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Function-Integrative Textile Reinforced Concrete Shells  [PDF]
Sandra Gelbrich, Henrik L. Funke, Lothar Kroll
Open Journal of Composite Materials (OJCM) , 2018, DOI: 10.4236/ojcm.2018.84013
Abstract:
This paper presents the development and technological implementation of textile reinforced concrete (TRC) shells with integrated functions, such as illumination and light control. In that regard the establishment of material, structural and technological foundations along the entire value chain are of central importance: From the light-weight design idea to the demonstrator and reference object, to the technological implementation for the transfer of the research results into practice. The development of the material included the requirement-oriented composition of a high-strength fine grained concrete with an integrated textile reinforcement, such as carbon knitted fabrics. Innovations in formwork solutions provide new possibilities for concrete constructions. So, a bionic optimized shape of the pavilion was developed, realized by four connected TRC-lightweight-shells. The thin-walled TRC-shells were manufactured with a formwork made of glass-fibre reinforced polymer (GFRP). An advantage of the GFRP-formwork is the freedom of design concerning the formwork shape. Moreover, an excellent concrete quality can be achieved, while the production of the precast concrete components is simple and efficient simultaneously. After the production the new TRC-shells were installed and assembled on the campus of TU-Chemnitz. A special feature of the research pavilions are the LED light strips integrated in the shell elements, providing homogeneous illumination.
The Role of Fibre Orientation on the Electromagnetic Performance of Waveguides Manufactured from Carbon Fibre Reinforced Plastic
Alexe Bojovschi;Kelvin J. Nicholson;Amir Galehdar;Paul J. Callus;Kamran Ghorbani
PIER B , 2012, DOI: 10.2528/PIERB12011110
Abstract: Aircraft skins manufactured from carbon fibre reinforced plastic (CFRP) can simultaneously support structural load and act as antennas. This offers the potential for disproportionately large antenna elements and arrays, and thus enhanced aircraft capability. The efficient design of such structures requires that the link between CFRP microstructure and electromagnetic performance be established. This paper presents a method of predicting the electromagnetic attenuation of waveguides manufactured from CFRP. The method considers both the orthotropic, complex conductivity of CFRP, high in the fibre direction and low transverse to it, and the local electric fields in waveguides, which vary with location and frequency. The method was validated experimentally using waveguides manufactured from aerospace grade IM7/977-3 prepreg tape with [0 90]s, [90 0]s and [±45]s ply stacking sequences.
Modern composite materials manufactured by pressure infiltration method  [PDF]
L.A. Dobrzański,M. Kremzer,M. Drak
Journal of Achievements in Materials and Manufacturing Engineering , 2008,
Abstract: Purpose: The purpose of this paper is to present the technique of manufacturing the composite materials based on porous ceramic preforms infiltrated by liquid aluminium alloy and examination of the structure and corrosion resistance of those materials.Design/methodology/approach: The material for investigations was manufactured by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC – AlSi12 was use as a matrix while as reinforcement were used ceramic preforms manufactured by sintering of Al2O3 Alcoa CL 2500 powder with addition of pore forming agents as carbon fibres Sigrafil C10 M250 UNS manufactured by SGL Carbon Group Company. To determine the corrosion resistance, corrosion test by potentiodynamic method were made consisting in registering the anode polarization curves using the measurements system consisting of the potentiostat PGP-201 working with the Radiometer Copenhagen VoltaMaster 4 software.Findings: The received results show the possibility of obtaining the new composite materials with required structure and corrosion resistance depends of the volume fraction of the reinforcing phase.Practical implications: The composite materials manufactured by the developed method can find application among the others in automotive, aircraft or marine industry as the alternative material for elements fabricated from unreinforced aluminium alloys.Originality/value: The obtained results show the possibility of manufacturing the composite materials by the method of porous sintered framework pressure infiltration based on the ceramic particles, characterized with the better corrosion resistance than aluminium alloy used as the matrix.
