Design and manufacture of three-dimensional auxetic warp-knitted spacer fabrics based on re-entrant and rotating geometries

2021 ◽  
pp. 004051752110372
Author(s):  
Chang Yuping ◽  
Yanping Liu ◽  
Zhao Shuaiquan ◽  
Hu Hong
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Fabric Structure ◽  
Spacer Fabric ◽  
Wide Range ◽  
Yarn Guide ◽  
Tensile Strains ◽  
Spacer Fabrics ◽  
Fabric Structures ◽  
Design And Manufacture

Warp knitting technology is a fabric-forming technologies that is very suitable to fabricate three-dimensional (3D) auxetic fabrics due to its high efficiency and powerful pattern designing possibilities. In this study, two typical auxetic geometries, namely the re-entrant hexagonal network and rotating square solids, were selected as the design prototypes for the design and manufacture of 3D warp-knitted spacer fabrics. While two 3D warp-knitted spacer fabric structures with representative units of different sizes designed based on the re-entrant hexagonal geometry were manufactured by using a RD7 double needle bar Raschel machine with seven yarn guide bars, two 3D jacquard warp-knitted spacer fabrics with different base fabric structures designed based on the rotating squares geometry were fabricated by using a RDPJ4/2 double needle bar jacquard machine with two ground yarn guide bars and four jacquard guide bars. The Poisson’s ratios of these 3D warp-knitted fabrics in the course direction and wale direction were evaluated respectively through constant-rate tensile tests. The results revealed that the re-entrant hexagonal fabric structure with double chain stitches has auxetic behavior across a wide range of tensile strains along the course direction, while the rotating square fabric structure with elastic chain stitches as the base is auxetic within a narrow range of tensile strains along the wale direction. The study provides an alternative method to directly produce auxetic warp-knitted spacer fabrics through a single knitting process instead of using an additional post-compression and heat-setting process.

scholarly journals A NEW TEST METHOD TO MEASURE THE COMPRESSIBILITY OF SPACER FABRICS

2019 ◽  
Vol 2019 ◽  
pp. 140-143
Author(s):  
Musa KILIC ◽  
Gonca BALCI KILIC ◽  
Murat DEMIR ◽  
Gulsah CELIK ◽  
Izzet Onal BUGDUZ ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Three Dimensional ◽  
Test System ◽  
Test Methods ◽  
Test Method ◽  
Dimensional Structure ◽  
Spacer Fabric ◽  
The Difference ◽  
Spacer Fabrics ◽  
Fabric Structures

Spacer fabric is a three-dimensional structure that obtained by the connection of two parallel fabric surfaces with the connection threads. Spacer fabrics are widely used for their several functional advantages that they provide unlike conventional fabrics. Compressibility is one of the important functional parameters for these fabric structures. The compressibility values of the spacer fabrics are measured based on the ISO 3386-1 standard. However, this standard is used for structures that have non-axial shear during compression such as foam, sponge and so on. It is thought that this standard is not suitable for spacer fabric structures due to the shear deformation which occurs during the measurement of compressibility. For this purpose, as in accordance with spacer fabrics end-use area, a new test system been proposed to measure of compressibility that prevents shear during the test. Thus, it is aimed to prevent the shear deformation and the deviant results obtained during the test. Within the scope of the study, the compressibility properties of spacer fabric structures, which have undergone different thicknesses and different finishing processes, were measured according to both ISO 3386-1 and the new proposed test method. When the results were compared, it was observed that the results obtained in the new proposed test setup were higher and the difference between the measured results according to both test methods was statistically significant for α = 0.05.

