bluuebunny/crossref_metadata_2025 huggingface dataset:
Manufacture of Composite Panel from Sugarcane Bagasse
Authors: Shahidan Nor Suhaina , Muhammed Suhaimi
Published: February 2011

Agricultural waste such as sugarcane bagasse is abundant in Malaysia and at present is mainly used as combustible material for energy supply in the sugar factory. This study was conducted to investigate the possibility of manufacturing composite panel from sugarcane bagasse at three density levels (450, 550, 650 kg/m3), two resin content (10 and 12%) and with or without wax (1%) addition. The panel produced were tested for mechanical properties (modulus of elasticity and modulus of rupture) and physical properties (water absorption and thickness swelling) conforming to the British standard (BS EN 310 and BS EN 317). The results revealed that board with density 650kg/m3 gave superior strength compared to those of 450kg/m3 and 550kg/m3 densities. The addition of 1% wax helped to improve the water absorption and thickness swelling of the composite panel. Thus, it can be concluded that composite panel can successfully be produced from sugarcane bagasse as the main source of raw materials.
Investigation on Bending Strength and Stiffness of Sugar Palm Fibre from Different Parts Reinforced Unsaturated Polyester Composites
Authors: Sahari J. , Sapuan S.M. , Ismarrubie Z.N. , Rahman M.Z.A.
Published: February 2011

This investigation is done to select the best composite on bending strength and stiffness derived from different parts of sugar palm fibre reinforced unsaturated polyester composites. Sugar palm tree is one of the most popular natural fibres. The fibre was obtained from the sugar palm tree and mixed with unsaturated polyester (PE). All of the composites are labelled as SPF/PE for sugar palm frond composite, SPB/PE for sugar palm bunch composite, SPT/PE for sugar palm trunk composite and ijuk/PE for black sugar palm fibre composite. The bending strength and stiffness tests were done according to ASTM D 790-(2000). The higher value of bending strength and stiffness obtained by SPT/PE which is 41.906 MPa and 3.363 GPa respectively followed by SPF/PE (38.906 MPa and 3.001 GPa), SPB/PE (35.168 MPa and 2.749) and ijuk/PE (33.742 MPa and 2.424 GPa)
Rheological Behaviour of Polypropylene/Kenaf Fibre Composite: Effect of Fibre Size
Authors: Khalina Abdan , Zainuddin E.S. , Aji I.S.
Published: February 2011

In evaluating thermoplastics for their effective performance during processing, rheology properties are very useful. Similarly, in designing processing apparatus, knowledge of rheological behavior of composite melt is critical. In this study, melt flow and viscosity behavior of polypropylene/kenaf fibre composite was investigated using a single-screw extruder. Subsequently, flow behavior of the compounded formulation were evaluated by comparing the melt flow index, flow curve and viscosity curve of the PP and that of the composites at 190oC processing temperature and varying the fibre size. There appears to be a positive linear increase of the apparent shear stress with increase in the apparent shear rate and, as expected, viscosity values for the composite samples are much higher than the PP especially at larger fibre size. The additional of kenaf fibre in composite reduces the MFI value basically because of the hindrances in the plastic flow of the polymer. In addition the increase in viscosity with increase in fibre loading might contributed to the high specific area of the fibre in the matrix thereby increasing the shear stress in the composite. Moreover loading of polymer system with fibre tends to disturb or disorganize the normal free movement of the polymer and certainly hindered the mobility chain segments in flow.
Thermal Buckling and Post-Buckling Improvements of Laminated Composite Plates Using Finite Element Method
Authors: Rasid Zainudin A. , Amran Ayob , Zahari Rizal , Mustapha Faizal , Majid D.L. , Varatharajoo Renuganth
Published: February 2011

Thermal buckling and thermal post-buckling behaviours of laminated composite plates are improved by embedding shape memory alloy wires within laminates of composite plates. The procedure is to use the recovery stress that is induced when the reverse transformation of the shape memory alloy from martensite to austenite phases is constrained. For aerospace applications where the source of the shape memory alloy heating is the high temperature environment itself, a study is conducted to see the effect of shape memory alloy in improving the thermal buckling and post-buckling of composite plates. Due to the temperature dependent nature of the composite matrix and the shape memory alloy, the finite element formulation developed here is in the incremental form. Solving this non-linear model using the developed in-house source code, critical loads are determined and the post-buckling paths of the shape memory alloy composite plates are traced. This study shows that by embedding the shape memory alloy within composite plates, the thermal buckling and post-buckling behaviours of composite plates can be improved substantially.
Responses of PFRP Cantilevered Channel Beams under Tip Point Loads
Authors: Thumrongvut Jaksada , Seangatith Sittichai
Published: February 2011

