scholarly journals Yarn Damage Evaluation in the Flat Knitting Process

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Waqar Iqbal ◽  
Yaming Jiang ◽  
Ye-xiong Qi ◽  
Lei Xu
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Raw Materials ◽  
Frictional Coefficient ◽  
Microscopic Analysis ◽  
Significant Loss ◽  
Cross Sectional ◽  
Knitted Fabrics ◽  
Technical Textiles ◽  
Yarn Properties

AbstractTextile yarns are subjected to numerous types of forces during knitting, usually leading to yarn damages, such as decrease in tensile, bending, shearing, and surface properties, which are closely related to different yarn properties, knitted structures/actions, and machine settings. This article comprehensively evaluated yarn damages in the computerized flat knitting process. Five different commercially available and commonly used yarns including cotton, wool, polyester, acrylic, and viscose were selected as raw materials, and the tensile, bending, shear, and frictional properties were investigated and compared before knitting and after being unraveled from plain- and rib-knitted fabrics, respectively. The results show that knitting actions/structures exhibit different damage extents for all different raw materials. It has been observed that the modulus is declined by 3–30% for bending, 2–10% for tensile, and 8–80% for shearing due to flat knitting action, respectively. The frictional coefficient of yarns also increased from 6 to 23%. As compared to yarn before knitting, the yarns unroved from plain and rib structures have been damaged to a great extent as a result of the loss of mechanical properties. The results are completely in agreement with the statistical analysis that clearly represents the significant loss in yarn properties during the knitting process. The microscopic analysis of the yarns clearly illustrates the effect of knitting action on yarn surface and mechanical properties. For yarn’s cross-sectional shearing properties testing, this article self-designed an innovative “Yarn Shear Testing Device.” The methodology and results are of great importance for improving the quality of knitted products, evaluating knitting yarns’ knittability, and in the development of high-performance technical textiles.

scholarly journals Comparative Study of High-Performance Concrete Characteristics and Loading Test of Pretensioned Experimental Beams

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 427
Author(s):  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Load Capacity ◽  
Materials Testing ◽  
Loading Test ◽  
Conventional Concrete ◽  
Concrete Mechanical Properties ◽  
Normal Strength

High-performance concrete (HPC) is subjected to wide attention in current research. Many research tasks are focused on laboratory testing of concrete mechanical properties with specific raw materials, where a mixture is prepared in a relatively small amount in ideal conditions. The wider utilization of HPC is connected, among other things, with its utilization in the construction industry. The paper presents two variants of HPC which were developed by modification of ordinary concrete used by a precast company for pretensioned bridge beams. The presented variants were produced in industrial conditions using common raw materials. Testing and comparison of basic mechanical properties are complemented with specialized tests of the resistance to chloride penetration. Tentative expenses for normal strength concrete (NSC) and HPC are compared. The research program was accomplished with a loading test of model experimental pretensioned beams with a length of 7 m made of ordinarily used concrete and one variant of HPC. The aim of the loading test was to determine the load–deformation diagrams and verify the design code load capacity calculation method. Overall, the article summarizes the possible benefits of using HPC compared to conventional concrete.

Microscopic Analysis and Study of High-Performance Seawater All-Coral Concrete

2019 ◽  
Vol 815 ◽  
pp. 216-222
Author(s):  
Chao Chen ◽  
Jin Ming Liu ◽  
Yang Yang ◽  
Zhi Guo Guo
Keyword(s):  
Mechanical Properties ◽  
Natural Environment ◽  
High Performance ◽  
Work Performance ◽  
Room Temperature ◽  
Microscopic Analysis ◽  
Internal Curing ◽  
Mix Design ◽  
Binder Ratio ◽  
Water To Binder Ratio

The ocean islands are far from inland and the concrete sandstone aggregates are scarce. In this paper, high-performance seawater all-coral concrete was developed by seawater mixing and room temperature maintenance design, and by optimizing the water-to-binder ratio, regulating internal curing, changing auxiliary cementing materials and blending ratio, incorporating expansion agent, adjusting fiber blending, etc. Combined with the consideration of work performance and mechanical properties, the concrete self-shrinkage is adjusted to further optimize the mix design. The mechanical properties of the optimized high-performance seawater all-coral concrete were studied, and the relevant durability tests were carried out according to the natural environment characteristics of the island. This is of great significance to the construction of island projects, repair and construction, and construction of protective projects [1].