Aluminium matrix composites fabricated by infiltration method
L.A. Dobrzański,M. Kremzer,A.J. Nowak,A. Nagel
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN AC – AlSi12 aluminum alloy. Stereological and structure investigations of obtained composite materials were made on light microscope. The mechanical properties of obtained composite material were investigated in tensile strength test and hardness test.Findings: It was proved that developed technology of manufacturing of composite materials based on the porous ceramic Al2O3 preforms infiltrated by liquid aluminium alloy ensures expected structure and strength Hardness increased about twice compared to the matrix and this process can be used in practice.Practical implications: The presented metal matrix composites fabrication technology allows to obtain locally reinforced elements and near net shape products.Originality/value: Results show the possibility of obtaining the new aluminium matrix composite materials being the cheaper alternative for other materials based on the ceramic fibers.
Wear mechanisms of fibre reinforced composite materials based on 2024 and 7075 aluminum alloys  [PDF]
K. Naplocha,J.W. Kaczmar
Journal of Achievements in Materials and Manufacturing Engineering , 2011,
Abstract: Purpose: Determination of fibre reinforcement influence on wear rate and wear mechanisms were examined. Moreover, effect of fibre orientation and specimen pressure on the counterpart were analyzed.Design/methodology/approach: Composite materials based on 2024 and 7075 aluminium alloys were reinforced with 10-20 vol. % of alumina Saffil fibres and additionally choosen specimens with graphite fibres. Wear tests were carried out on pin-on-disc device where the specimens were pressed to the cast iron counterpart with forces corresponding to pressures of 0.8, 1.2 and 1.5 MPa.Findings: Wear mass loss for composite materials reinforced only with Saffil Al2O3 fibres decreased with increase of fibre content in the matrix. The largest wear rate in relation to the unreinforced alloy exhibited composites containing 20 vol. % of Saffil Al2O3 fibres, tested under the largest applied pressure of 1.5 MPa. The graphite fibres enhance the wear resistance of composite materials under all applied pressures. The lubricant medium originated form worn graphite fibres prevented composite from seizure and adhesive wear.Research limitations/implications: Fragmented alumina fibres acting as loose debris can enhance the wear rate both composite and iron counterpart. At high volume of graphite fibres produced preform possess low strength caused by weak joints between fibres.Practical implications: Composite 2024 and 7075 materials reinforced with hybrid preforms produced from alumina and graphite fibres exhibit good wear resistance.Originality/value: Manufactured composite materials will be considered as the friction materials for the high duty brakes.
Novel tests and inspection methods for textile reinforced composite tubes  [PDF]
W. Hufenbach,L. Kroll,M. Gude,A. Czulak
Journal of Achievements in Materials and Manufacturing Engineering , 2005,
Abstract: Purpose: This paper describes innovative lightweight applications of fiber and textile reinforced polymers in aircraft, automotive and chemical industry.Design/methodology/approach: This paper deals with modern test methods of braided composite tube specimens as basic elements of modern composites. The tubes subjected to strength tests under superposed compressive, tensile and internal pressure loadings, and tested by the acoustic emission method for damage detection.Findings: For the quality assessment and here, especially for the verification of fibre orientations after manufacture, the X-ray method is an advantageous inspection method. For the identification of fracture modes, after uni- and biaxial mechanical test under tensile, compressive and torque loads as well under inner pressure loading the computer tomography CT is used. The acoustic emission to assess for damage detection in braided composite pipes, and mechanical loading. Moreover, from the applied techniques the information concerned quality of a manufactured specimen, damage propagation and determination the types of damages can be obtained.Research limitations/implications: Those three methods assure very good and promising results having one limitation in case of volume of a tested sample, e.g in the CT device, an allowable diameter of an investigated tubular specimen amounts to 150mm.Practical implications: Use of the methods resulted in improved efficiency of test process and analysis of GFRP tubular specimens.Originality/value: The paper describes the new implicated test and inspection methods for textile reinforced composite tubes.
