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Development of novel piezoceramic actuator modules for the embedding in intelligent lightweight structures  [PDF]
W. Hufenbach,M. Gude,N. Modler,C. Kirvel
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: Piezoceramic actuators in lightweight structures enable a purposeful manipulation of the dynamic and vibroacoustic structural behaviour. Above it, further studies focus on the application of thin and flexible piezoceramic modules as power sources in morphing structures aiming at a shape adaptation.Design/methodology/approach: A specific example of novel morphing structures is introduced, which rely on multistable deformation phenomena of fibre-reinforced composites with an unsymmetric lay-up. For the large-scale capable utilisation of such active struc tural parts made of fibre-reinforced thermoplastic composites, novel piezoceramic modules, which are specifically tailored to the structural material, and required manufacturing methods are developed.Findings: The piezoceramic modules with the highly regarded compatibility to ther moplastic composites permit their substantially coherent and homogeneous integration in the fibre composite structure without intricate adhesive assembly effort. Furthermore, thermally induced residual compressive stresses during the manufacturing process serve for pur posefully prestressing the piezoceramic components to reduce the module’s sensitivity to tensile loading.Research limitations/implications: For the manufacture of those novel piezoceramic modules, a continuously operating fabrication method has been developed. By the process-related integration of a hot press, residual compression stresses are thermally induced into the modules that considerably contribute to the decrease of the piezoceramic module’s sensitivity to tension.Originality/value: The successful development of the novel TPM offers a significant advancement in the efficieny within the large scale production of novel intelligent lightweight structures.
Effect of Particle Size and Concentration of Flyash on Properties of Polyester Thermoplastic Elastomer Composites  [PDF]
M.S. Sreekanth, V.A. Bambole, S.T. Mhaske, P.A. Mahanwar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.83021
Abstract: The performance of filled polymers is generally determined on the basis of the interface attraction of filler and polymers. Particulate filled polymer composites are becoming attractive because of their wide applications and low cost. In this study the effects of flyash with three varying particle size and filler concentrations (viz. 5 to 40 weight %) on the mechanical, thermal, electrical, rheological and morphological properties of polyester thermoplastic elastomer (Hytrel?) was investigated. Composites of polyester thermoplastic elastomer with varying concentrations of flyash were prepared by twin screw extrusion. Mechanical properties such as flexural strength and modulus increases with filler loading, where as tensile strength is found to be decrease with increase in flyash loading. Dielectric strength of composites also increases with flyash loading. Morphological studies revealed that there is good dispersion of filler in the polymer matrix. Thermal properties were found to be improved with flyash addition. Further, it was observed that the mechanical (flexural), thermal as well as electrical properties of composites improved with decrease in particle size of filler.
Green composites of thermoplastic corn starch and recycled paper cellulose fibers  [PDF]
Amnuay Wattanakornsiri,Katavut Pachana
Songklanakarin Journal of Science and Technology , 2011,
Abstract: Ecological concerns have resulted in a renewed interest in environmental-friendly composites issues for sustainabledevelopment as a biodegradable renewable resource. In this work we used cellulose fibers from recycled newspaper as reinforcementfor thermoplastic starch in order to improve its mechanical, thermal and water resistance properties. The compositeswere prepared from corn starch plasticized by glycerol (30% wt/wt of glycerol to starch) as matrix that was reinforcedwith micro-cellulose fibers, obtained from used newspaper, with fiber content ranging from 0 to 8% (wt/wt of fibers to matrix).Physical properties of composites were determined by mechanical tensile tests, differential scanning calorimetry, thermogravimetricanalysis, water absorption measurement and scanning electron microscopy. The results showed that higherfibers content raised the tensile strength and elastic modulus up to 175% and 292%, respectively, when compared to thenon-reinforced thermoplastic starch. The addition of the fibers improved the thermal resistance and decreased the waterabsorption up to 63%. Besides, scanning electron microscopy illustrated a good adhesion between matrix and fibers. Theseresults indicated that thermoplastic starch reinforced with recycled newspaper cellulose fibers could be fruitfully used ascommodity plastics being strong, cheap, abundant and recyclable.
