Composite Tapes Research Articles

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Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2016, 94 (10), p 17March 7, 2016Cite this:C&EN 94, 10, 17AbstractWeil Group Resources is building a facility in Saskatchewan to annually refine 1.1 million m3 of helium from local gas wells. Linde is providing technology and will also buy and market the output of the plant, which is scheduled to open late this year. Air Liquide has inaugurated its second research facility in China. Built in Shanghai’s Minhang district, the lab can support 250 researchers working on energy transition, emissions reduction, wastewater treatment, food safety, health care, and other customer problems. Saudi Basic Industries Corp. has acquired a majority stake in Fibre Reinforced Thermoplastics of Lelystad, the Netherlands. The company makes engineering thermoplastic composite tapes used in transportation and construction. Mitsui Chemicals, Jayant Agro-Organics, and partners have inaugurated a facility in Gujarat, India, that can make 8,000 metric tons per year of biobased polyol, a polyurethane raw material. Fed by locally sourced castor oil, the plant is “overwhelmingly cost-competitive,” MitsuiView: PDF | Full Text HTML

Composite Textured Substrate Tape for Second-Generation High-Temperature Superconductors with Low Magnetic Susceptibility

A design has been developed for three-layer composite substrate tapes based on a nickel-tungsten alloy and corrosion-resistant steel. Materials have been picked and experimental samples of three-layer composite tapes obtained. It has been shown that the substitution of corrosion-resistant steel for ferromagnetic nickel–tungsten alloy in 60% of the tape volume decreases the saturation magnetization of the substrate tape by a factor of 2. The mechanical properties of the composite three-layer tape have been investigated. It has been shown that composite tapes are close in terms of the mechanical properties to tapes made from a homogeneous nickel–tungsten alloy. The conditions for the formation of a sharp cubic texture have been determined.

Investigation of sub-melt temperature bonding of carbon-fibre/PEEK in an automated laser tape placement process

Automated placement of thermoplastic-based composite tape is a highly non-isothermal process with temperature gradients often exceeding 1000°C/s. Models for the process often assume that bonding ceases below the melting point, however the extreme cooling rates combined with high placement velocities can result in a highly amorphous polymer during consolidation. Bonding below the melting point is generally limited due to the presence of crystallites which impede reptation of the polymer molecules, however in the case of an amorphous state, autohesion should proceed. This paper investigates bonding of carbon-fibre(CF)/PEEK with experimental trials performed where sub-melting point temperatures occur at the nip point. The thermal history was recorded with thermocouples embedded in the substrate. Bond predictions are compared with experimental strengths determined by lap shear measurements. Bonding below the melting point was shown to occur, indicating the processing window could be wider than previously estimated by bonding models, particularly for higher placement rates.

Mechanical Behaviours in Bi2223/Ag/Ag Alloy Composite Tape with Different Volume Fractions

Bi2Cr2Ca2Cu3O x (Bi2223) composite tapes consisting of Bi2223 filaments, metal Ag and Ag alloy are usually exposed to a high magnetic field. The mechanical behaviour of composites is determined by the distribution and content of Bi2223 filaments in a magnetic field. Several Bi2223 composite tapes have different volume fractions of Bi2223 filaments, and the volume fraction is of fundamental importance in the determination of mechanical behaviour. In this paper, we present mechanical response to understand the effect of volume fraction of Bi2223 filaments. The critical current density is determined with consideration of the self field effect firstly. Then, the results of effective elastic moduli and mechanical stresses are presented based on the micromechanics approach. The mechanical response depends not only on the material properties but also on the Lorentz force. It is concluded from the computational results that the reduction of volume fraction of filaments can increase the mechanical stability, while the critical current density is decreased. Thus, it is necessary to consider both the mechanical limitation and requirement of the critical current of tape.

Математическая модель лентопротяжного тракта станка для намотки изделий из композиционных материалов

At present products manufactured by winding, are widely used in many industries. The use of modern management tools winding process required the development of adequate mathematical description of this process. Known mathematical model derived previously do not take into account features of behavior of "wet" composite tape as it passes through non-rotating guide path of the winding. The mathematical model takes into account the specific features of "wet" winding, allows a comprehensive study of the system of tension control, structural-parametric synthesis of control systems, perform analysis of static, dynamic and energy performance of the system.

Research on Fuzzy Control Based Flexible Composite Winding System

In the process of composite resin prepreg tape winding, the presence of pores or voids among the layers of composite can result in reduced strength of winding. To alleviate this problem, it is required that the composite tape winding machines be designed such that the layers of composite are evenly wound on the previous one. The paper presents a novel design of flexible winding system for composite tape winding. Based on the analysis of errors in winding process, the novel winding system eliminates winding point error and winding angle error based on the speed controlled flexible roller. This paper also presents the kinetic analysis of the novel system and its controller design. Experiments are conducted on the novel winding system. The experimental results illustrate that the novel flexible winding system has a good performance in winding accuracy.