In this paper, the experimental results on the structural behaviors of the pultruded fiber reinforced plastic (PFRP) cantilevered channel beams under tip point load are presented. The dimensions of the beam specimens are 76 22 6, 102 29 6 and 152 43 10 mm. The span-to-depth ratios of the specimens are in the range of 10 to 46. A total of 36 specimens were tested to investigate the effect of unbraced length of the beam on the behavior of lateral-torsional buckling and buckling load. Then, the obtained buckling loads were compared to the critical buckling loads calculated by using the modified classical beam theory. From the tests, it was found that the beams have linear elastic responses up to 90-95% of their buckling loads. The mode of failure of the specimens is in the form of lateral-torsional buckling. The modified Timoshenko and Gere’s equation unsatisfactorily predicts the critical buckling loads of the beams. Finally, by using a curve fitting, a modification factor was proposed, and the obtained test results and those calculated by the proposed modified equation are in good agreement.
Effect of Nanoclay on the Mechanical and Thermal Properties of Rigid Polyurethane/Organoclay Nanocomposite Foams Blown with Cyclo and Normal Pentane Mixture
Authors: Valizadeh M. , Rezaei M. , Eyvazzadeh A.
Published: February 2011

Polyurethane (PU)/Clay nanocomposite rigid foams were synthesized with modified layered silicate clay (organoclays, Cloisite 30B). PU foams were prepared by a batch reaction injection molding process. Organoclay was dispersed first in the isocyanate component using an ultrasonic homogenizer and then mixed with polyol and physical blowing agent mixture to produce nanocomposite PU foams. To study the reaction possibility between cloisite 30B and isocyanate as well as the effect of sonication on the reaction, Fourier transfer infrared (FTIR) analysis was conducted. The dispersion of organoclay in the rigid PU/clay nanocomposite foams was analyzed by wide angle X-ray diffraction (XRD). The microstructure of the foams was studied by an optical microscope and image analysis software. It was concluded that with increasing of nanoclay content the cell size is decreased and the cell size distribution is narrowed. The mechanical properties of pure and nanocomposite foams were examined by compression test. The data obtained from the compressive stress-strain curves reveals that the strength and modulus of polyurethane foam increase by addition of organoclay up to 1wt% and then decrease. Thermal conductivity coefficient (k-factor) of rigid PU nanocomposite and neat foams was measured by a simple transient method. The thermal conductivity results demonstrated that the polyurethane foam k-factor continuously decrease by addition of organoclay. It can be attributed to the reduced cell size as well as narrow cell size distribution in of nanocomposite foams.
Failure Modes of CFRP Flexural Strengthened Steel I-Beams
Authors: Narmashiri Kambiz , Jumaat Mohd Zamin , Ramli Sulong Nor Hafizah
Published: February 2011

This paper presents the experimental and numerical studies on the flexural strengthened steel I-beams by using Carbon Fiber Reinforced Polymer (CFRP) strips. Nowadays, strengthening existing steel structures by using CFRP has been widely interested. One of the common usages of CFRP to strengthen steel beams is the flexural upgrading. In this case, CFRP strips are pasted on the tensile flange to improve flexural behaviors. The problems that are frequently reported for CFRP strengthened steel beams are the debonding, delaminating (peeling), and splitting. Identification these failure modes are essential to provide an appropriate level of safety for strengthened steel beams. To investigate the CFRP failure modes, four strengthened steel I-beams were chosen. The CFRP plates with different thicknesses in single and double (splice) layers were used. Both experimental test (four-points bending test) and numerical simulation (full 3D simulation with ANSYS) were employed. The incremental loading was applied until failure while deformations in the critical regions were recorded. The results reveal that for the CFRP flexural strengthened steel beams the following failure modes occurred: (a) debonding at the CFRP plate tips, (b) debonding below point loads, (c) delaminating at the ends of CFRP plate, and (d) splitting below point loads. The sequence of failure modes depended on the specifications of CFRP plate. Some recommendations are provided to overcome/retard these failures.
Computer Simulation and Experimental Investigation of Solidification Casting Process
Authors: Suraya S. , Sulaiman Shamsuddin , Arifin Mohd Khairol A. , Sayuti Mohd
Published: February 2011

Computer simulation is widely used and conventional in manufacturing as a way to improve the manufactured goods quality as at same time plummeting invention costs, development time and scrap. In this study, three-dimensional model have been developed to simulate the filling and the solidification pattern in an aluminum casting with “AnyCasting” software. Using this software, solidification of aluminium 11.8% Si alloy in sand and metal mould was simulated and the results were compared with the experimental results. The solidification time and temperature was experimentally determined from thermocouple located at diverse distances. A data logger is used in experiment to gain the temperature division contour during the process of solidification of the aluminium 11.8% Si alloy. Experiments were set up to legalize the simulation results and it is confirm that the results from the two mould methods be in good agreement and the solidification of cast aluminium alloy using copper mould was much faster compared to the one cast sand mould. From this work it is concluded that simulation using AnyCasting software can be use to initially calculate. The simulation shows result that matches with the experimental data qualitatively and therefore the validation procedure is successful.
Manufacturing of Wood-Plastic Composite from Completely Recycled Materials
Authors: Tabarsa Taghi , Khanjanzadeh Hossein , Pirayesh Hamidreza
Published: February 2011

