (i.e., the induced or controllable displacements by the flexoelectric actuator) are evaluated for the modes (1,1), (1,2), (1,3), (2,1) and (3,1) with different line actuation locations. Control effects of the conductive line location to various plate modes are explored and results show that the optimal conductive line location differs for different plate modes. When the FF width decreases to far less than the SS length, the SS-F-SS-F plate is degraded to a simply supported beam. Then, control effects for modes (1,1), (2,1) and (3,1) with different conductive line locations are discussed. The results are compared with the control effect derived directly by the simply supported beam theory. Thus, this study suggests that plate vibration can be controlled by the line-electrode induced converse flexoelectric effect. Conductive line locations are critical to control of various plate modes.

A ‘point–line–point’ hybrid electrocatalyst for bi-functional catalysis of oxygen evolution and reduction reactions

A hybrid electrocatalyst with ‘active point–conductive line–active point’ connections was proposed and exhibited superb bi-functional reactivity for both oxygen reduction and oxygen evolution reactions.