Flat-knitted innovative three-dimensional spacer fabrics: a competitive solution for lightweight composite applications

2011 ◽  
Vol 82 (3) ◽  
pp. 288-298 ◽  
Author(s):  
MD Abounaim ◽  
Chokri Cherif
Keyword(s):  
Mechanical Properties ◽  
Sensor Networks ◽  
Health Monitoring ◽  
Complex Shape ◽  
Three Dimensional ◽  
Surface Layers ◽  
Fabric Structure ◽  
Spacer Fabric ◽  
Processing Step ◽  
Spacer Fabrics

Flat-knitted spacer fabrics offer a strong potential for complex shape preforms, which could be used to manufacture composites with reduced waste and shorter production times. A reinforced spacer fabric made of individual surface layers and joined with connecting layers shows improved mechanical properties for lightweight applications, such as textile-based sandwich preforms. We report the development of flat-knitted multi-layered innovative three-dimensional (3D) spacer fabrics from hybrid yarns consisting of glass and polypropylene filaments. Moreover, for structural health monitoring of composites, sensor networks could be created into a 3D spacer fabric structure in a single processing step through innovative integration of functional yarns.

scholarly journals STRUCTURAL DEVELOPMENT AND RESEARCH OF TECHNOLOGICAL PARAMETERS OF MACHINES FOR CENTRIFUGAL -PLANETARY VIBRATION TREATMENT

2020 ◽  
pp. 41-50
Author(s):  
Leonid Yaroshenko ◽  
Igor Kupchuk ◽  
Mykhailo Zamrii
Keyword(s):  
High Efficiency ◽  
Metal Removal ◽  
Three Dimensional ◽  
High Hardness ◽  
Working Environment ◽  
Repeated Loading ◽  
Structural Development ◽  
Technological Parameters ◽  
Advantages And Disadvantages ◽  
Wide Range

The paper analyzes current state and prospects of further development of technology and equipment for mechanization and automation of finishing and cleaning of details. It is stated that the most effective for this purpose are the methods of abrasive machining, which include bulk galvanizing, vibration, centrifugal-rotary and centrifugal-planetary processing. These methods reduce the complexity and cost of processing, which in some cases reaches 20% of the total cost of manufacturing parts. Each of these methods has a different level of efficiency, certain advantages and disadvantages, the level of versatility and scope of effective application. The processes of vibration processing are quite deeply studied, for its industrial mass-produced technological equipment, but they have certain shortcomings that limit their use for further widespread implementation. Centrifugal-rotary processing is a more productive process of three-dimensional finishing and cleaning treatment, but its scope is limited by the possibility of processing parts that are not complex, usually flat. The most productive methods of finishing and cleaning of details include centrifugal-planetary volume processing which high efficiency is caused by repeated loading of particles of working load by inertial forces that creates preconditions for the solutions of a wide range of technological problems, for example, processing of details of difficult form, small weight and the sizes from materials of high hardness or viscosity that represents a serious problem for other methods of volume processing. The constructive scheme is offered in the work and the influence of the composition of the abrasive free-granular working environment on the productivity of the machine for centrifugal-planetary processing of details is investigated. The kinetics of metal removal from the surface of machined parts using different types of abrasive working environment is analyzed. The results of comparative machining of parts in a torus vibrating machine and a machine for centrifugal-planetary machining are given. It is shown that the simultaneous use of centrifugal-planetary and vibration processing methods allows to increase the intensity of the process while ensuring high quality machining of parts of relatively complex shape. The constructive scheme of the machine which allows to implement the specified combined method of processing is offered and described.

scholarly journals Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

2015 ◽  
Vol 15 (3) ◽  
pp. 191-197 ◽  
Author(s):  
Xiaoying Li ◽  
Gaoming Jiang ◽  
Xiaolin Nie ◽  
Pibo Ma ◽  
Zhe Gao
Keyword(s):  
Tensile Stress ◽  
Tensile Properties ◽  
Dimensional Stability ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Weft Direction ◽  
Aramid Fibres ◽  
Spacer Fabric ◽  
Fabric Deformation ◽  
Spacer Fabrics

AbstractThis paper introduces a knitting technique for making innovative curved three-dimensional (3D) spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction) were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns), and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

scholarly journals Self-organized phase-transition lithography for all-inorganic photonic textures

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Bo Zhang ◽  
Dezhi Tan ◽  
Zhuo Wang ◽  
Xiaofeng Liu ◽  
Beibei Xu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Efficiency ◽  
Three Dimensional ◽  
Research Direction ◽  
Structural Features ◽  
Ultrafast Laser ◽  
Material System ◽  
Self Organized ◽  
Wide Range ◽  
Matter Interaction