Strengthening Timber Roof Trusses During Building Construction and Reconstruction

The relevance of this article is explained by the increasingly extensive efforts associated with construction and reconstruction of buildings and structures having mainly architectural and cultural significance, as well as preserving their pristine ambience and integrity for use by future generations. Furthermore, reconstruction helps to serve a range of social demands, such as the provision of comfortable and safe living conditions for people. The review of research publications shows that wooden structures are the first to lose their load-bearing capacity during the long-term use of buildings and structures. Still, the scientific literature mostly features the traditional labor-intensive methods of timberwork strengthening that further increase its weight, or the methods of external reinforcing with composite tapes. This article, for the first time, discusses the technology of the strengthening timber framing with butterfly-shaped wooden inserts. Joints between existing rafters and wooden inserts are reinforced with two layers of the furniture duct tape and fine composite mesh pressed in between, with the plywood top finishing of the duct tape. The experimental studies that were in progress for two years showed that the technology suggested meeting all the reliability requirements applicable for timber trusses. As compared to traditional technologies, the suggested solution is less labor-intensive and more sparing in terms of the truss weight, as it only adds the weight of furniture duct tape, composite mesh and plywood at the joints. This is the applied research, and its outcome can be used not only for strengthening of roof timber, but also for reinforcing of wooden inter-floor joists.

Relation of Critical Current and <i>n</i>-Value of Local Sections to Those of Sample in a Multi-Filamentary Bi2223 Superconducting Composite Tape with Applied Stress-Induced Cracks

Relation of Critical Current and <i>n</i>-Value of Local Sections to Those of Sample in a Multi-Filamentary Bi2223 Superconducting Composite Tape with Applied Stress-Induced Cracks

Continuous micro-/nano-fiber composites of polyamide 6/polyethylene oxide with tunable mechanical properties using a novel co-extrusion technique

Continuous fibrous composite tapes of polyamide 6 (PA6)/polyethylene oxide (PEO) containing over 16 thousand individual ribbon-like PA6 micro-/nano-fiber domains were produced using a novel co-extrusion and two-dimensional multiplication technique. This melt-based process is suitable for scaling-up, applicable to any melt-processable polymers, and highly adjustable in terms of material composition, tape geometry, and number/size of the fiber domains. The PA6 fibrous tapes were post-oriented to achieve superior mechanical properties that are comparable with commercial strong polymeric fibrous composite tapes. The high tunability of tape and fiber structure and properties makes the co-extruded PA6/PEO tapes a desirable candidate for various strong tape applications.

Influence of the Movement of the Neutral Axis on the Relation Between the Critical Current and Strain in Bending Bi2223/Ag Composite Tapes

For the Bi2223/Ag composite tape, on the existence of thermally residual stress, the neutral axis usually shifts away from the center of the cross section due to the Bauschinger effect of Ag and Ag alloy under the bending deformation. The movement of the neutral axis causes the redistribution of the stress and strain in the tape and further affects its critical current. In this paper, based on our modified model with the damage stress of the Bi2223 superconducting filaments, the movement of the neutral axis, the influence of the movement on the relation of the critical current versus the bending strain, and the distribution of the stress and strain on the cross section have been studied. The calculated results show that, the relation of the normalized critical current I c/I c0 versus the bending strain with taking account of the movement of the neutral axis is closer to the experimental data than without that, the neutral axis moves always to the compressive side of the tape, and the movement increases with the bending radius R decreasing (i.e., the bending deformation increasing). Furthermore, in the different cases of the Bauschinger effect factor (BEF), the elastic modulus and volume fraction of the superconducting filaments, the movement of the neutral axis, the normalized critical current I c/I c0 with the bending radius R, and the distributions of the stress on the cross section have been comprehensively investigated.

Influence of deformation and annealing conditions on the recrystallization cube texture in the three-layer NiW/NiCr/NiW substrate tapes

The formation of a sharp cube texture in a three-layer composite tape with the outer (working) layers made of an Ni–4.8 at % W alloy and the inner layer made of an Ni–11 at % Cr alloy is studied after cold deformation by rolling at a reduction of 98.4–99.5% and subsequent recrystallization annealing at a temperature of 1000–1150°C. An analysis of the sharpness of the cube texture and the magnetic properties of the three-layer composite material shows that such tapes can be used as substrates to create second-generation HTSC. At a temperature of 80 K, the specific magnetization of the composite three-layer tape is lower than that of a widely used tape made of an Ni–5 at % W alloy.