In this study, wastes of wood cutting mills (wood flour) as well as wastes of textile industry (granules of polypropylene) were used in manufacturing wood-plastic composites. Hence, wood flour with weight percent of 30, 35 and 40 was mixed with corresponding amount of polypropylene and coupling agent, polypropylene grafted maleic anhydride in amount of 6 percent was used in whole compounds. Production was done by batch method and with employment of hot press and after preparation and cutting of specimens physical and mechanical properties of them was studied. The results showed that with increase of wood flour up to 35 percent, MOR, MOE, water absorption and thickness swelling increases but further than it mechanical and physical properties decreases. Besides, increase of wood flour up to 40 percent increased the hardness of the specimens.
Analysis of MPV Dashboard Using SolidWorks and ABAQUS
Authors: Arifin Mohd Khairol A. , Hassan Nik Mohd Idham Nik , Abdullah Mohd Firdaus
Published: February 2011

The study is intended to measure the reliability of MPV dashboard to endure interior impact by using finite element analysis (FEA) method. A model which represents MPV dashboard was made using Solidworks and the impact simulation was done using ABAQUS. Current material being used for dashboard is ABS-GF40 and this material was proven to be reliable to withstand interior impact through the simulation that has been done in this study. Besides, this study also serve the purpose to reduce manufacturing cost using alternative materials with no less reliability compared to ABS-GF40. Similar simulation routines were applied for ABS copolymer, PP copolymer, and PVC copolymer. The simulation results showed that ABS-CF40 performance is similar to ABS-GF40, whereas the PP-CF10, PP-GF10, and PVC-GF30 exhibit almost identical behavior under impact loading. Cost assessment was carried out for all materials to assist in selecting alternative material for replacement of ABS-GF40. Hence, it was found that PP-GF10 can be used as an alternative material with cost reduction up to RM33.17 on each dashboard.
Residual Strength and Failure Criterion of PP Thermoplastic Honeycomb Sandwich Subjected to Low Velocity Impact
Authors: Amir A. Freeda , Othman A.R.
Published: February 2011

This paper presented the effect of constituent materials on impact damage and strength reduction of sandwich structure, composed of laminated woven E-glass facesheets and polypropylene thermoplastic honeycomb core. Effect of low-velocity impact was the main interest in a variety of layered configurations. Compression after impact (CAI) has been carried out to determine the residual strength of impacted sandwich structures. Three different thicknesses of core of 20, 40 and 60mm subjected to three different levels of impact energy of 15, 30 and 45J were investigated. Impact response of the panel was recorded and analyzed in terms of peak load, indentation, energy absorbed and time. A profile analysis using optical 3D surfaces profiler was carried out to attain the indentation depth and damage area of the samples. The tested samples were then sectioned into halves to capture the failure mode or damaged sequence of the polypropylene thermoplastic honeycomb core. The dominant failure modes of the core indicated that polypropylene thermoplastic honeycomb core is a high strength material which can absorb higher impact energy and retain a higher degree of structural integrity.
Mechanical Properties of Carbon Fiber-Reinforced Polypropylene Composites
Authors: Yunus Robiah Bt. , Zahari N.H. , Salleh M.A.M. , Ibrahim Nor Azowa
Published: February 2011

In this paper, the mechanical properties of carbon fiber polypropylene composites prepared under various process conditions were investigated. Two different types of polypropylene composites were produced by mixing and compressing the mixtures using hot press. The mixture was prepared by mixing polypropylene with chopped carbon fiber and carbon fiber percentage (wt%) was varied. Mechanical properties investigated were tensile test, impact test, bending test and density test. The Scanning Electron Microscopy (SEM) was employed to study the morphology of the composites. The highest tensile strength was obtained for polypropylene (MFI 60) composites reinforced with 10 wt% carbon fiber. The composite also exhibited the best tensile and flexural properties.
Free Vibration Analysis of Composite Sandwich Plate with Viscoelastic Core
Authors: Limouei Soroush Sadeghnejad , Sadighi Mojtaba , Ohadi Abdolreza
Published: February 2011

New Reddy-type elements based on Reddy’s higher-order theory are used in the analysis of composite sandwich plates with viscoelastic core, which is achieved by considering independent transverse displacements on two faces and linear variations through depth of plate core. In addition, Young modulus, rotational inertia, and kinetic energy of core are considered and core is assumed as 3D elastic structure with the properties of an orthotropic viscoelastic material. To improve the Reddy’s higher-order theory, a rectangular element with four nodes, which each node has seven degrees of freedom, is proposed. Hamilton’s principle has been used to obtain the equations of motion. A finite element code for structural response analysis of the free vibration is developed. The obtained results are compared with existence researches. The influence of material properties, lamination schemes, and fiber angle on natural frequencies of composite plates are investigated.
Tensile and Flexural Behavior of Hybrid Banana Pseudostem/Glass Fibre Reinforced Polyester Composites
Authors: Hanifawati I.N. , Azmah Hanim M.A. , Sapuan S.M. , Zainuddin E.S.
Published: February 2011

