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1.
Delamination is the most common failure mode in laminated composites, due to the reduced strength in the through-the-thickness direction. This paper describes the development of core-and-effect textured glass yarns for improving the bonding strength of laminated glass woven fabric composites. Air-jet texturing introduces bulk and loops in the yarn which provides more contact surface between the fibers and the resin. However, the yarn tenacity decreases after texturing because of the reduced alignment of the filaments. The effects of texturing air pressure, yarn overfeed ratio, yarn linear density and core-sheath ratio were studied in this paper. The tenacity of glass yarns decreased significantly after the texturing process. The reduction was smaller for yarns with a higher core linear density. The effects of texturing air pressure on the tenacity were found to be insignificant. 相似文献
2.
Composite materials have a wide range of applications in structural components because of their high strength-to-weight and stiffness-to-weight ratios. However, the most crucial and common life-restricting crack growth mode in laminated composites i.e. delamination is of great concern. Air jet texturing was selected to provide a small amount of bulk to the glass yarn. The purpose was to provide more surface contact between the fibres and resin and also to increase the adhesion between the neighbouring layers. These were expected to enhance the resistance to delamination in the woven glass composites. The development and characterisation of core-and-effect textured glass yarns was presented in the previous paper. This paper describes the comparison of the mechanical properties of composites produced from air-textured glass yarns and the composites made from locally manufactured carbon fabrics. The tensile, flexure and inter-laminar shear strength (ILSS) were compared and it was observed that although glass fibres are inferior to carbon fibres in terms of mechanical properties however, the flexure strength and ILSS of glass based composites increases after texturing and were found closer to the properties of carbon based composites. 相似文献
3.
The mechanical properties of the nanocomposites are dependent, not only of the clays content but, also, of the resin type and manufacturing process. In this context, the present study intends to develop a systematic study involving a low glass transition temperature (Tg) and low permeability epoxy resin (SR 1500 and the hardener SD 2503) with a commercially Nanomer I30 E nanoclays. Two dispersion processes were compared (direct (DM) and indirect method (IDM)) in terms of mechanical properties, as well as the influence of nanoclay content and hydro aging effect. It was possible to observe that the composites obtained by the indirect method present lower mechanical properties than the neat resin because there is residual acetone. For DM composites the tensile strength, fracture toughness and the specific energy absorbed by impact decreases with the reinforcement content, caused by particle agglomerates. Elastic modulus, at 25 °C, increases significantly and Tg increases slightly with the addition of nanoclays. Hydro aging promotes a progressive decreasing of the tensile strength and fracture toughness, with the clay content, reaching about 15 % and 7 %, respectively, for 6 wt% of nanoclays. On the other hand, a small increasing on specific energy absorbed was observed. 相似文献
4.
In present work, PET FDY has been used to blend with diacetate filaments by air texturing process and core-and-effect air-textured
yarns have been produced. The influences of both over-feeds of core and effect components on properties of textured yarns
were mainly examined. It was observed that a spun-like effect of diacetate filaments occurred during air texturing and there
were a little amount of free fiber ends besides loops on blended air textured yarns, while the number of free fiber ends changed
little with variation in over-feeds. The tenacity of textured yarns decreased with increase in over-feeds of effect or core
component. The breaking elongation increased with increase in over-feed of effect component, but decreased with increase in
over-feed of core component. The yarn stability improves when both over-feeds are increased. The effect of over-feeds on boiling
water shrinkage shows no clear trend. The core and average diameters are higher at high over-feed of effect component, but
the over-feed of core component exhibits little effect on yarn diameters. The number and size of loops are increase with increased
over-feed of effect component. 相似文献
5.