Processing-structure–property relationships of novel fibrous filters produced by a melt-process

Fibrous filters were produced using a novel melt-based co-extrusion and two-dimensional multiplication technology combined with a delamination technique using high-pressure water jets. The fibrous filters produced comprising continuous and rectangular polypropylene (PP)/polyamide 6 (PA6) micro/nano-fibers have structural integrity and uniform fiber distribution. The orientation procedure greatly improves the PP/PA6 crystal orientation, decreases the fiber sizes, and enhances their mechanical performance as filters. These filters have large surface area, micron-sized pores, and high porosity (~90 %), which are desirable for microfiltration applications. Structural and property analysis was performed on the PP/PA6 fibrous filters produced from varying number of plies of the composite tapes with different draw ratios and fiber width-to-thickness ratios. It was found that increasing the tape draw ratio improves the surface area and porosity of the filters, and decreases its pore size. Using more plies generates decreased filter pore size and unaffected porosity. Filters comprising fibers with higher width-to-thickness ratio have higher surface area, smaller pore size, and unchanged porosity. This melt-based, versatile technology is applicable to any melt-processable polymers to produce fibrous filters having tunable properties for various filtration applications.

Development of a Novel Ablative Composite Tape Layup Technology for Solid Rocket Motor Nozzle and Liquid Engine Liners

Solid rocket motor nozzles and liquid engine throats use ablative composite materials to protect the structures from the extremely severe operating conditions of high temperature, pressure and particle impingement. These ablative nozzle liners are processed from carbon phenolic/silica phenolic prepregs using a complex processing cycle. The process starts from impregnating the fibres with phenolic resin followed by either moulding or wrapping/winding prepreg tapes over metallic mandrels followed by polymerization under pressure. Traditionally, prepreg is cut into straight tapes and wound on mandrels to form the divergents. For throats and convergents, prepreg patterns are cut and stacked for curing. Plies of shape conforming to the development of base cone are cut from the prepreg and wound on the mandrel. After polymerization, the final required configuration is machined from this cylindrical blank after the liners are cured. The new method, described in this paper, replaces the straight-cut prepreg tapes by bias-cut prepreg tapes. These can be used for ablative liners in which the plies are at an angle to the direction of the flow. Bias tapes are cut at 45° to the warp and weft directions of the fabric to the required width and formed to the required frustum of cone. Since the cone is formed from straight cut bias tape, the fibre construction will be uniform around the circumference unlike the pattern cut tape. The efficiency of this process depends on the wrapping ratio which is in turn a function of the diameter, ply angle and tape width. To get the best wrapping ratio, shaped mandrels are used which brings down the material wastage and machining allowances. This paper describes the attempts to develop the Bias wrapping technology for angle wound liners. The details of process trials, challenges faced and how they were overcome, advantages of the process over conventional process etc are explained. Exhaustive material characterization of the material was done. Property comparison and validation of performance in subscale tests and a full scale static test are also discussed. The analysis indicates that this new technology has good potential in replacing the traditional tape-winding technology for rocket motor nozzle liners.

Microstructure and tensile properties of carbon–epoxy laminates produced by automated fibre placement: Influence of a caul plate on the effects of gap and overlap embedded defects

Automated fibre placement (AFP) enables the trajectory of unidirectional composite tape to be optimized, but laying down complex shapes with this technology can result in the introduction of defects. The aim of this experimental study is to investigate the influence of gaps and overlaps on the microstructure and tensile properties of carbon–epoxy laminates. First, a comparison between a hand-layup and AFP layup, draped and cured under the same conditions, shows equivalent microstructures and tensile properties. This provides the reference values for the study. Then, gap and overlap embedded defects (more or less severe) are introduced during manufacturing, on two cross-ply layups [(0°/(90°)5/0°] and [(90°/0°)2/90°]. Autoclave cure without a caul plate results in local thickness variation and microstructural changes which depend on the defect type. This has a strong influence on mechanical performance. Use of a caul plate avoids these variations and in this case embedded defects hardly affect tensile properties.

Theory analysis of critical-current degeneration in bended superconducting tapes of multifilament composite Bi2223/Ag

This paper proposed a degradation model to explore the influence of the mechanical bending deformation on the critical-current of superconducting composite Bi2223/Ag tape taking into account the asymmetric mechanical damage. With the aid of Weibull distribution function of statistical damage of filaments, the critical-current dependence upon bending strain of the superconducting tape in processes of loading and unloading is characterized. The degradation profile of critical-current in the superconducting composite tape is theoretically investigated by the proposed model for different critical damage strains and configurations of superconducting multifilament core at the cross-section. It is shown that the theoretical predictions are in reasonably good agreement with the experimental data, and the configuration of the multifilament core of the superconducting composite tape has a significant influence on the critical-current degradation. The superconducting multifilament core located near the compression region of the cross-section remarkably improves the mechanical and carrying-current capabilities of the superconducting composite tape.