Natural fibre-based thermoset composites are generally lower in strength performance compared to synthetic thermoset composites. Hybridization with some amount of synthetic fibre enhanced the mechanical properties of the composites. This study focused on the performance of mechanical properties of hybrid banana/glass fibre reinforced polyester composites. Hybrid composites with different volume ratios of banana to glass fibre were prepared. The reinforcing effect of both fibres in polyester is also evaluated in various fibre loadings. Results showed that both flexural and tensile properties have been improved with the increasing level of overall fibre content loading. Tensile and flexural strength shows great enhancement by the introduction of a slight amount of glass fibre to the banana fibre polyester matrix.
Retrofitting Pre-Cracked RC Beams Using CFRP and Epoxy Injections
Authors: Hawileh Rami , Al-Tamimi Adil K. , Abdallah Jamal A. , Wehbi M.H.
Published: February 2011

The applications of Carbon Fiber Reinforced Polymers (CFRP) in construction have been grown drastically in the last 20 years because of the wide range of advantages and benefits of using CFRP in buildings, bridges and other type of structures. Nowadays, it is used for retrofitting concrete, masonry, steel and timber structures to resist both static and dynamic loads. Since the cost of replacing an existing structure is far more expensive than using FRP materials to strengthen it, CFRP strengthening techniques seem to be cost effective and easy to implement. Numerous experimental and numerical studies have been conducted to investigate the flexural and shear performance of uncracked reinforced concrete (RC) members externally strengthened with CFRP laminates or strips. However, the most practical usage of CFRP is to retrofit sections that had already been cracked and in need of maintenance. The fact that there have been limited studies to investigate the behavior and performance of pre-cracked beams strengthened with CFRP systems necessitated new and further investigations. In this study, the flexural performance of cracked RC beams retrofitted with CFRP plates and epoxy injections are investigated. The results of the cracked beams are compared with two control beams, a virgin un-strengthened beam and an uncracked beam strengthened with a CFRP plate covering 90% of the beam’s span. Load-midspan deflections for these beams were generated and compared. It is observed that the retrofitted cracked beams displayed more strength than the control beam. The results presented herein can aid designers in establishing a better understanding of the flexural performance of pre-cracked beams and how to economically retrofit such structural members.
Experimental and Numerical Investigation of Mixed-Mode Fracture Properties of Woven Laminated Composite
Authors: Heydari Mohammad Hossein , Choupani Naghdali
Published: February 2011

Delamination is a major problem associated with composite materials that reduce the stiffness of structure used in aerospace, marine and automotive technology. Interlaminar fracture toughness, non dimensional stress intensity factors and delamination crack growth behavior were investigated for carbon fiber (CF)-polyester laminates. All tests were performed with modified version of Arcan specimen. By changing the loading angles in range of 0-90°, mode-I, mode-II and all mixed mode fracture toughness data were obtained. Correction factors were obtained with finite element analysis using Abaqus software. By employing experimentally measured critical loads and the aid of the finite element method, mixed-mode fracture toughness for the composite under consideration determined. The fracture surfaces of the CF-P under different mixed-mode loading conditions were examined by optical and scanning electron microscopy (SEM) to gain insight into the failure responses.
Large Amplitude Thermo-Mechanical Vibration Analysis of Asymmetrically Laminated Composite Beams
Authors: Fallah Ali , Alavijeh Hamid Shahsavari , Pasharavesh Abdoreza , Aghdam Mohammad Mohammadi
Published: February 2011

In this paper, simple analytical expression is presented for large amplitude thermo-mechanical free vibration analysis of asymmetrically laminated composite beams. Euler-Bernoulli assumptions together with Von Karman's strain-displacement relation are employed to derive the nonlinear governing partial differential equation (PDE) of motion. He's variational method is employed to obtain a simple and efficient approximate closed form solution of the nonlinear governing equation. Comparison between results of the present work and those available in literature shows the accuracy of presented technique. Some new results for the nonlinear natural frequencies of the laminated beams such as the effect of vibration amplitude, lay-up configuration and thermal loading are presented for future references.
Effect of Nanoclay on the Physical-Mechanical and Thermal Properties and Microstructure of Extruded Noncross-Linked LDPE Nanocomposite Foams
Authors: Zandi F. , Rezaei M. , Kasiri A.
Published: February 2011

Novel noncross-linked low density polyethylene (LDPE) foams were produced by extrusion process. In this study the effects of Organophilic Montmorillonite (OMMT) nanoclay (DK1) on thermal conductivity, flame retardancy, morphological and mechanical properties of LDPE foams have been investigated. Nanoclay dispersion in LDPE foam structure was examined by X-ray diffraction (XRD), microstructure was observed by an optical microscope and analyzed by Bel View image analyzer, thermal conductivity was studied by a simple transient method, mechanical properties was investigated using a tensile-compression Zwick-Roell machine as well as the flame retardancy of the samples was examined by flammability test. The optimum nanoclay content was determined by comparison of the properties in nanocomposite and neat LDPE foams. Due to the presence of nanoclay in the foam and decreasing the cell nucleation energy around the nanoclay, the average cell size was decreased as well as the cell density and microstructure uniformity was increased. In XRD patterns of LDPE nanocomposite foams, OMMT (DK1) characteristic peak was not observed as evidence of nanoclay intercalation-exfoliation in the polymer matrix, which led to the production of foams with homogenous microstructure. Furthermore, this nanocomposites showed lower thermal conductivity compared to neat LDPE foam, which can be attributed to the cell size reduction as well as narrow cell size distribution in nanocomposite foams. Compression test results demonstrated that LDPE nanocomposite foams with proper clay contents have improved mechanical properties (Young’s modulus, compressive strength). Furthermore due to the presence of DK1 nanoclay, LDPE foam showed a good char formation as an evidence of their flame retardancy.
Interfacial Shear Strength of Polylactic Acid-Kenaf Fibre Biocomposites
Authors: Anuar Hazleen , Zuraida Ahmad , Morlin Bálint , Kovács József Gábor
Published: February 2011