Effect of Concentration of Mica on Properties of Polyester Thermoplastic Elastomer Composites  [PDF]
M. S. Sreekanth, V. A. Bambole, S. T. Mhaske, P. A. Mahanwar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.84024
Abstract: Particulate filled polymer composites are becoming attractive because of their wide applications and low cost. In this study the effects of mica with varying concentration on the mechanical, thermal, electrical, rheological and morphological properties of polyester thermoplastic elastomer (Hytrel?) was investigated. Composites of Hytrel? with varying concentrations (viz. 5 to 40 weight %) of mica were prepared by twin screw extrusion. Mechanical properties such as flexural strength and modulus were found to increase with mica concentration, whereas tensile strength was found to decrease at higher concentrations. Electrical and thermal properties of composite were found to increase with filler concentration. Morphological studies revealed that there is a good dispersion of filler in the polymer matrix at lower oncentrations.
Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites  [PDF]
Fatih Mengeloglu,Kadir Karakus
Sensors , 2008, DOI: 10.3390/s8010500
Abstract: Thermal behaviors of wheat straw flour (WF) filled thermoplastic compositeswere measured applying the thermogravimetric analysis and differential scanningcalorimetry. Morphology and mechanical properties were also studied using scanningelectron microscope and universal testing machine, respectively. Presence of WF inthermoplastic matrix reduced the degradation temperature of the composites. One for WFand one for thermoplastics, two main decomposition peaks were observed. Morphologicalstudy showed that addition of coupling agent improved the compatibility between WFs andthermoplastic. WFs were embedded into the thermoplastic matrix indicating improvedadhesion. However, the bonding was not perfect because some debonding can also be seenon the interface of WFs and thermoplastic matrix. In the case of mechanical properties ofWF filled recycled thermoplastic, HDPE and PP based composites provided similar tensileand flexural properties. The addition of coupling agents improved the properties ofthermoplastic composites. MAPE coupling agents performed better in HDPE while MAPPcoupling agents were superior in PP based composites. The composites produced with thecombination of 50-percent mixture of recycled HDPE and PP performed similar with theuse of both coupling agents. All produced composites provided flexural properties requiredby the ASTM standard for polyolefin-based plastic lumber decking boards.
Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites
Fatih Mengeloglu,Kadir Karakus
Sensors , 2008,
Abstract: Thermal behaviors of wheat straw flour (WF) filled thermoplastic compositeswere measured applying the thermogravimetric analysis and differential scanningcalorimetry. Morphology and mechanical properties were also studied using scanningelectron microscope and universal testing machine, respectively. Presence of WF inthermoplastic matrix reduced the degradation temperature of the composites. One for WFand one for thermoplastics, two main decomposition peaks were observed. Morphologicalstudy showed that addition of coupling agent improved the compatibility between WFs andthermoplastic. WFs were embedded into the thermoplastic matrix indicating improvedadhesion. However, the bonding was not perfect because some debonding can also be seenon the interface of WFs and thermoplastic matrix. In the case of mechanical properties ofWF filled recycled thermoplastic, HDPE and PP based composites provided similar tensileand flexural properties. The addition of coupling agents improved the properties ofthermoplastic composites. MAPE coupling agents performed better in HDPE while MAPPcoupling agents were superior in PP based composites. The composites produced with thecombination of 50-percent mixture of recycled HDPE and PP performed similar with theuse of both coupling agents. All produced composites provided flexural properties requiredby the ASTM standard for polyolefin-based plastic lumber decking boards.
Recycling and Fibre Reinforcement of Thermoplastic Wastes to Produce Composites for Construction Works  [cached]
P.M. Wambua,A.N. Mayaka,E.O.V. Odhong
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: Thermoplastics are among polymers that biodegrades very slowly over a very long period and can be regarded as nonbiodegradable despite their rapid accumulation in the environment. The use of plant natural fibres as reinforcement for thermoplastics to produce composites is an important area for research. In this study, composites of high density polyethylene wastes reinforced with wood flour, rice husks and bagasse fibers were prepared. The fibers were heated to reduce their moisture content and improve their compatibilities with heated high density polyethylene wastes so as to increase adhesion at the interface. Binders were used to improve interfacial strength of the composite. Composites were prepared by extrusion. From preliminary laboratory test results based on Fratios using ANOVA, optimal coupon was found to be wood flour mixed with high density polyethylene and polyurethane resin (X 17) heated to 210oC and extruded at 140oC. The final test results for mechanical properties for optimal wood flour, rice husks and bagasse composites respectively were: Tensile strength; 83.87, 74, and 62.73 MPa. Flexural strength; 26.73, 39and 15.22 MPa. Compressive; 225, 190.5 and 140 MPa and Impact; 78, 81 and 66 J/mm2. The use of binders significantly improved impact strengths and widely expanded the usage of such product to include light load structural applications thus offering alternative source of construction materials to supplement timber and hence save forests. The technology can create employment to thermoplastic waste collectors, fibre collectors and composite producers.