A review on the mechanical properties of textile structural composite T-beams

2019 ◽  
Vol 90 (5-6) ◽  
pp. 710-727 ◽  
Author(s):  
Yiwei Ouyang ◽  
Xianyan Wu
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Raw Materials ◽  
Research Progress ◽  
Future Research ◽  
Research Directions ◽  
Structural Composite ◽  
Delamination Resistance ◽  
Application Potential ◽  
Future Research Directions

In order to review the most effective ways to improve the mechanical properties of composite T-beams and further increase their application potential, research progress on the mechanical properties of textile structural composite T-beams was summarized based on two-dimensional (2-D) ply structure composite T-beams, delamination resistance enhanced 2-D ply structure T-beams, and three-dimensional (3-D) textile structural composite T-beams; future research directions for composite T-beams were also considered. From existing literature, the research status and application bottlenecks of 2-D ply structure composite T-beams and T-beams with enhanced delamination resistance performance were described, as were the specific classification, research progress, and mechanical properties of 3-D textile structural composite T-beams. In addition, the superior mechanical properties of 3-D braided textile structural composite T-beams, specifically their application potential based on excellent delamination resistance capacity, were highlighted. Future research directions for composite T-beams, that is, the applications of high-performance raw materials, locally enhanced design, structural blending enhancement, functionality, and intelligence are presented in this review.

scholarly journals The Effect of Number and Position of Tuck Stitches within the Pattern Repeat on Air Permeability of Weft-knitted Fabrics from Glass Yarn

2019 ◽  
Vol 2 (3) ◽  
pp. 317-323
Author(s):  
Mehmet Erdem İnce
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Air Permeability ◽  
Knitted Fabric ◽  
Knitted Fabrics ◽  
Synthetic Fibers ◽  
Fabric Structure ◽  
Knit Fabrics ◽  
Weft Knitted Fabric

The fact that weft knitted fabrics has a stretchable, 3D, porous and interlocking structure makes them unique when manufactured from high performance fibers. Knitted fabrics with different architectures exhibit different properties. Different loop forms like tuck and skip stitches with various loop lengths reveal different physical and mechanical properties. Literature review indicated that wisely arrangement of tuck stitches within the pattern repeat alter the weft-knitted fabric structure from natural and synthetic fibers. Therefore, we studied the effect of number and location of tuck stiches on air permeability of weft-knitted fabrics from glass yarn. Single-bed, flat weft knitting machine was used to knit fabrics with different architectures from three-ply glass yarn. The nominal single-end count of used E-glass yarn was 136 tex. It is anticipated that the number and location of tuck stitches within knit pattern effect physical and air permeability properties of weft-knitted fabrics from glass yarn.

scholarly journals Microstructural Features and Mechanical Properties after Industrial Scale ECAP of an Al 6060 Alloy

2010 ◽  
Vol 667-669 ◽  
pp. 1153-1158 ◽  
Author(s):  
Philipp Frint ◽  
Matthias Hockauf ◽  
T. Halle ◽  
G. Strehl ◽  
Thomas Lampke ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Zone ◽  
High Performance ◽  
Large Scale ◽  
Low Voltage ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Industrial Scale ◽  
Opening Angle ◽  
Cross Sectional

Future applications of ultrafine-grained, high performance materials produced by equal-channel angular pressing (ECAP) will most likely require processing on an industrial scale. There is a need for detailed microstructural and mechanical characterisation of large-scale, ECAP-processed billets. In the present study, we examine the microstructure and mechanical properties as a function of location and orientation within large (50 x 50 x 300 mm³) billets of an Al 6060 alloy produced by ECAP (90° channel angle) with different magnitudes of backpressure. The internal deformation is analysed using a grid-line method on split billets. Hardness is recorded in longitudinal and cross-sectional planes. In order to further characterise the local, post-ECAP mechanical properties, tensile tests in different layers are performed. Moreover, low voltage scanning transmission electron microscopy observations highlight relevant microstructural features. We find that the homogeneity and anisotropy of mechanical properties within the billets depend significantly on the geometry of the shear zone. We demonstrate that deformation gradients can be reduced considerably by increasing the backpressure: The opening-angle of the fan-shaped shear zone is reduced from ψ ≈ 20 ° to ψ ≈ 7 ° when the backpressure is increased from 0 to 150 MPa. Backpressures of 150 MPa result in excellent homogeneity, with a relative variation of tensile mechanical properties of less than 7 %. Our investigation demonstrates that ECAP is suitable for processing homogenous, high performance materials on a large scale, paving the way for advanced industrial applications.