This paper reported the interfacial shear strength (IFSS) between kenaf fibre (KF) and polylactic acid (PLA) matrix which was measured using microbond tests device. The value of IFSS obtained in PLA-KF is comparable to other polymer with natural fibre reinforcements. The properties of single kenaf fibre was determined from tensile tests and also described in this paper. From single kenaf fibre properties, various mechanical properties can be estimated for various applications.
Investigation of Hardness of Short Abaca (Musa Textile Nee) Fibre-Reinforced High Impact Polystyrene (HIPS) Composites by Response Surface Methodology
Authors: Agung E.H. , Sapuan S.M. , Megat Ahmad M.M.H. , Zaman Dahlan Khairul Mohd. , Mustofa U.
Published: February 2011

In this paper, the hardness property of abaca (Musa textile Nee) fibre reinforced high impact polystyrene (HIPS) composites with maelic anhydride (MAH) used as coupling agent and styrene butadiene styrene (SBS) copolymer rubber (Cyclo resin) used as impact modifier was investigated using response surface methodology.. The composites were initially fabricated using a rolling machine and finally using a hot press machine to obtain a desired thickness. These samples were then tested for Brinell hardness test. A statistical approach of response surface methodology was used to obtain the interaction between various compositions mentioned above for abaca fibre reinforced HIPS composites. The BHN (Brinell hardness number) was analyzed using response surface methodology (Box Behnken method).
Buckling Behavior of General Dome Ends under External Pressure, Using Finite Element Analysis
Authors: Abdi Behzad , Mozafari Hamid , Amran Ayob
Published: February 2011

In this paper, the finite element analysis is used to investigate the effect of shape of dome ends on the buckling of pressure vessel heads under external pressure. The Finite Element Analysis (FEA) with the use of elastic buckling analysis was applied to predict the critical buckling pressure. The influence of geometrical parameters such as thickness, knuckle radius, and the ratio of minor axis to the major axis of dome ends, on the weight and the critical buckling pressure of hemispherical, ellipsoidal, and torispherical dome ends, was studied. The four-centered ellipse method was used to describe the geometry of the dome end.
Simulation of Cracks in Fiber Reinforced Composite Plate
Authors: Kumar Pramod , Kakyal Ashish
Published: February 2011

Material flaws, pre-cracks and crack initiation due to cyclic loading often lead to undetected crack propagation in commercial structures like aircraft components, automotive parts and computer motherboard. Cyclic loading can make the crack grow large into any shape with an arbitrary orientation, depending on the structure geometry, boundary and loading conditions. Since crack propagation in many cases may lead to catastrophic failure with human and monetary loss as a result, it is important to enable crack growth prediction at all stages of development and during maintenance in order to prevent such scenarios. Micro mechanical approach is used for modelling the crack in composite materials. Crack propagation in a single edge crack plate is carried out by using FEM analysis. 2D model is analysed to determine the crack growth. The crack propagation rate, stress intensity factor and strain energy release rate are predicted by varying the crack length in fiber reinforced epoxy composite using NISA/ENDURE.
Fiber Reinforced Composite Structure with Bolted Joint – A Review
Authors: Jadee Khudhayer J. , Othman A.R.
Published: February 2011

Fiber reinforced composite structures are widely used in the aerospace, aircraft, civil and automotive applications due to their high strength-to-weight and stiffness-to-weight ratios and these applications require joining composite either to composite or to metal. There are three main methods for joining composite structures namely, bonding, mechanically fastened or a combination of the two. Bolted joint are preferred in structures where the disassembly is required for the purpose of maintenance and repair. Due to the stress concentration around the holes, bolted joints often represents the weakest part in the structure, and therefore it is important to design them safely. A review on the study of bolted joints in fiber reinforced composite structure is presented. It was found that the behavior of bolted joints in composite structure is affected by many factors, such as geometry, joint material, clamping–load provided by the bolts, ply orientations, etc. Accordingly, various researches have been conducted on the analyses of stress distribution, failure prediction, and strength properties of bolted joint both experimentally and numerically. Accurate prediction of stresses in bolted joints is essential for reliable design of the whole structure; if it is not optimally designed, premature and unexpected failures may be occurred.
Curing Characteristics, Fatigue Life and Morphological Properties of Natural Rubber Nanocomposites with Halloysite Nanotubes (HNTs)/Carbon Black (CB) Hybrid Filler
Authors: Salleh Siti Zuliana , Hanafi Ismail , Ahmad Zulkifli
Published: February 2011