AbstractRealizing general processing applicable to various materials by one basic tool has long been considered a distant dream. Fortunately, ultrafast laser–matter interaction has emerged as a highly universal platform with unprecedented optical phenomena and provided implementation paths for advanced manufacturing with novel functionalities. Here, we report the establishment of a three-dimensional (3D) focal-area interference field actively induced by a single ultrafast laser in transparent dielectrics. Relying on this, we demonstrate a radically new approach of self-organized phase-transition lithography (SOPTL) to achieve super-resolution construction of embedded all-inorganic photonic textures with extremely high efficiency. The generated textures exhibit a tunable photonic bandgap (PBG) in a wide range from ~1.3 to ~2 μm. More complicated interlaced textures with adjustable structural features can be fabricated within a few seconds, which is not attainable with any other conventional techniques. Evidence suggests that the SOPTL is extendable to more than one material system. This study augments light–matter interaction physics, offers a promising approach for constructing robust photonic devices, and opens up a new research direction in advanced lithography.

scholarly journals Dielectric Metalens: Properties and Three-Dimensional Imaging Applications

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4584
Author(s):  
Sun-Je Kim ◽  
Changhyun Kim ◽  
Youngjin Kim ◽  
Jinsoo Jeong ◽  
Seokho Choi ◽  
...  
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Optical Systems ◽  
Functional Improvement ◽  
Depth Information ◽  
Optical Components ◽  
Three Dimensional Imaging ◽  
Wide Range ◽  
Optical Dielectric ◽  
Optical Focusing

Recently, optical dielectric metasurfaces, ultrathin optical skins with densely arranged dielectric nanoantennas, have arisen as next-generation technologies with merits for miniaturization and functional improvement of conventional optical components. In particular, dielectric metalenses capable of optical focusing and imaging have attracted enormous attention from academic and industrial communities of optics. They can offer cutting-edge lensing functions owing to arbitrary wavefront encoding, polarization tunability, high efficiency, large diffraction angle, strong dispersion, and novel ultracompact integration methods. Based on the properties, dielectric metalenses have been applied to numerous three-dimensional imaging applications including wearable augmented or virtual reality displays with depth information, and optical sensing of three-dimensional position of object and various light properties. In this paper, we introduce the properties of optical dielectric metalenses, and review the working principles and recent advances in three-dimensional imaging applications based on them. The authors envision that the dielectric metalens and metasurface technologies could make breakthroughs for a wide range of compact optical systems for three-dimensional display and sensing.

Simulation of plate compression behavior of warp-knitted spacer fabrics based on geometry and property parameters

2018 ◽  
Vol 89 (6) ◽  
pp. 1051-1064 ◽  
Author(s):  
Fengxin Sun ◽  
Mingying Ma ◽  
Xingxing Pan ◽  
Gui Liu ◽  
Shu Yang ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Strain Curve ◽  
Dimensional Structure ◽  
Bending Angle ◽  
Compression Behavior ◽  
Compression Property ◽  
Spacer Fabric ◽  
Spacer Fabrics

The plate compression property of warp-knitted spacer fabrics greatly determines their industrial application in cushions and mattresses, which can be regulated by the structure and property of spacer filaments of spacer fabrics. To better meet application requirements, this paper detailed a study on the relationships between the geometry and property parameters of spacer filaments and the plate compression property of spacer fabrics. A three-dimensional structure model was firstly developed using the finite element method based on a typical spacer fabric. The model shows a satisfactory prediction of the compression force–strain curve of the spacer fabric compared with the corresponding experimental curve. Consequently, the effects of geometry parameters, including height, diameter, arrangement density and bending angle of spacer filaments, and Young’s modulus of the filaments on the compression behavior of spacer fabrics were investigated using the validated model by adjusting the corresponding geometry and property parameters. The stress nephogram and stress distribution along the filaments at compression strain 0.6 were analyzed to discover the deformation mechanism of spacer filaments under compression. It was found that the spacer fabric with smaller filament height, courser filament diameter, larger bending angle, higher arrangement density and Young’s modulus of filaments had higher compression resistance. This study is useful to optimize the performance of spacer fabrics in design and manufacturing by purposefully tuning the geometry and property parameters.

scholarly journals Mixing Performance of a Cost-effective Split-and-Recombine 3D Micromixer Fabricated by Xurographic Method