Oriented Poly(lactic acid)/Carbon Nanotube Composite Tapes with High Electrical Conductivity and Mechanical Properties

Oriented poly(lactic acid) (PLA)/multiwall carbon nanotube (MWNT) tapes are prepared by solid-state drawing. These tapes showed significant morphological, mechanical and electrical property changes after drawing, with polymer crystallinity, nanotube dispersion and alignment being improved. Interestingly, the presence of the MWNTs perturbed the orientation of the crystalline polymer chain domains. Drawing lowered the electrical conductivity and increased the percolation threshold of the nanocomposites, but micromechanical analysis showed that it greatly improved the reinforcing efficiency of the MWNTs. This resulted in an overall good balance with one of the best compromises in terms of high mechanical properties and electrical properties for conductive polymer composite tapes.

Placement suitability criteria of composite tape for mould surface in automated tape placement

Automated tape placement is an important automated process used for fabrication of large composite structures in aeronautical industry. The carbon fiber composite parts realized with this process tend to replace the aluminum parts produced by high-speed machining. It is difficult to determine the appropriate width of the composite tape in automated tape placement. Wrinkling will appear in the tape if it does not suit for the mould surface. Thus, this paper deals with establishing placement suitability criteria of the composite tape for the mould surface. With the assumptions for ideal mapping and by applying some principles and theorems of differential geometry, the centerline trajectory of the composite tape is identified to follow the geodesic. The placement suitability of the composite tape is examined on three different types of non-developable mould surfaces and four criteria are derived. The developed criteria have been used to test the deposition process over several mould surfaces and the appropriate width for each mould surface is obtained by referring to these criteria.

Development of Composite RABiTS Tapes for Coated Conductors

Substrate materials are the key element of the coated conductors. There are two types of substrates-nontextured (stainless steel (SS) or Hastelloy alloys) and textured ones which are based on the Ni-W alloys. The main requirements for the textured tapes (RABiTS) are the presence of the highly pronounced biaxial cubic texture {100} and low values of magnetic susceptibility. To realize these requirements RABiTS tapes of various kinds were developed-homogenous tapes from Ni-W alloys with W content 5.5-9 at.% and composite ones. Composite tapes consist of three layers-one of SS and two of Ni-W alloy with W content 6 at.%. Mechanical and magnetic properties of the tapes were investigated and the dependence of tapes texture quality from total accumulated deformations was studied. The ultimate tensile strength value of composite tapes was 750± 10 MPa. The conditions necessary to form the required {100} texture are different for the homogeneous and composite tapes. According to the magnetic measurements saturation magnetization of composite tapes is about a factor of two lower than for similar homogeneous tapes.

Hysteretic Magnetization Losses of HTSC Tapes in Coaxial AC and DC Magnetic Fields

In the work we present experimental results of ac magnetization losses measurements performed in the presence of a dc-bias magnetic field. Both ac and dc magnetic fields were coaxial and directed perpendicularly to the flat surface of sample tapes. The HTS tapes used in our experiments are commercially available composite tapes, namely a BSCCO-2223/Ag multifilamentary tape and an YBCO-123 coated conductor tape. The measurements were carried out with a sinusoidally varying magnetic fields at frequency range of about 21-113 Hz, and amplitudes up to 100 mT. The superimposed a dc-bias magnetic field was of the order of up to 50 mT. At a certain magnetic field amplitude, and at a certain dc bias magnetic field, a distinguish minimum in ac losses is observed. Occurrence of the ac loss minima differs considerably for two studied sample tapes.

Toward a Tunable Fibrous Scaffold: Structural Development during Uniaxial Drawing of Coextruded Poly(ε-caprolactone) Fibers

A continuous fibrous composite tape of poly(ethylene oxide) (PEO) and poly(e-caprolactone) (PCL) was produced using novel multilayer coextrusion fiber manufacturing. A three-step washing process was utilized to remove the PEO matrix, resulting in a PCL fiber mat (>99 wt %). Synchrotron X-ray radiation was utilized to determine the optimized postprocessing uniaxial drawing conditions to achieve efficient crystalline orientation. An examination of small-/wide-angle X-ray scattering (SAXS/WAXS) revealed two regimes in the uniaxial drawing process; at DR 5, amorphous chain alignment kinetics were dominant. Uniaxial drawing was shown to be an effective tool for tuning individual fiber size from 2.6 ± 0.6 μm by 1.6 ± 0.4 μm in the as-extruded state to 0.31 ± 0.05 μm by 0.13 ± 0.02 μm in the oriented state, while increasing specific surface area 3.5-fold. The elastic modulus and tensile strength of the PCL fiber mat were also increased by a facto...