In this research, natural rubber (NR) with halloysite nanotubes(HNTs)/carbon black (CB) hybrid filler at various filler loading was investigated where the total filler loading used in each compound were 40 phr. The curing characteristics, fatigue life and morphological properties of HNTs/CB/NR nanocomposites were studied. Laboratory two-roll mill was used for mixing process. The results revealed that vulcanizates containing more HNTs in hybrid filler exhibit longer scorch time (ts2) and cure time (t90) for curing characteristics and higher in fatigue life compared to vulcanizates with 40 phr of CB. The images from scanning electron microscope (SEM) confirmed that replacement of carbon black with halloysite nanotubes improved the fatigue life by showing more tearing surface on vulcanizates.
Damage Evolution in Structural Steel at Different Loading Conditions
Authors: Al-Himairee Reem Majeed , Abed Farid Hamid , Al-Tamimi Adil K.
Published: February 2011

This paper presents an experimental and numerical characterization of ductile damage evolution in steel subjected to large plastic deformations. The main objective of this research is to better understand damage initiation and evolution in structural steel throughout the deformation process at different strain rates. The proposed study relies on a continuum damage mechanics approach that involves characteristic parameters to describe the accumulation of plastic strain, the damage variable, and the strain rates. The work was divided into experimental, and simulation phases. The experimental phase involved testing under monotonic uniaxial tensile loading under varying strain rates. The obtained material parameters are then used as the basic data in the simulations that are performed afterwards. Finally, this model was implemented as a new user defined material in the finite element analysis software ABAQUS where damage was quantified. Initial results of this research showed that a simple model with substantial cost and time saving can be developed for damage assessment in steel. The rate of loading is a main sensitive parameter that affects both damage initiation and propagation, as they increased significantly with increasing loading rate. Beyond the ultimate load, the strain energy was sufficient to cause the damage to increase without any further applied load.
Modeling of Stiffness Reduction of Vibration Conveyor Springs Subjected to Ultra High Cyclic Loading under High Humidity
Authors: Yoshi Takahiko , Okubo Kazuya , Fujii Toru
Published: February 2011

Significant stiffness reduction of the plate spring due to delaminations around the interwoven cloths could be prevented by using CFRTP (carbon fiber cloth and Polyethylene Terephthalate (PET)) rather than that by using CFRP (carbon fiber cloth and epoxy), when ultra high cyclic loading was applied to the plate spring under high humidity condition. To explain the result, the prediction model of stiffness reduction was introduced considering time-dependent crack propagation accompanying with creep deformation around the crack tip. Stiffness reduction of CFRP under high humidity condition was not only determined by cyclic crack propagation but also by time-dependent crack propagation accompanying with creep deformation around the crack tip. It was found that CFRTP was effective material of the plate springs on vibration conveyer for the uses under high humidity condition to prevent significant stiffness reduction, where the crack propagation accompanying with creep deformation should be prevented around the crack tip.
Lay-Up Design of Low Wind Speed Composite Turbine Blade
Authors: Nugroho Indra H. , Judawisastra Hermawan , Suada M. Giri , Siswosuwarno Mardjono
Published: February 2011

Glass fiber reinforced polymer (GFRP) is a common composite material used for wind turbine blades because of its good strength to weight ratio. This paper describes the design process of GFRP material for a low wind speed (LWS) turbine blade. The wind turbine analyzed in this study is a 3-blades horizontal axis wind turbine (HAWT) with NACA 4415 airfoil and rotor diameter of 5 m. Parameters for the blade are thickness of skin and spar, lamination angle, and stacking sequence of the laminae. The design approach uses Carpet Plot Method based on Tsai-Hill failure criteria. Materials analyzed in this study are unidirectional E-glass fiber/epoxy composite and plain weave woven roving WR200 E-glass fiber/epoxy composite. There are 15 material configurations analyzed using a finite element software. The result shows top five of the composites configuration consisting of minimum 3 plies of 0°/90 direction fiber for the skin and ±45° direction fiber for the spar. The optimum configuration is [(0/90)]3 for the skin and (±45) for the spar both using plain weave woven roving WR200 E-glass fiber/epoxy composite. This configuration has margin of safety of 1.42 based on maximum principal stress and maximum deflection of 346 mm which is 0.14 of the total blade length. The predicted overall weight of the blade is 1.52 kg.
The Effect of Plastic Consolidation Parameters on the Microstructure and Mechanical Properties of Various Aluminium Powders
Authors: Tokarski Tomasz
Published: February 2011

The present paper is aimed at investigations of mechanical properties and structure of technical purity aluminum powders prepared by plastic consolidation process. The research work is focused on effective improvement of mechanical properties of material while keeping the conductivity at high level. It is well known that application of rapid solidification method with hot extrusion technique leads to grain refinement, as so according to Hall-Petch rule, improvement in mechanical properties of material can be expected. Furthermore, additional material strength can be obtained by aluminum oxides from free surface of powders that became internal boundaries during consolidation process. Aluminum powders atomized by air, argon and water were cold compacted and extruded at temperatures of 325°C and 375°C. For comparison purposes the same extrusion conditions were applied to cast aluminum. In order to analyze effect of recrystalization process during hot extrusion operation, different extrusion temperatures were chosen. Tensile tests as well as micro-hardnes measurements showed significant increase in mechanical strength for RS samples in comparison to conventionally cast material. Structural observations by means of transmission electron microscopy revealed that grain size of materials extruded at the given temperature was at the same level, however amount and distribution of oxides particles differs significantly. It was considered that differences in strength between individual RS material were attributed to this effect.
Wear Improvement of Pure Titanium Surface by TiB Precipitation after Plasma Alloying Process
Authors: Miklaszewski Andrzej , Jurczyk Mieczyslaw
Published: February 2011