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 786 ◽  
Author(s):  
Ramezan Ali Taheri ◽  
Vahabodin Goodarzi ◽  
Abdollah Allahverdi
Keyword(s):  
High Efficiency ◽  
Molecular Diffusion ◽  
Low Cost ◽  
Three Dimensional ◽  
Cost Effective ◽  
Reynolds Numbers ◽  
Mixing Performance ◽  
Wide Range ◽  
Fluid Layers ◽  
Passive Micromixer

This paper presents experimental and numerical investigations of a novel passive micromixer based on the lamination of fluid layers. Lamination-based mixers benefit from increasing the contact surface between two fluid phases by enhancing molecular diffusion to achieve a faster mixing. Novel three-dimensional split and recombine (SAR) structures are proposed to generate fluid laminations. Numerical simulations were conducted to model the mixer performance. Furthermore, experiments were conducted using dyes to observe fluid laminations and evaluate the proposed mixer’s characteristics. Mixing quality was experimentally obtained by means of image-based mixing index (MI) measurement. The multi-layer device was fabricated utilizing the Xurography method, which is a simple and low-cost method to fabricate 3D microfluidic devices. Mixing indexes of 96% and 90% were obtained at Reynolds numbers of 0.1 and 1, respectively. Moreover, the device had an MI value of 67% at a Reynolds number of 10 (flow rate of 116 µL/min for each inlet). The proposed micromixer, with its novel design and fabrication method, is expected to benefit a wide range of lab-on-a-chip applications, due to its high efficiency, low cost, high throughput and ease of fabrication.

scholarly journals An Experimental Study of Compression Behavior of Warp-knitted Spacer Fabric

2014 ◽  
Vol 9 (2) ◽  
pp. 155892501400900
Author(s):  
Yanping Liu ◽  
Hong Hu
Keyword(s):  
Experimental Study ◽  
Displacement Curve ◽  
Compression Tests ◽  
Compression Behavior ◽  
Compression Load ◽  
Fabric Structure ◽  
Spacer Fabric ◽  
Compression Mechanism ◽  
Impact Protection ◽  
Spacer Fabrics

This paper presents an experimental study of the compression behavior of a typical warp-knitted spacer fabric which is specially developed as a cushioning material for human body protection. The fabric has a highly heterogeneous and discontinuous structure and exhibits a complicated compression behavior. Different test boundary conditions and sample sizes were first adopted to conduct compression tests of the fabric. Then, the compression behavior of the fabric was analyzed based on its compression load-displacement curve obtained under a selected test condition. The potential compression mechanism of the fabric was identified with support of the image analysis of the fabric structure at different compression stages. The study provides some useful information for designing warp-knitted spacer fabrics for impact protection.

Spacer fabric-based exuding wound dressing – Part I: Structural design, fabrication and property evaluation of spacer fabrics

2016 ◽  
Vol 87 (12) ◽  
pp. 1469-1480 ◽  
Author(s):  
Yadie Yang ◽  
Hong Hu
Keyword(s):  
Structural Design ◽  
Wound Dressing ◽  
Air Permeability ◽  
Fabric Structure ◽  
Property Evaluation ◽  
Spacer Fabric ◽  
Water Vapor Transmission ◽  
Different Types ◽  
New Type ◽  
Spacer Fabrics

Exuding wound dressing is used to help wound healing. Currently, commercial dressings for heavily exuding wounds still have some drawbacks, such as poor integrity, poor air permeability, low water vapor transmission, and the need for a secondary dressing on the top. To overcome these drawbacks, a new type of wound dressing based on the three-layer spacer fabric structure is proposed in this study. The study includes two parts. The first part focuses on the design, fabrication, and property evaluation of spacer fabrics that can be used for wound dressing. Twelve different types of spacer fabrics were first fabricated. Then, different properties, including wettability, absorbency, permeability, and thermal insulation, were tested and evaluated. A statistical analysis was also conducted to evaluate the effects of structural and yarn parameters on the properties of the spacer fabrics. Based on the testing results, two suitable spacer fabrics were finally selected as the basis for wound dressing material. It is expected that this study could promote the application of spacer fabrics in the medical area.

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