A Study on Compression Behavior of Warp Knitted Spacer Fabrics

2011 ◽  
Vol 332-334 ◽  
pp. 1036-1039
Author(s):  
Xiao Fang Guo ◽  
Hair U Long
Keyword(s):  
Surface Structure ◽  
Inclination Angle ◽  
Compression Rate ◽  
Compression Tests ◽  
Apparent Effect ◽  
Compression Behavior ◽  
Spacer Fabric ◽  
Spacer Fabrics ◽  
Chinese Standard ◽  
Compression Resistance

The influences of inner layer′s (spacer yarn′s) pattern, surface structure of fabric, thickness, and spacer yarn′s diameter on compression resistance of warp knitted spacer fabric were investigated in the study. The compression tests involving 10 samples were carried out by TexLab Precision Instruments CT250 based on Chinese standard FZ/T01051.2-1998. The results show that inner layer′s pattern and surface structure affect the compression resistance of spacer fabric by changing the inclination angle of spacer yarn, the closer spacer yarn keep vertical, the better compression resistance of fabric. The laws of force exerted on spacer yarn followed by fabric′s thickness differ according to compression rate, the compression resistance increases as the thickness increases when the deformation of fabric is small (less than 4.90%), but decreases when the deformation is large enough (more than 19.20%). The diameter of spacer yarn has apparent effect on compression resistance, and the fabric with finer spacer yarns has lower compression resistance.

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.

scholarly journals An Experimental Study Of The Compression Properties Of Polyurethane-Based Warp-Knitted Spacer Fabric Composites

2017 ◽  
Vol 17 (3) ◽  
pp. 199-205 ◽  
Author(s):  
Si Chen ◽  
Xue-pei Zhang ◽  
Hong-xia Chen ◽  
Xiao-ping Gao
Keyword(s):  
Energy Absorption ◽  
Inclination Angle ◽  
Stress Level ◽  
Layer Structure ◽  
Structural Parameters ◽  
Fabric Thickness ◽  
Compression Properties ◽  
Spacer Fabric ◽  
Fabric Composites ◽  
Spacer Fabrics

AbstractThe present work has reported the compression properties of polyurethane-based warp-knitted spacer fabric composites (PWSF). In order to investigate the effect of structural parameters of fabric on the compression performance of composites, a series of warp-knitted spacer fabrics (WSF) with different structural parameters including spacer yarn inclination angle, thickness, fineness of spacer yarns, and outer layer structure have been involved. The produced composites have been characterized for compression properties. The energy-absorption performance during the compression process has been determined as a function of the efficiency and the compression stress obtained from compression tests. The results show that the composites based on spacer fabrics having smaller spacer yarns inclination angle, higher fabric thickness, finer spacer yarn, and larger mesh in outer layers perform better with respect to energy-absorption properties at lower stress level, whereas at higher stress level, the best energy-absorption abilities are obtained in case of spacer fabrics constructed of larger spacer yarn inclination angle, lower fabric thickness, coarser spacer yarn, and smaller mesh in surface layers.

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.

A Newly Developed Clamping Device for the Tension/Compression Test at Various Strain Rates

2014 ◽  
Vol 626 ◽  
pp. 353-358
Author(s):  
Geun Su Joo ◽  
Min Kuk Choi ◽  
Hoon Huh
Keyword(s):  
Strain Rate ◽  
Sheet Metal ◽  
Metal Forming ◽  
Loading Condition ◽  
Strain Rates ◽  
Compression Tests ◽  
Compression Behavior ◽  
Compression Loading ◽  
Hardening Behavior ◽  
Clamping Device

The tension/compression hardening behavior is important in sheet metal forming processes because of complicated loading paths. Experimental methods to measure the tension/ compression behavior have not considered the effect of the strain rate although the strain rate is related to the hardening behavior of sheet metal. The tension/compression tests need to be conducted considering the strain rate to acquire accurate hardening behavior.This paper deals with an experimental technique to measure the tension/compression behavior of sheet metal at various strain rates. A new clamping device was developed to prevent a sheet specimen from buckling under compression loading condition. Compared to previous clamping devices, the clamping device was devised to uniformly impose a clamping force and easily measure the strain from side of a specimen. Tension/compression tests have been conducted at various strain rates for SPCC and DP590 with displacement of 10%. Hardening curves under the tension or compression loading condition were obtained and analyzed with respect to the strain rate.