Application of Taguchi method in the optimisation of filament winding of thermoplastic composites  [PDF]
L.A. Dobrzański,J. Domaga?a,J.F. Silva
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: Purpose of this paper was to find the optimum parameters to produce Twintex tubes by filament winding.Design/methodology/approach: Taguchi approach was used for this design. The experiments were done with varying fibers temperature, winding speed, number of layers and roving. Thermoplastic composite rings were manufactured in the thermoplastic filament winding process at selected conditions. The glass and polypropylene fibers (Twintex ) were used to produce tubes. The influence of the main process parameters on tensile strength and also shear strength was assessed.Findings: As it is presented in this work, the machining parameters, number of layers and roving affect on shear and tensile strength. Fibres temperature is very significant parameter both in tensile strength and shear test. Research limitations/implications: The main objective of the present study was to apply the Taguchi method to establish the optimal set of control parameters for the tubes by filament winding. The Taguchi method is employed to determine the optimal combination of design parameters, including: fibers temperature, winding speed, number of layers and number of roving.Originality/value: This paper presents new results of optimisation using Taguchi method filament winding process parameters producing new tubes from the thermoplastic Twintex material.
Damage detection in laminar thermoplastic composite materials by means of embedded optical fibers
Kojovi? Aleksandar M.,?ivkovi? Irena D.,Brajovi? Ljiljana M.,Mitrakovi? Dragan
Hemijska Industrija , 2006, DOI: 10.2298/hemind0608176k
Abstract: This paper investigates the possibility of applying optical fibers as sensors for investigating low energy impact damage in laminar thermoplastic composite materials, in real time. Impact toughness testing by a Charpy impact pendulum with different loads was conducted in order to determine the method for comparative measurement of the resulting damage in the material. For that purpose intensity-based optical fibers were built in to specimens of composite materials with Kevlar 129 (the DuPont registered trade-mark for poly(p-phenylene terephthalamide)) woven fabric as reinforcement and thermoplastic PVB (poly(vinyl butyral)) as the matrix. In some specimens part of the layers of Kevlar was replaced with metal mesh (50% or 33% of the layers). Experimental testing was conducted in order to observe and analyze the response of the material under multiple low-energy impacts. Light from the light-emitting diode (LED) was launched to the embedded optical fiber and was propagated to the phototransistor-based photo detector. During each impact, the signal level, which is proportional to the light intensity in the optical fiber, drops and then slowly recovers. The obtained signals were analyzed to determine the appropriate method for real time damage monitoring. The major part of the damage occurs during impact. The damage reflects as a local, temporary release of strain in the optical fiber and an increase of the signal level. The obtained results show that intensity-based optical fibers could be used for measuring the damage in laminar thermoplastic composite materials. The acquired optical fiber signals depend on the type of material, but the same set of rules (relatively different, depending on the type of material) could be specified. Using real time measurement of the signal during impact and appropriate analysis enables quantitative evaluation of the impact damage in the material. Existing methods in most cases use just the intensity of the signal before and after the impact, as the measure of damage. This method could be used to monitor the damage in real time, giving warnings before fatal damage occurs.
BACTERIAL CELLULOSE REINFORCED THERMOPLASTIC COMPOSITES: PRELIMINARY EVALUATION OF FABRICATION AND PERFORMANCE
Ruijun Gu,Bohuslav V. Kokta,Katrin Frankenfeld,Kerstin Schlufter
BioResources , 2010,
Abstract: Mechanical properties of polyethylene (PE) composites were evaluated as a function of the addition of bacterial cellulose (BC). It was found that BC could improve the mechanical properties of the composites with or without the combination of traditional wood fiber. The improvements were affected by post-treatment. It was confirmed that BC had a significant influence on impact strength. The pellicle form of BC was able to achieve superior impact strength compared to the fluffy form of BC, but had similar effects on the tensile strength in comparison to the composites with fluffy BC.
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