Adhesive Systems for the Production of Multi-Layer Bonded Fabrics for Composite Applications

2014 ◽  
Vol 936 ◽  
pp. 1816-1820 ◽  
Author(s):  
Iris Käppler ◽  
Ayham Younes ◽  
Georg Bardl ◽  
Chokri Cherif
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Adhesive Bonding ◽  
Adhesive Systems ◽  
Adhesion Properties ◽  
Reinforced Plastics ◽  
Novel Technology ◽  
Technical Textiles ◽  
Set Up ◽  
Manufacturing Technologies

Nowadays Non-Crimp Fabrics (NCF) are of substantial use in the field of technical textiles. Due to their lightweight, multilayer set-up, NCF became to an important factor for several technology sectors, i. e. automotive, wind energy and civil engineering. In order to eliminate known drawbacks of current manufacturing technologies, to enhance mechanical properties and to increase production speed of such NCF, a novel technology is proposed. This manufacturing technique is based on the adhesive bonding of layers made of high-performance fibres. Different adhesives were investigated to check their wettability and adhesion properties in relation to the high-performance fibres made of carbon or glass. Furthermore, the interface between the adhesive and a classical matrix for fibre-reinforced plastics was examined.

scholarly journals THE EFFECT OF FIBER CROSS-SECTIONAL SHAPE AND TEXTURING TEMPERATURE ON KNITTED FABRIC AIR PERMEABILITY

2019 ◽  
Vol 2019 ◽  
pp. 100-104
Author(s):  
Halil İbrahim ÇELİK ◽  
Hatice Kübra KAYNAK ◽  
Esin SARIOĞLU ◽  
Gizem KARAKAN GÜNAYDIN
Keyword(s):  
Raw Materials ◽  
Air Permeability ◽  
Process Temperature ◽  
Knitted Fabric ◽  
Cross Sectional ◽  
Knitted Fabrics ◽  
Polyester Filament ◽  
Process Factors ◽  
Sectional Shape ◽  
Single Jersey

Texturized yarns are often preferred especially in home textiles and sportswear. To improve polyester filament properties, mechanical, thermal, chemical and combinations of texturing processes are applied. With these processes, filament yarns take on a curved and voluminous structure and gain a permanent form. Properties of the texturized yarn can be varied as raw materials properties, machine type and process factors. This study covers the investigation of the effect of cross-sectional shape of fiber (round and trilobal) and texturing process temperature (150, 175 and 200 0C) on air permeability of false twist textured polyester single jersey knitted fabrics. Results showed that the highest air permeability value was obtained from knitted fabric with round fiber cross-sectional shape polyester filament textured at 150 0C. According to the statistical analysis, both the fiber cross-sectional shape and process temperature were found to have a significant effect on air permeability property.

Physical properties of lyocell-reinforced polypropylene composites from intermingled fibre with varying fibre volume fractions

2017 ◽  
Vol 31 (8) ◽  
pp. 1029-1041 ◽  
Author(s):  
Michael Cordin ◽  
Thomas Bechtold
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance ◽  
Raw Materials ◽  
Moisture Sorption ◽  
Cellulose Fibre ◽  
Fibre Volume ◽  
Textile Fibre ◽  
Cellulose Fibres ◽  
Cellulose Composites

