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1 – 10 of over 1000Abstract
Purpose
The objective of the present work is to ascertain the failure modes under different loading speeds along with change in percentage of constituents of FRP composites.
Design/methodology/approach
This involves experimental investigation of FRP composites with woven roving fibers and matrix. Different types of composites, i.e. glass: epoxy, glass: polyester and (carbon+glass): epoxy are used in the investigation with change in percentage of constituents. The variability of fiber content of the composite is in the range of 0.55‐0.65 weight fractions. The matrix dominated property, like inter laminar shear strength (ILSS) has been studied by three point bend test using INSTRON 1195 material testing machine with increasing five cross head velocities.
Findings
The variation of ILSS of laminates of FRP composites is significant for low loading speed and is not so prominent for high speed. The variation of ILSS are observed to be dependent on the type and amount of constituents present in the composites. The laminates with carbon fiber shows higher ILSS than that of glass fiber composites. The laminates with epoxy matrix shows higher ILSS than polyester matrix composites for the same fiber. There is no significant variation of ILSS beyond loading speed 200 mm/min and this can be used for specifications of testing. Matrix resins such as polyester and epoxy are known to be highly rate sensitive. Carbon fiber are relatively rate independent and E‐glass fibers are rate sensitive. Woven roving carbon glass fiber reinforced polymer shows small rate dependence and woven roving glass fiber reinforced polymer shows significant rate sensitivity.
Originality/value
The findings are based on original experimental investigations in the laboratories of the institute and can be used for characterization of composites.
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Çağatay Özada, Merve Ünal, Eslem Kuzu Şahin, Hakkı Özer, Ali Riza Motorcu and Murat Yazıcı
This study produced epoxy-filled urea-formaldehyde (UF) microcapsules (MCs) and T-403 amine MCs using the in situ technique. The Taguchi method was used to determine the effects…
Abstract
Purpose
This study produced epoxy-filled urea-formaldehyde (UF) microcapsules (MCs) and T-403 amine MCs using the in situ technique. The Taguchi method was used to determine the effects of the control factors (temperature, stirring speed, core-shell ratio and surfactant concentration) affecting MCs’ core diameter and core content and optimizing their optimum levels with a single criterion. Optimum control factor levels, which simultaneously provide maximum core diameter and core content of MCs, were determined by the PROMETHEE-GAIA multi-criteria optimization method. In addition, the optimized MC yield was analyzed by thermal camera images and compression test.
Design/methodology/approach
Microcracks in materials used for aerospace vehicles and automotive parts cause serious problems, so research on self-healing in materials science becomes critical. The damages caused by micro-cracks need to heal themselves quickly. The study has three aims: (1) production of self-healing MCs, mechanical and chemical characterization of produced MCs, (2) single-criteria and multi-criteria optimization of parameters providing maximum MC core diameter and core content, (3) investigation of self-healing property of produced MCs and evaluation. Firstly, MCs were produced to achieve these goals.
Findings
The optimized micro cures are buried in the epoxy matrix at different concentrations. Thermal camera images after damage indicate the presence of healing. An epoxy-amine MC consisting of a 10% by weight filled aluminum sandwich panel was prepared and subjected to a quasi-static compression test. It was determined that there is a strong bond between the UF shell and the epoxy resin.
Originality/value
The optimization of production factors has been realized to produce the most efficient MCs that heal using less expensive and more accessible methods.
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Payman Sahbah Ahmed, Ava A.K. Mohammed and Fakhir Aziz Rasul Rozhbiany
The purpose of this study is to get benefits from manufacturing harmful wastes is by using them as a reinforcement with epoxy matrix composite materials to improve the damping…
Abstract
Purpose
The purpose of this study is to get benefits from manufacturing harmful wastes is by using them as a reinforcement with epoxy matrix composite materials to improve the damping characteristics in applications such as machine bases, rockets, satellites, missiles, navigation equipment and aircraft as large structures, and electronics as such small structures. Vibration causes damaging strains in these components.
Design/methodology/approach
By adding machining chips with weight percentages of 5, 10, 15 and 20 Wt.%, with three different chip lengths added for each percentage (0.6, 0.8 and 1.18 mm), the three-point bending and damping characteristics tests are utilized to examine how manufacturing waste impacts the mechanical properties. Following that, the optimal lengths and the chip-to-epoxy ratio are determined. The chip dispersion and homogeneity are assessed using a field emission scanning electron microscope.