PET yarns textured at different texturing conditions were treated with superheated steam or dry heat at different temperatures
for different times. The effects of the treatment conditions on the thermomechanical and structural changes of the yarn were
examined by shrinkage, X-ray diffraction and birefringence measurements. With increase in superheated steam temperature, the
crystalline orientation factor and birefringence decreased, whereas crystal size increased. Dry heat treatment had a smaller
effect on shrinkage and structural properties in comparison with superheated steam treatment. The additional shrinkage after
texturing process was investigated. The effect of heat-setting in both media was more significant at 200 °C. The time dependence
of the properties was not linear. 相似文献
6.
Influences of processing parameters on tensile property, stability and bulk of core-and-effect air textured yarns of diacetate
and polyester filaments are mainly examined in this paper. When the air pressure is raised, the tenacity and breaking elongation
of textured yarns are reduced, Instability I and II tend to decrease at first and then increase, the core bulk declines markedly
at first and then changes slowly, whereas the overall bulk changes little at first and then goes up greatly. With increase
in texturing speed, the yarn tenacity and breaking elongation both drop initially then begin to increase, the core bulk and
overall bulk are almost linearly increased, while the yarn instability changes with an unclear trend. When the winding underfeed
ratio is increased, the yarn tenacity, breaking elongation and core bulk are reduced, but the yarn stability is slightly improved.
The wetting of the core component produces higher tenacity, breaking elongation, instability and bulk, compared with that
of the effect component or that of both, but the difference is insignificant. 相似文献
7.
This paper presents the results of a current study on polypropylene matrix composites processed by injection, with two different glass fiber lengths and five different volume fractions. Physical and mechanical properties were obtained, namely flexural strength, stiffness modulus and fracture toughness. The mechanical properties of the composites increased significantly with the increase of the fibers volume fraction in agreement with the Counto model. The effect of water immersion time was also analysed. Immersion in water promotes a marked decrease in mechanical properties in the early seven-ten days, and afterwards tends to stabilize. Water causes a decrease of the relative strength which increases with fiber volume fraction and reaches about 29 % and 32 % for 20 % of 4.5 mm fiber length and for 25 % of 12 mm fiber length respectively, after 28 days immersion in water. Fracture toughness increases with fiber volume fraction and is always higher for 12 mm fiber length composites than for 4.5 mm fiber length composites. 相似文献
8.
The present paper is concerned with the effect of cork and rice husk ash micro particles fillers on the mechanical properties
(flexural resistance, fracture toughness, impact absorbed energy, elastic and viscous moduli) of polyester based composite.
Composite sheets were hand molded using weight filler fractions of 1, 2.5, and 5 %. Flexural strength of filled materials
was much lower than the polyester matrix, with more pronounced effect for cork powder, decreasing significantly with filler
content increases. Fracture toughness decreases also on the filled composites. Using cork powder fracture toughness decreases
significantly when filler content increases, while for rice husk ash filler a slight increase was observed. Both fillers improve
absorbed impact energy, peaking at about 2.5 % of filler content. Best improvements were obtained using rice husk ash powder,
reaching about 30 %. Both fillers increase glass transition temperature and the maximum use temperature and also the elastic
modulus compared with polyester. It can be concluded from this study that the used agro-waste materials are attractive reinforcements
from the standpoint of their mechanical properties. 相似文献
9.
Raju Seenivasan Rengasamy Raghavendran Guruprasad Patnaik Asis 《Fibers and Polymers》2005,6(2):146-150
In this paper, friction of air-jet textured yarns is investigated. Using a friction measuring apparatus fabricated in-house,
dynamic friction forces of the yarns under yarn-to-metal (YM) and yarn-to-yarn (YY) rubbing modes are measured. The influence
of processing variables of air-jet texturing viz., overfeed, air pressure, dry/wet texturing and normal/core-and-effect texturing
on dynamic friction is analysed. The results indicate that friction force increases with increasing rubbing speeds and yarn
input tension. YM dynamic friction decreases initially and then starts to increase at higher overfeeds. YY dynamic friction
increases with increasing overfeed. YM dynamic friction decreases with an increase in air pressure while an opposite trend
is observed for YY friction. Wet textured yarns have higher friction than dry textured yarns. Core wetted core-and-effect
textured yarns have higher friction than normal textured yarns. 相似文献
10.