Unsymmetrical Fibre-Reinforced Plastics for the Production of Curved Textile Reinforced Concrete Elements  [PDF]
Henrik L. Funke, Sandra Gelbrich, Andreas Ehrlich, Lars Ulke-Winter, Lothar Kroll
Open Journal of Composite Materials (OJCM) , 2014, DOI: 10.4236/ojcm.2014.44021
Abstract: A new constructive and technological approach was developed for the efficient production of large-dimensioned, curved freeform formworks, which allow the manufacturing of single and double-curved textile reinforced concrete elements. The approach is based on a flexible, multi-layered formwork system, which consists of glass-fibre reinforced plastic (GFRP). Using the unusual structural behavior caused by anisotropy, these GFRP formwork elements permit a specific adjustment of defined curvature. The system design of the developed GFRP formwork and the concrete-lightweight-elements with stabilized spacer fabric was examined exhaustively. Prototypical curved freeform surfaces with different curvature radii were designed, numerically computed and produced. Furthermore, the fabric’s contour accuracy of the fabric was verified, and its integration was adjusted to loads.
Use of modern methods of fibre surface modification to obtain the multifunctional properties of textile materials  [PDF]
Joci? Dragan,Jovan?i? Petar,Radeti? Maja M.,Topalovi? Tatjana
Hemijska Industrija , 2003, DOI: 10.2298/hemind0310491j
Abstract: The modern textile fibre treatments aim to obtain the required level of beneficial effect while attempting to confine the modification to the fibre surface. Recently, much attention has been focused on different physical methods of fibre surface modification, cold plasma treatment being considered as very useful. Moreover, there are efficient chemical methods available, such as peroxide, biopolymer and enzyme treatment. Some interesting combinations of these physical and chemical surface modification methods as means to modify fibre surface topography and thus controlling the surface-related properties of the fibre are presented in this paper. The properties obtained are discussed on the basis of the physico-chemical changes in the surface layer of the fibre, being assessed by wettability and contact angle measurements, as well as by FTIR-ATR and XPS analysis. The SEM and AFM technique are used to assess the changes in the fibre surface topography and to correlate these changes to the effectiveness, uniformity and severity of the textile fibre surface modification treatments.
THE PRODUCTION OF FOAM ALUMINIUM ALLOY BY LOW-PRESSURE INFILTRATION METHOD
Y Zhang,ZD Zhao,JC Ding,
Y. Zhang
,Z.D. Zhao and J.C. Ding

金属学报(英文版) , 1999,
Abstract: The influence of technical parameters on the infiltrating height of the moltenmetal in the process of Producing aluminium alloy foam by low-pressure infiltration method were investigated.Experiments indicated that the height increases with the preheating temperature of granules,theexternal pressureand the pouring temperature of molten alloy,among which the action of pre heating temperature of granules is more effective.There exists a critical pre heating temperature for different size of granules.
Application of pressure infiltration to the manufacturing of aluminium matrix composite materials with different reinforcement shape  [PDF]
L.A. Dobrzański,M. Kremzer,A. Nagel
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: The purpose of this work is to investigate the influence of reinforcing phase’s shape on structure and properties of composite materials with aluminium alloy matrix.Design/methodology/approach: The material for studies was produced by a method of pressure infiltration of the porous ceramic framework. In order to investigate the influence of reinforcing phase’s shape the comparison was made between the properties of the composite material based on preforms obtained by Al2O3 Alcoa CL 2500 powder sintered with addition of pore forming agent in form of carbon fibres Sigrafil C 10 M250 UNS from Carbon Group company and composite materials based on much more expensive commercial fibrous preforms. The matrix consisted of cast aluminium alloy EN AC – AlSi12. The observations of the structure were made on the light microscope and in the scanning electron microscope. The strength properties were established on the basis of static tensile tests.Findings: The composite materials, obtained on the basis of ceramic preforms consisted of Al2O3 particles, are showing better strength properties in comparison to materials obtained by the fibrous preform infiltration.Practical implications: The composite materials made by the developed method can find application as the elements of devices where beside the benefits from utilizable properties the small weight is required (mainly in aircraft and motorization industries).Originality/value: The obtained results show the possibility of manufacturing the composite materials by the method of porous sintered framework pressure infiltration based on the ceramic particles, characterized with the better properties than similar composites reinforced with fibres.
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