Good mechanical properties with combination of biocompatibility and high corrosion resistance make titanium and its alloys desirable materials for medical applications. A big disadvantage of titanium connects with its poor wear characteristics, however in this work this property was modified by boride microplasma surface alloying. Plasma surface alloying gives a wide range of layer thickness, which is controlled by the amount of the placed powder and process parameters like gas flow, nozzle diameter and current. Formation of TiB phase precipitation was confirmed by XRD analysis. Additionally, the modified microstructure was observed by optical microscopy. The Vickers microhardness was significantly improved from 180HV for original titanium substrate to 900HV in obtained composite layer structure, with a smoth hardness reduction in the cross section profile. Strong heat penetration from microplasma melt-in technique, results in substrate dissolution with formation of stable composite Ti + TiB layer. The surface corrosion resistance in 0.9% NaCl solution was nearly the same as for pure titanium, showing stable behavior of created oxide layer, with no negative effect of dual phase microstructure. Wear resistance of received composite layer structures were significantly improved in comparison with initial titanium samples.
Corrosion Resistance of Nickel-Free Austenitic Stainless Steels and their Nanocomposites with Hydroxyapatite in Ringer's Solution
Authors: Tulinski Maciej , Jurczyk Mieczyslaw
Published: February 2011

In this work Ni-free austenitic stainless steels with nanostructure and their nanocomposites were synthesized by mechanical alloying (MA), heat treatment and nitriding of elemental microcrystalline Fe, Cr, Mn and Mo powders with addition of hydroxyapatite (HA). Microhardness and corrosion tests' results of obtained materials are presented. Mechanical alloying and nitriding are very effective technologies to improve the corrosion resistance of stainless steel. Decreasing the corrosion current density is a distinct advantage for prevention of ion release and it leads to better cytocompatibility. Similar process in case of nanocomposites of stainless steel with hydroxyapatite helps achieve even better mechanical properties and corrosion resistance. Hence nanocrystalline nickel-free stainless steels and nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g. orthopedic implants.
Effects of Annealing on Microstructure and Martensitic Transition of Ni-Mn-Co-In Ferromagnetic Shape Memory Alloys
Authors: Bałdys Katarzyna , Dercz Grzegorz , Madej Łukasz
Published: February 2011

The ferromagnetic shape memory alloys (FSMA) are relatively the brand new smart materials group. The most interesting issue connected with FSMA is magnetic shape memory, which gives a possibility to achieve relatively high strain (over 8%) caused by magnetic field. In this paper the effect of annealing on the microstructure and martensitic transition on Ni-Mn-Co-In ferromagnetic shape memory alloy has been studied. The alloy was prepared by melting of 99,98% pure Ni, 99,98% pure Mn, 99,98% pure Co, 99,99% pure In. The chemical composition, its homogeneity and the alloy microstructure were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The phase composition was also studied by X-ray analysis. The transformation course and characteristic temperatures were determined by the use of differential scanning calorimetry (DSC) and magnetic balance techniques. The results show that Tc of the annealed sample was found to decrease with increasing the annealing temperature. The Ms and Af increases with increasing annealing temperatures and showed best results in 1173K. The studied alloy exhibits a martensitic transformation from a L21 austenite to a martensite phase with a 7-layer (14M) and 5-layer (10M) modulated structure. The lattice constants of the L21 (a0) structure determined by TEM and X-ray analysis in this alloy were a0=0,4866. The TEM observation exhibit that the studied alloy in initial state has bigger accumulations of 10M and 14M structures as opposed from the annealed state.
Probing the Transition from Nano- to Bulk-Like Behaviour in ZnFe2O4 Nanoparticles
Authors: Moshopoulou Evagelia G. , Isnard Olivier , Milanovic Marija , Srdic Vladimir V.
Published: February 2011

The evolution of the magnetism as a function of the particle size is reported here for the ZnFe2O4 nanoparticles. A combination of neutron powder diffraction down to 1.5 K and magnetization measurements suggest that nanoparticles of sizes greater than about 100 nm exhibit bulk like behavior. The size dependence on magnetism can be explained by the rearrangement of the cations on the interstitial sites of the spinel cell.
Porous Titanium Scaffolds for Biomedical Applications: Corrosion Resistance and Structure Investigation
Authors: Dabrowski Bogdan , Kaminski Janusz , Swieszkowski Wojciech , Kurzydlowski Krzysztof J.
Published: February 2011

