Microscopic Evaluation of Commingling-Hybrid Yarns

2007 ◽  
Vol 539-543 ◽  
pp. 992-996 ◽  
Author(s):  
Bok Choon Kang ◽  
K.H. Min ◽  
Y.H. Lee ◽  
Beong Bok Hwang ◽  
Chathura Nalendra Herath

Fibers made of elements such as carbon, aramid and glass have higher mechanical properties than other conventional textile fibers and they enable the production of light weight composites as end products. Furthermore, commingling hybrid yarns generally have a characteristic feature so that their components are distributed homogeneously enough over the yarn cross section. A normal air texturerising machine was modified to produce commingling hybrid yarns for test samples. Different process parameters were applied to produce the hybridized yarn samples. However, these process parameters turned out to have little effect on the filament distribution over the hybrid yarn cross section in terms of homogeneity. The analysis in this paper is focused on the pattern of mixing of filaments over a cross section of hybrid yarns according to different combinations of reinforcement and matrix filament yarns through microscopic view. The volume content of filament in hybrid yarn cross section was maintained at 50% for both reinforced and matrix, and the hybrid yarns count at 600 tex throughout experiments. It was concluded from the experiments that the diameters of reinforcement and matrix filaments have strong effects on the pattern of mixing of filaments over a cross section of hybrid yarns such that the hybrid yarns with more or less equal diameters of reinforcement and matrix filaments showed considerably even distributions over the hybrid yarn cross section.

2016 ◽  
Vol 869 ◽  
pp. 441-446
Author(s):  
N.L. Vale ◽  
Jorge Fernandez Dos Santos ◽  
I.R. Melo ◽  
Oscar Olimpio Araújo Filho ◽  
Severino Leopoldino Urtiga Filho

Aluminium alloy 7050 in a T7451 temper was friction-stir welded (FSW) to investigate the effects of different process parameters on the microstructure and mechanical properties. Butt joints were obtained in 10mm thick-sheets, keeping a constant rotational speed of 550 rpm. Weld power and torque were recorded for each weld in order to obtain the heat input of the process, since the final properties of the welds are strongly related to this variable. The joints were characterized by optical microscopy and microhardness indentation through the stir zone (SZ), thermo-mechanically affected zone (TMAZ), and heat affected zone (HAZ) at different cross section heights. The processing of FSW, the microstructure in FSW alloys and the factors influencing weld quality are introduced.


2015 ◽  
Vol 813-814 ◽  
pp. 603-607
Author(s):  
T. Pravin ◽  
M. Sadhasivam ◽  
S. Raghuraman

Powder Metallurgy (P/M) is a manufacturing process in which powders are compacted in a die to attain the final product. P/M has certain unique advantage like controlled porosity, High Strength to weight ratio. Aluminium (Al) is a light weight material, but pure Al does not possess a good strength. To achieve the strength, Copper (Cu) powders are blended at required proportions. Al along with Cu shows good mechanical properties. An attempt is made to optimize the process parameter of Al – 10% Cu powder to attain maximum process efficiency. Here optimization is done by Taghuchi’s method.


2006 ◽  
Vol 532-533 ◽  
pp. 337-340
Author(s):  
Chathura Nalendra Herath ◽  
Bok Choon Kang ◽  
Jong Kwang Park ◽  
Yong Hwang Roh ◽  
Beong Bok Hwang

This paper is concerned the breaking elongation properties of Carbon/Aramid-, Carbon/Glass- and Aramid/Glass- matrix hybridized commingling yarns. The hybrid yarns produced by commingling process were investigated in terms of breaking elongation property. In experiments, carbon (CF), aramid (AF), and glass (GF) filament yarns were combined. In this study, selected matrix materials include Polyether-ether-Keeton (PEEK), and polyester (PES), or polypropylene (PP). The volume content of filament in hybrid yarn cross section was maintained at 50% for both reinforced and matrix, ant hybrid yarns count at 600 tex, respectively. The reinforcement to matrix filament combination was selected as 1:1 proportion. The effect of different air pressures and material combinations was investigated in terms of breaking elongation. In experiments, each type of hybrid yarn sample has been tested 20 times at the testing speed of 10mm/min. under 3 bar of yarn clamping pressure. Since breaking elongation is one of most important properties in textile fiber, it was examined closely with reference to the first breaking point of commingling-hybrid yarns. It was concluded from experiments that hybrid yarns with higher breaking elongation and higher tensile strength tend to show better force-elongation relationship. It was also known from experiments that the combination of two reinforcement filament yarns gives always much better results than a single reinforcement filament yarns in terms of elongation property. GF/AF/matrix is shown very much better elongation properties. PP and PES gives higher elongation than PEEK as a matrix material.


2017 ◽  
Vol 742 ◽  
pp. 395-400 ◽  
Author(s):  
Florian Staab ◽  
Frank Balle ◽  
Johannes Born

Multi-material-design offers high potential for weight saving and optimization of engineering structures but inherits challenges as well, especially robust joining methods and long-term properties of hybrid structures. The application of joining techniques like ultrasonic welding allows a very efficient design of multi-material-components to enable further use of material specific advantages and are superior concerning mechanical properties.The Institute of Materials Science and Engineering of the University of Kaiserslautern (WKK) has a long-time experience on ultrasonic welding of dissimilar materials, for example different kinds of CFRP, light metals, steels or even glasses and ceramics. The mechanical properties are mostly optimized by using ideal process parameters, determined through statistical test planning methods.This gained knowledge is now to be transferred to application in aviation industry in cooperation with CTC GmbH and Airbus Operations GmbH. Therefore aircraft-related materials are joined by ultrasonic welding. The applied process parameters are recorded and analyzed in detail to be interlinked with the resulting mechanical properties of the hybrid joints. Aircraft derived multi-material demonstrators will be designed, manufactured and characterized with respect to their monotonic and fatigue properties as well as their resistance to aging.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1157
Author(s):  
Danka Labus Zlatanovic ◽  
Sebastian Balos ◽  
Jean Pierre Bergmann ◽  
Stefan Rasche ◽  
Milan Pecanac ◽  
...  

Friction stir spot welding is an emerging spot-welding technology that offers opportunities for joining a wide range of materials with minimum energy consumption. To increase productivity, the present work addresses production challenges and aims to find solutions for the lap-welding of multiple ultrathin sheets with maximum productivity. Two convex tools with different edge radii were used to weld four ultrathin sheets of AA5754-H111 alloy each with 0.3 mm thickness. To understand the influence of tool geometries and process parameters, coefficient of friction (CoF), microstructure and mechanical properties obtained with the Vickers microhardness test and the small punch test were analysed. A scanning acoustic microscope was used to assess weld quality. It was found that the increase of tool radius from 15 to 22.5 mm reduced the dwell time by a factor of three. Samples welded with a specific tool were seen to have no delamination and improved mechanical properties due to longer stirring time. The rotational speed was found to be the most influential parameter in governing the weld shape, CoF, microstructure, microhardness and weld efficiency. Low rotational speeds caused a 14.4% and 12.8% improvement in joint efficiency compared to high rotational speeds for both tools used in this investigation.


2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.


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