Jun Hee Song 《Fibers and Polymers》2016,17(4):600-607
In this paper, the bending properties of woven carbon/glass and carbon/aramid fabric-reinforced polymer laminates is studied using a combination of experimental analysis and fracture observation. Six types of each hybrid composite were manufactured by lamination of the carbon/aramid fabric and carbon/glass fabric using VARTM. Bending behaviors were fundamentally evaluated for the six types of monolithic composites laminated by the same fabric. The objective was to achieve a good bending strength by effective combination of composite structures using limited amounts of a raw material. It was shown that the bending property was different, depending on the type of fiber, lamination structure, and the number of layers. 相似文献
11.
M. P. Sham Aan M. Krishna H. N. Narasimha Murthy S. K. Rai 《Fibers and Polymers》2010,11(7):1083-1087
The objective of this work was to study the effect of addition of Poly tetramethylene ether glycol (PTMEG) on the mechanical
and flame retardance behaviour of novolac phenolic/carbon fiber composites (NPCC). The miscibility of PTMEG and novolac phenolic
resin was studied using DSC. Both modified and unmodified novolac phenolic resins were characterised for chemical structure
using FTIR. The 8 wt% PTMEG/NPCC yielded 39 % increase in impact strength compared to that of unmodified NPCC. Void content
of the composites were measured. Both NPCC and PTMEG blended NPCC were tested for tensile strength (UTS), flexural strength
(FS), inter laminar shear strength (ILSS) and impact strength. Also morphological studies were carried out using SEM. The
UTS, FS, ILSS and impact strength of the modified NPCC showed better results at 8 wt% of PTMEG without any compromise on the
flame retardancy. The fracture surface examination showed good adhesion between the fiber and the matrix in the modified NPCC. 相似文献
12.
Normasmira A. Rahman Aziz Hassan R. Yahya R. A. Lafia-Araga 《Fibers and Polymers》2013,14(11):1877-1885
Glass fiber reinforced polypropylene composites were compounded with a twin-screw extruder and injection molded. Fiber length distribution study showed that more fiber degradation occurred during processing of the composites with higher fiber loading. Dynamic mechanical analysis carried out showed that magnitudes of storage and loss modulus of composites are improves with the presence of the glass fiber in the system. The incorporation of fibers into the composites has slightly shifted the glass transition temperature to lower values. On the other hand, the presence of the glass fiber reduces the magnitude of tan δ at α-transition dramatically due to the strengthening effect by the fibers. From impact test, it was found that increment in glass fiber loading leads to an increase in peak load, critical strain energy release rate and critical stress intensity factor indicating the improvement in the material toughness. However, there was no significant change observed in fracture energy. With respect to increasing in specimen geometry, despite an improvement in peak load and fracture energy of the impact specimen, the critical strain energy release rate and critical stress intensity factor values were decreased. On the other hand, increase in test temperature resulted in reduction of peak load and critical stress intensity factor due to increment in material ductility, whereby fracture energy and critical strain energy release rate improved. 相似文献
13.
Based on the situ preparation of silica nanoparticles (SiO2) on the surface of Graphene nanoplatelets (GNPs) in the previous work, these unique three dimensional (3D) materials were introduced into epoxy resin to study the reinforcing and toughening synergy effect on the composites. Firstly, the tensile tests showed that Graphene/SiO2 hybrid materials attached with different size of SiO2 particles exhibited different reinforcing and toughening effect on the composites. With the increasing of the diameter of SiO2 particles, the toughness and strength properties of the composites firstly improved and then decreased, and when the average diameter was 0.14 μm, the elongation reached the max.. Meanwhile, the fractured surfaces presented on SEM images were consistent with the results of the tensile tests, which further explained the hybrid materials increased the interfacial adhesion between the fillers and matrix, leading to significant improvement in mechanical properties. Moreover, the DSC curves demonstrated that Graphene/SiO2 hybrid materials accelerated the curing process of epoxy resin due to the cross-link structure between fillers and matrix. Lastly, the crack propagation modes were built to clarify the synergy effect mechanism of reinforcing and toughening on nanoparticles/epoxy resin composites. 相似文献
14.