Due to its suitable physical properties and good biocompatibility, the titanium (Ti) can be used for development of porous structures for biomedical applications. The state of art in the field of corrosion resistance showed problems with corrosion analysis of porous metals. Therefore, it is essential to understand the influence of porosity of metals on corrosion parameters. The aim of this study was to investigate the corrosion resistance of highly porous titanium scaffolds for biomedical application. The Ti scaffolds were fabricated by powder metallurgy technique. The total porosity of the scaffolds ranged from 45 to 75%. The cast Ti sample was also tested for comparison. The electrochemical behavior of the Ti samples was monitored by electrochemical impedance spectroscopy (EIS) and potentiodynamic method at the room temperature. All electrochemical experiments were performed by a three-electrode technique in a cell containing a 0.9% NaCl electrolyte solution. With use of AAF, the active area of porous Ti was estimated. The porous Ti with porosity of 75% shows a better resistance to corrosion than the other porous Ti scaffolds. However, the corrosion resistance of Ti scaffolds was lower than cast Ti.
Structure and Functional Properties of Microcrystalline NiTi Alloy after Severe Deformation and Subsequent Annealing
Authors: Stróż Danuta , Dercz Grzegorz , Lekston Zdzisław , Rak Jan , Palka Jakub , Pawlicki Jacek
Published: February 2011

Thermomechanical treatment was applied to a binary NiTi alloy in order to improve its functional properties by forming nanocrystalline structure of the alloy. The alloy deformation was obtained by cold rolling combined with transverse movement of the rolls. This technique allowed us to obtain high strain (c ≈ 6) for the relatively large specimens. Subsequently, the samples were annealed in the temperature range 300 -500oC in order to form a nano-, submicro –and/or microcrystalline structure. The evolution of the structure and associated changes of the transformation sequences and functional properties were studied with the use of TEM, X-ray phase analysis, DSC and bend and free recovery ASTM tests. A mixed amorphous/crystalline structure was obtained after severe deformation, the martensitic transformation was completely suppressed in the sample. Annealing at lower temperatures caused formation of nanocrystalline structure that grew to the microcrystalline and finally well-defined polygonized structure in annealed at 500oC specimens.
The Deposition of Ni/Cr-Cr3C2 Composite Coatings by Arc-EB Hybrid Technology
Authors: Smolik Jerzy , Mazurkiewicz Adam
Published: February 2011

The new hybrid technology is a combination of electron beam evaporation and arcevaporation processes, enabling the creation of the anti-erosion multilayer composite coating Ni/Cr- Cr3C2 with different volume of Cr3C2 filling in soft Ni/Cr matrix. The soft matrix made of Ni/Cr alloy and hard filling of Cr3C2 are created at the same time and directly during the electron beam and arc-evaporation process. Changes of the parameters of the hybrid process, i.e. pressure, current of arc discharge and substrate bias voltage Ubias, make it possible to control the volume of Cr3C2 and are a factor in filling the soft Cr/Ni matrix with carbides Cr3C2. With the use of the developed surface treatment hybrid technology, the multilayer composite coating Ni/Cr-Cr3C2 were obtained. For all composite layers created, the material properties, such as morphology, phase and chemical compositions, hardness, and Young modulus were investigated. The paper presents the original technological equipment, methodology, and technological parameters for the creation of the composite coating Ni/Cr-Cr3C2.
Comparative Temperature Field Analysis of MgO Single Crystal Furnace Using Finite Element and Fuzzy Methods
Authors: Li Tie , Wang Zhen , Wang Ning Hui
Published: February 2011

This paper presents a method for calculating the temperature field distributions for MgO single crystal furnace. Finite element method (FEM) had been used to carry out the temperature field distributions of MgO single crystal furnace in terms of its energy consumption. Then fuzzy model of the furnace was developed using adaptive neuro-fuzzy inference system (ANFIS), for carrying out its temperature field analysis. Performance was evaluated by comparing finite element model with fuzzy model and good correlation was achieved between them.
Green Synthesis of Nano-Size Silver Particles Colloidal Sol
Authors: Chen Meng , Luo Shi Yong , Xu Wen Cai , Zhang Xin Lin
Published: February 2011

Using starch as the stabilizing agent, glucose as reducing agent, nano-size silver particles colloidal sols have been synthesized via ultrasonic irritation in aqueous solution. The synthesis process is completely green and the colloidal sols are safe to environment and human, and can be used as antibacterial agent in biology, medicine, food packaging and hauseware fields. The synthesis technology parameters for the silver particles with diameter of 15 to 45 nm, such as the ultrasonic power, reaction time, reaction temperature, concentrations of silver nitrate and capping agent were determined and discussed. The typical colloidal was characterized by ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscope (TEM), X-ray powder diffractometer (XRD) and Zeta Sizer Nano Series.
Propagation of SH Waves through an Interface between a Phononic Crystal and a Uniform Solid
Authors: Ci Long Sheng , Yu Gui Lan
Published: February 2011

The reflection and refraction of harmonic SH waves at the interface between a homogeneous solid and a one-dimensional phononic crystal is studied. The effects of wave frequencies on the refraction coefficients are investigated. The results show that for lower frequencies, most part of the energy is reflected into the homogeneous solid and that the frequency has little effects on the energy distribution at the interface. While for higher frequencies, SH waves cannot propagate in some directions because of the existence of the directional band gaps, which results in the discontinuity in the refraction coefficient curve. For waves passing through the interface, the higher the frequency is, the smaller the refraction coefficient is.