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.

Mechanical properties of the surface membrane of lattice spacer-fabric flexible inflatable composites

2021 ◽  
pp. 004051752110466
Author(s):  
Tong Yang ◽  
Min Luo ◽  
Zhuanyong Zou ◽  
Pibo Ma
Keyword(s):  
Mechanical Properties ◽  
Surface Membrane ◽  
Composite Membranes ◽  
Vital Role ◽  
Specific Strength ◽  
Spacer Fabric ◽  
Bearing Loads ◽  
Spacer Fabrics ◽  
Woven Structure ◽  
Performance Research

The surface membrane plays a vital role in bearing loads of flexible inflatable composites. In this work, the mechanical properties of the upper and lower surfaces of inflatable composites and spacer fabrics were studied. It focused on the changes in mechanical properties of surfaces of spacer fabrics with different structures after coating and damage characteristics. The results show that the PVC resin improves the mechanical properties of the surface, which penetrates into the structure to make the yarns bond to each other and adhere to the resin on the surface. And compared with knitted structures, composite membranes with a woven structure have the characteristics of specific strength. This provides data accumulation for performance research of flexible inflatable composites, finite element calculation analysis, and the experimental reference for broadening the application in military pontoons and marching tents.

Experimental study and numerical simulation of uniaxial compression on artificial rock samples with Z-shaped fractures

2021 ◽  
Author(s):  
Tao Zhou ◽  
Haijun Chen ◽  
Liangxiao Xiong ◽  
Zhongyuan Xu ◽  
Jie Yang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Crack Length ◽  
Uniaxial Compression ◽  
Inclination Angle ◽  
Failure Surface ◽  
Peak Strength ◽  
Particle Flow Code ◽  
Compression Tests ◽  
Failure Characteristics ◽  
Change Trend

Abstract To study the influence of the inclination and length of Z-shaped fissures on the mechanical properties and failure characteristics of the rock mass, this study conducts a series of uniaxial compression tests on rock-like materials with prefabricated Z-shaped fractures. In addition, two-dimensional Particle Flow Code software is used to perform uniaxial compression numerical simulations. The results show that when the specified inclination angle γ (γ = 0°, 30° or 45°) of the parallel cracks on both sides remains unchanged, the peak strength and elastic modulus of the sample show an M-shaped change trend with an increase in the inclination angle β of the middle connection crack. When γ = 60° or 90°, however, the peak strength and elastic modulus of the sample show a trend of decreasing, increasing, and then decreasing as β increases. In addition, the peak strength and elastic modulus of the sample decrease with an increase in the crack length. The influence of crack length on the elastic modulus is less than that of compressive strength. Further, the main failure mode of specimens with Z-shaped cracks is determined to be tension–shear mixed failure manifested by crack propagation from the tip of the prefabricated crack to the upper and lower boundaries of the sample. As a result, a through failure surface is formed with the prefabricated crack, which destroys the sample.

Cushioning properties of weft-knitted spacer fabrics

2017 ◽  
Vol 88 (14) ◽  
pp. 1628-1640 ◽  
Author(s):  
Tong Zhao ◽  
Hairu Long ◽  
Tianqi Yang ◽  
Yanping Liu
Keyword(s):  
Human Body ◽  
Structural Parameters ◽  
Testing Machine ◽  
Three Dimensional ◽  
Structural Features ◽  
Practical Significance ◽  
Absorption Energy ◽  
Yarn Diameter ◽  
Spacer Fabrics ◽  
Compression Resistance