In this study, spinning with a contact surface was introduced as a simple and energy-saving method to reduce spun yarn hairiness. Theoretical analysis indicated that yarn hairiness could be reduced via a sufficient long contact surface applied in other part of yarn formation zone in addition to spinning triangle. Then, a simple contact apparatus was installed on ring frame to validate the theoretical analysis. Results proved that yarn hairiness was reduced via a contact surface in the yarn formation zone. However, unevenness was deteriorated for most yarns spun with contact apparatus during the spinning, which might be due to fiber mass concentration. Most of yarns spun with contact apparatus had a lower strength than the conventional yarns. This might be because evenness deterioration to decrease yarn strength overpowered hairiness reduction to increase yarn strength for most yarns spun with a contact surface. 相似文献
15.
This study has examined the flexural properties of natural and chemically modified coir fiber reinforced cementitious composites
(CFRCC). Coir fibers of two different average lengths were used, and the longer coir fibers were also treated with a 1 % NaOH
solution for comparison. The fibers were combined with cementitious materials and chemical agents (dispersant, defoamer or
wetting agent) to form CFRCC. The flexural properties of the composites, including elastic stress, flexural strength, toughness
and toughness index, were measured. The effects of fiber treatments, addition of chemical agents and accelerated ageing of
composites on the composites’ flexural properties were examined. The results showed that the CFRCC samples were 5–12 % lighter
than the conventional mortar, and that the addition of coir fibers improved the flexural strength of the CFRCC materials.
Toughness and toughness index, which were associated with the work of fracture, were increased more than ten times. For the
alkalized long coir fiber composites, a higher immediate and long-term toughness index was achieved. SEM microstructure images
revealed improved physicochemical bonding in the treated CFRCC. 相似文献
16.
The properties of a woven fabric made of poly(trimethylene terephthalate) (PTT) were investigated. The PTT fabric of draw
textured yarn (DTY) showed excellent stretch as good as a fabric containing spandex. However, the unique stretch of the PTT
fabric reduced dramatically by simple heat-treatment even at as low as 80 °C. To understand the phenomenon, the crimp rigidity
of the DTY was observed by SEM. It was found that the drastic reduction of stretch was caused by irreversible uncrimping of
PTT DTY after heat-treatment. Conclusively, it is of importance to optimize the texturing conditions for PTT DTY to make the
crimp more stable. 相似文献
17.
The present study explored the preparation of glass fiber-coir reinforced unsaturated polyester resin hybrid (GCU) composites with a novel Prepreg/Press fabrication process. Flexural, impact and thermal-mechanical properties of GCU composites were investigated. Coir reinforced unsaturated polyester resin (CU) composites was also prepared with the same process to explore the enhancement effect of glass fabric on the mechanical properties of coir-based composites. The effect of fabrication pressure on the mechanical properties of CU and GCU composites was examined. Micromorphology and interfacial reaction of the composites were analyzed. It is shown that GCU composites fabricated with the Prepreg/Press process have excellent flexural strength (185.0 MPa), MOE (18.3 GPa), and impact strength (67.2 kJ/m2). The mechanical properties of GCU composites increased with the increase of applied pressure up to 0.8 MPa in the Prepreg/Press process. However, further increase of applied pressure led to the decrease in mechanical properties. The addition of glass fabrics to GCU composites showed 419 % improvement in flexural strength, 708 % improvement in MOE and 562 % improvement in impact strength over coir-based composites. The micromorphology study proved that the poor interfacial bonding between coir and matrix led to the low mechanical properties of coir-based composites. 相似文献
18.
