Mei-yu Chen

Electromagnetic Shielding Effectiveness of Fabrics with Metallized Polyester Filaments

A preliminary study of the electromagnetic shielding effectiveness (EMSE) using metal coating films and a vacuum evaporation deposition technique with the woven fabrics made of metal/PET filaments is presented. Using coaxial transmission equipment, the EMSE of these films and fabrics was measured in the frequency range 2250—2650 MHz. The experimental results indicate that different coating materials have different EMSE, with a thicker coating film having a higher EMSE. In addition, a woven fabric with lower aperture ratio made from metal/polyethylene terephthalate (PET) filaments has higher EMSE, and the electromagnetic shielding of polarized electromagnetic waves possesses orientation effects. The paper provides theoretical guidance for designing flexible electromagnetic shielding products.

Color Variation on Spun-dyed Polyester Filaments during Processing

In this study, the color variation of spun-dyed polyester filaments was systematically investigated using various processing technology parameters including linear density, velocity of cross-flow air, different processing ways and different textured technology parameters. The results showed that these parameters had varying degrees of influence on the color of spun-dyed polyester filament in processing. The degrees of color variation were expressed using the CIE1976 L*a*b* system. As a result, it provided an important theoretical guidance for working out actual production technology and controlling color quality of spun-dyed polyester filaments based on actual industrial equipment and technological conditions.

Compressive deformation and load of a spacer filament in a warp-knitted spacer fabric

The compressive deformation and load of a spacer filament in a warp-knitted spacer fabric was analyzed theoretically in this work. It was found that the compression process of the spacer filament can be divided into four stages, including a Stiff Stage, an Elastic Stage, a Restful Stage, and an Ineffective Stage. Based on the theoretical analysis of the compressive displacement and the radius of the spacer filament at different stages, as well as the bending moment of the spacer filament during compression, the relationship between the critical compressive load at different stages and the structural parameters of the spacer filament in a warp-knitted spacer fabric was found. Furthermore, plane plate compression experiments for spacer filaments were designed and tested to verify the correctness of the theoretical analysis.

The Structure of Compact Yarn

A novel method for reconstruction of yarn structure was developed for the investigation of the structure of compact yarn. The structure characteristics derived from two reconstructed yarns with the same specifications and constituent components presented considerable agreement with that of real yarn structure.A novel method for reconstruction of yarn structure was developed for the investigation of the structure of compact yarn. The structure characteristics derived from two reconstructed yarns with the same specifications and constituent components presented considerable agreement with that of real yarn structure.

Visual Masking Performance of a Fabric

In this study, we investigated the main factors affecting the visual masking performance of a fabric, including the illumination level of the target, the cover factor of the fabric, the distance between the fabric and the target, and the illumination level of the fabric. It was found that among these four factors, the illumination level of the target had a significant effect on the visual masking performance. The masking performance of the fabric could be improved by decreasing the illumination level of the target and by increasing the illumination level of the fabric itself. For a nylon monofilament plain fabric, the masking performance of the fabric could be improved by increasing the cover factor of the fabric. In addition, the masking performance of a fabric could be improved slightly by increasing the distance between the fabric and the target.

Electrical property evolution of a metallic film deposited on polyethylene terephthalate substrate during tensile deformation

The electrical property evolution of a metal/polyethylene terephthalate (PET) composite during tensile deformation was theoretically analyzed in this work. It was found that the resistance variation of a metal/PET composite during tensile deformation falls into two parts: before a crack appearance and after a crack appearance. Before a crack appears on the coated metal layer, the resistance variation complies with Ohm’s law. After that, the resistance variation of the metal/PET composite, on the whole, correlates with the elongation rate of the metal/PET composite in an exponent relation. In addition, the resistance variation of the Al/PET composite during tensile deformation was tested for verifying the correctness of the theoretical analysis.

Optimization of spacer filament parameters by compressive property variation

The mechanical property of a warp-knitted spacer fabric during compression results mainly from the contribution of the spacer filaments in the fabric. So, the mechanical property of a spacer filament during compression can predict that of the designed spacer fabric during compression, and then provides a scientific basis for the designers. In this work, a new method for measuring the mechanical properties of a spacer filament during compression was proposed to simulate the compression situation of a filament in a warp-knitted spacer fabric. The paper focuses on the mechanical property variation of a spacer filament with different parameters during compression. In particular, we investigated the effect of different parameters of the spacer filament on the supporting and restful properties of the corresponding spacer fabric, which is closely related to consumer concerns. Furthermore, based on the analysis of the mechanical property variation of a spacer filament with different parameters during compression, the scheme of the spacer filament parameters designed in this work was optimized.

Factors Affecting on the Electricity Properties of a Metal/Pet Composite during Tensile Deformation

The effects of different factors on the electrical properties of a well-bonded metal/PET composite during tensile deformation were systematically analyzed, including metal materials, metal coating film thickness and environmental temperature. It was found that, before a crack appearance in the coated metal film, the critical elongation of a well-bonded metal/PET composite depended on the differences of modulus and Poissons ratio between the coated metal material and PET substrate. After cracking, the metal/PET composites with different metal films showed different elongations when there was a sudden increase in the resistance of the metal/PET composite; the thicker the metal film deposited on PET substrate was, the lower resistance the metal/PET composite had. The thickness of metal film had no obvious effect on the critical elongation of the metal/PET composites. In addition, the resistance of the metal/PET composite increased with the increasing environmental temperature.

Non-Fick effect of transient water transport in woven fabrics

This study investigated a new phenomenon of liquid water transport in woven fabrics by using a specially-designed liquid water transport detecting device. It was found that within 6 mm space from liquid water resource, transient transport of liquid water in a woven fabric appears to have non-Fick effect, that is, liquid water transport in a woven fabric processes obvious transient shock effect. After this transient period, water transport in the fabric follows the classical mass transfer theory, and tends to maintain a constant rate. The non-Fick effect of the water transport varied with fabric densities and yarn twists. In general, the lower the fabric density and the yarn twist are, the more obvious the non-Fick effect is. The non-Fick effect of transient transports of liquid water also behaved differently for fabrics made of different fiber materials.