Three-dimensional spacer fabrics which have a sandwich structure are formed in a single knitting process without any additional joining treatment. They consist of two separate multifilament outer layers connected by arrays of spacer monofilaments. This paper presents an experimental study on the relationships between the cushioning properties and structural parameters of weft-knitted spacer fabrics in order to lay a foundation for the development of seamless shaped impact protectors for human body impact protection. Sixteen spacer fabrics of different structural parameters were knitted on a computerized flat knitting machine and tested on a universal mechanical testing machine. The cushioning properties of the spacer fabrics were analyzed in terms of their structural features, compression stress–strain curves, energy absorption, and compression resilience. It was found that multifilament fineness, spacer yarn diameter, and spacer yarn pattern should be matching in order to form effective binding structures between the outer layers and spacer monofilaments. The results also showed that spacer fabrics knitted with a shorter spacer yarn span distance, coarser monofilaments, and higher spacer yarn density have better compression resistance and absorption energy but inferior compression resilience if their binding structures are effective. This study has practical significance in promoting the application of this type of fabric as a cushion material for human body protection.

Prediction and analysis of compression behaviour of warp-knitted spacer fabric with cylindrical surface

2018 ◽  
Vol 48 (9) ◽  
pp. 1489-1504 ◽  
Author(s):  
Mrinal K Datta ◽  
B K Behera ◽  
Ashvani Goyal
Keyword(s):  
Human Body ◽  
Cylindrical Surface ◽  
Radius Of Curvature ◽  
Body Parts ◽  
Energy Effect ◽  
Compression Behaviour ◽  
Spacer Fabric ◽  
Medical Textile ◽  
Experimental Values ◽  
Spacer Fabrics

Nowadays, applications of spacer fabric cover wider areas of technical textile. It is used in the automotive textile, personal protective clothing, sports textile, foundation garments, pads for swimwear, buffer clothing, medical textile etc. It does possess good recovery to compression, high bulk with relatively lightweight and very good moisture permeability. Almost in all applications, spacer fabrics are compressed by different parts of human body. Body parts have different shapes and curvatures. In all standard methods, spacer fabric compressibility is measured by a pair of flat circular plate which cannot represent a human body. The contour of body can be assumed as cylindrical with varying radius of curvature. So, it is necessary to understand the mechanism of compression of spacer fabric with cylindrical surface in order to understand the performance of the fabric under real-world dynamics. In this research, an effort is being made to predict the compression behaviour of warp-knitted spacer fabric by flat as well as cylindrical surface. Finite Element Models were designed on Abaqus/CAE platform to meet above requirement with variable circumstances. Experimental setup was also made to analyse cylindrical and flat compression at different circumstances. Results show that flat compression and cylindrical compression are largely deferred in terms of shape of load-deformation curve and compressional energy. Effect of variables on compression behaviour was also analysed. Model results were validated with experimental values. It is found that the proposed model has got a good agreement with the experimental results.

scholarly journals Experimental Study on Axial Compression Behavior of Masonry Columns’ Strengthening with Bamboo Scrimber Bar Mesh Mortar Layer

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Hongyao Liu ◽  
Min Lei ◽  
Bowang Chen
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Process ◽  
Engineering Application ◽  
Compression Tests ◽  
Compression Behavior ◽  
Bamboo Scrimber ◽  
Calculation Results ◽  
Strengthening Method

We propose a new method to strengthen structural masonry. To study on the axial compression behavior of masonry columns’ strengthening with a bamboo scrimber bar mesh mortar layer, axial compression tests of twelve masonry columns have been completed: nine strengthened columns and three unstrengthened columns. The failure process, bearing capacity, and failure mode are carried out. The strengthening method of bamboo scrimber bar mesh mortar layer permits the upgrade of the columns’ bearing capacity. The effects of bamboo bar ratio and mortar strengthening ratio on bearing capacity of the reinforced columns are compared. We propose the method for calculating the axial bearing capacity of such a reinforced column. The calculation results agree well with the experimental results, and the research results are available for engineering application.

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