I. D. G. Ary Subagia Zhe Jiang Leonard D. Tijing Yonjig Kim Cheol Sang Kim Jae Kyoo Lim Jae Kyoo Lim 《Fibers and Polymers》2014,15(6):1295-1302
In this study, we report the fabrication and evaluation of a hybrid multi-scale basalt fiber/epoxy composite laminate reinforced with layers of electrospun carbon nanotube/polyurethane (CNT/PU) nanofibers. Electrospun polyurethane mats containing 1, 3 and 5 wt% carbon nanotubes (CNTs) were interleaved between layers of basalt fibers laminated with epoxy through vacuum-assisted resin transfer molding (VARTM) process. The strength and stiffness of composites for each configuration were tested by tensile and flexural tests, and SEM analysis was conducted to observe the morphology of the composites. The results showed increase in tensile strength (4–13 %) and tensile modulus (6–20 %), and also increase in flexural strength (6.5–17.3 %) and stiffness of the hybrid composites with the increase of CNT content in PU nanofibers. The use of surfactant to disperse CNTs in the electrospun PU reinforcement resulted to the highest increase in both tensile and flexural properties, which is attributed to the homogeneous dispersion of CNTs in the PU nanofibers and the high surface area of the nanofibers themselves. Here, the use of multi-scale reinforcement fillers with good and homogeneous dispersion for epoxy-based laminates showed increased mechanical performance of the hybrid composite laminates. 相似文献
19.
This study examined the effects of the total porosity, pore size, and cover factor on the moisture and thermal permeability of woven fabrics made from DTY (draw textured yarns) and ATY (air jet textured yarns) composite yarns with hollow PET (polyethylene terephthalate) yarns. The wicking of the hollow composite yarn fabrics was found to be superior to that of the high twisted yarn fabrics, which may be due to the high porosity in the hollow composites yarns, but this was not related to the cover factor. The drying characteristics of the hollow composite yarn fabric with high porosity were inferior compared to the high twisted yarn fabrics due to the large amounts of liquid water in the large pores, which resulted in a longer drying time of the fabric. The thermal conductivity of the hollow composite yarn fabrics decreased with increasing measured pore diameter due to the bulky yarn structure. The effects of the hollowness of the yarn on the thermal conductivity were more dominant than those of the yarn structural parameters. The air permeability increased with increasing measured pore diameter but the effects of the cover factor on the air permeability were not observed in the hollow composite yarn fabrics. The effects of porosity on the moisture and thermal permeability of the woven fabrics made from the hollow composite filaments were found to be critical, i.e., wicking and air permeability increase with increasing porosity. In addition, the drying rate increased with increasing porosity and the thermal conductivity decreased with increasing pore diameter, but were independent of the cover factor. 相似文献
20.
Fully biodegradable and environment-friendly green composite specimens were made using ramie fibers and soy protein concentrate
(SPC) resin. SPC was used as continuous phase resin in green composites. The SPC resin was plasticized with glycerin. Precuring
and curing processes for the resin were optimized to obtain required mechanical properties. Unidirectional green composites
were prepared by combining 65 % (on weight basis) ramie fibers and SPC resin. The tensile strength and Young’s modulus of
these composites were significantly higher compared to those of pure SPC resin. Tensile and flexural properties of the composite
in the longitudinal direction were moderate and found to be significantly higher than those of three common wood varieties.
In the transverse direction, however, their properties were comparable with those of wood specimens. Scanning electron microscope
(SEM) micrographs of the tensile fracture surfaces of the green composite indicated good interfacial bonding between ramie
fibers and SPC resin. Theoretical values for tensile strength and Young’s modulus, calculated using simple rule of mixture
were higher than the experimentally obtained values. The main reasons for this discrepancy are loss of fiber alignment, voids
and fiber compression due to resin shrinking during curing. 相似文献