Polypropylene (PP)-cellulose fibre blends exhibit substantial potential for the production of high-performance textile fibre–reinforced composites. The production of reinforced parts from PP-cellulose composites through thermal shaping of intermingled fibre blends is a strategy to form parts which exhibit superior mechanical properties. In this study, the use of intermingled fibre slivers with different ratios of lyocell fibres (CLY) and PP fibres as raw materials for thermally formed composites was investigated. Such a concept will maximize the interface between the reinforcement fibres and polymer matrix. The cellulose fibres remain oriented along the direction in which the drawing process was performed, which forms the basis for tailored fibre placement in technical production. Because of good surface contact between the cellulose fibre surface and PP matrix, no special coupling agents were required to improve the interfacial adhesion between the two different polymers. The share of CLY and PP fibres in the composite varied from 50% w/w CLY content, up to 70% w/w CLY. Besides analysis of the mechanical properties, such as tensile strength and E-modulus, attention was directed towards moisture sorption of the composites. The rate of sorption and amount of water bound in the composite were found to be dependent on the cellulose fibre content. Composites with a higher CLY content exhibited a more rapid and higher moisture uptake. In water saturated state, the ultimate tensile strength of composites reduced from 160 MPa to 90 MPa, which is an indicator for a reduced adhesion between the CLY surface and PP matrix. The results indicate the potential of the intermingled fibre concept blend for the efficient manufacturing of composite parts.

A Study on Toughening and Strengthening of Mg-Al Spinel Transparent Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1207-1210 ◽  
Author(s):  
Cun Bing Huang ◽  
Tie Cheng Lu ◽  
Li Bin Lin ◽  
Mu Yun Lei ◽  
Cun Xin Huang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Performance ◽  
Radial Crack ◽  
Raw Materials ◽  
Hot Isostatic Pressing ◽  
Molar Ratio ◽  
Transparent Ceramics ◽  
Vacuum Sintering ◽  
Two Stage

Transparent Mg-Al spinel ceramics of four different nonstoichiometries were obtained utilizing two-stage sintering technique of vacuum sintering and post hot isostatic pressing using MgO·nAl2O3 powders with n of 1, 1.3, 1.5 and 1.8, respectively, as raw materials. The mechanical properties of the ceramics were measured and indentation shapes and radial crack propagations were observed. The results showed that change of molar ratio of Al2O3 to MgO leads to variation of indentation shapes and crack propagations of the ceramics, resulting in the change of mechanical properties of the ceramics. The flexural strengths of the ceramics increase first then decrease with increasing n. However, the hardness and fracture toughness of the ceramics increase with increasing n. As a result, an optimal n for high performance ceramic is suggested to be 1.5. In addition, mechanisms of toughening and strengthening of the transparent ceramics have also been discussed.

Microstructural and Mechanical Properties of Autoclaved Saline Soil Brick: Part I: Microstructure Features

2012 ◽  
Vol 510 ◽  
pp. 650-654 ◽  
Author(s):  
Lie Qu ◽  
Lei Guo ◽  
Jiu Jun Yang ◽  
Shou Xi Chai ◽  
Su Li
Keyword(s):  
Mechanical Properties ◽  
Saline Soil ◽  
Raw Materials ◽  
Microscopic Analysis ◽  
Quartz Surface ◽  
Hydration Products ◽  
Hydrothermal Reactions ◽  
Changing Trend ◽  
Diffraction Peaks ◽  
Materials Used

Effects of different components, autoclaving temperature and autoclaving time on the microstructure features and mechanisms of hydrothermal reactions of activated saline soil were investigated by using XRD, DAT and other microstructural analytical methods. Collected from Tianjin Binhai New District, the mainly raw materials used in this study are the saline soil ( 65%) supplemented with calcareous materials. The results demonstrate that with an increasing calcium to silicon ratio, the diffraction peaks of C2SH(A) and tobermorite fluctuate; the peaks increase initially, then dip down slightly before rising up again. With increasing autoclaving time, the order of generated hydration products is as following: C2SH(A) tobermorite gyrolite. Specifically, once autoclaving time reaches 3h, the changing trend of C2SH(A) to tobermorite becomes obvious, and the conversion from tobermorite to gyrolite can also be observed easily. The hydration products of autoclaved saline soil include mainly C2SH(A) and tobermorite, along with a small amount of CSH(B). Microscopic analysis observed by us reveals that a number of scattered, small and white tobermorite crystals are closely attached to quartz surface, which might play a key role in increasing the strength of the system.

Sign in / Sign up

Export Citation Format

Share Document