Findings
Waste copper alloys can be used to enhance the vibration-dampening properties of epoxy resin. The interface and bonding between the resin and the chip are crucial for enhancing the damping capabilities of epoxy. Controlling the flexural modulus by altering the chip size and quantity can change the damping characteristics because the two variables are inversely related. The critical chip size is 0.8 mm, below which smaller chips cannot evenly transfer, and disperse the vibration force to the epoxy matrix and larger chips may shatter and fracture.
Originality/value
The main source of problems in machine tools, aircraft and vehicle manufacturing is vibrations generated in the structures. These components suffer harmful strains due to vibration. Damping can be added to these structures to get over these problems. The distribution of energy stored as a result of oscillatory mobility is known as damping. To optimize the serving lifetime of a dynamic suit, this is one of the most important design elements. The use of composites in construction is a modern method of improving a structure's damping capacity. Additionally, it has been demonstrated that composites offer better stiffness, strength, fatigue resistance and corrosion resistance. This research aims to reduce the vibration effect by using copper alloy wastes as dampers.
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Jenarthanan M.P., Karthikeyan Marappan and Giridharan R.
The need for seeking alternate materials with increased performance in the field of composites revived this research, to prepare and evaluate the mechanical properties of e-glass…
Abstract
Purpose
The need for seeking alternate materials with increased performance in the field of composites revived this research, to prepare and evaluate the mechanical properties of e-glass and aloe vera fiber-reinforced with polyester and epoxy resin matrices.
Design/methodology/approach
The composites are prepared by hand layup method using E-glass and aloe vera fibers with length 5-6 mm. The resin used in the preparation of composites was epoxy and polyester. Fiber-reinforced composites were synthesized at 18:82 fiber–resin weight percentages. Samples prepared were tested to evaluate its mechanical and physical properties, such as tensile strength, flexural strength, impact strength, hardness and scanning electron microscope (SEM).
Findings
SEM analysis revealed the morphological features. E-glass fiber-reinforced epoxy composite exhibited better mechanical properties than other composite samples. The cross-linking density of monomers of the epoxy resin and addition of the short chopped E-glass fibers enhanced the properties of E-glass epoxy fiber-reinforced composite.
Originality/value
This research work enlists the properties of e-glass and aloe vera fiber-reinforced with polyester and epoxy resin matrices which has not been attempted so far.
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Radhwan Bin Hussin, Safian Bin Sharif, Shayfull Zamree Bin Abd Rahim, Mohd Azlan Bin Suhaimi, Mohd Tanwyn Bin Mohd Khushairi, Abdellah Abdellah EL-Hadj and Norshah Afizi Bin Shuaib
Rapid tooling (RT) integrated with additive manufacturing technologies have been implemented in various sectors of the RT industry in recent years with various kinds of prototype…
Abstract
Purpose
Rapid tooling (RT) integrated with additive manufacturing technologies have been implemented in various sectors of the RT industry in recent years with various kinds of prototype applications, especially in the development of new products. The purpose of this study is to analyze the current application trends of RT techniques in producing hybrid mold inserts.
Design/methodology/approach
The direct and indirect RT techniques discussed in this paper are aimed at developing a hybrid mold insert using metal epoxy composite (MEC) in increasing the speed of tooling development and performance. An extensive review of the suitable development approach of hybrid mold inserts, material preparation and filler effect on physical and mechanical properties has been conducted.
Findings
Latest research studies indicate that it is possible to develop a hybrid material through the combination of different shapes/sizes of filler particles and it is expected to improve the compressive strength, thermal conductivity and consequently increasing the hybrid mold performance (cooling time and a number of molding cycles).
Research limitations/implications
The number of research studies on RT for hybrid mold inserts is still lacking as compared to research studies on conventional manufacturing technology. One of the significant limitations is on the ways to improve physical and mechanical properties due to the limited type, size and shape of materials that are currently available.
Originality/value
This review presents the related information and highlights the current gaps related to this field of study. In addition, it appraises the new formulation of MEC materials for the hybrid mold inserts in injection molding application and RT for non-metal products.
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D. Behera, S. Kar and A.K. Banthia
To evaluate the efficiency of modifying epoxy resin using phenol‐nonyl phenol based polymer (PNPF) for toughness improvement and optimise the results of such a modification.
Abstract
Purpose
To evaluate the efficiency of modifying epoxy resin using phenol‐nonyl phenol based polymer (PNPF) for toughness improvement and optimise the results of such a modification.
Design/methodology/approach
For effective toughening, various compositions were made by incorporating PNPF at different concentrations. The impact and adhesive strengths of the unmodified and modified epoxy networks were characterised.
Findings
The modification of epoxy resin using PNPF showed significant enhancement of impact and adhesive strengths over the unmodified one. The modification caused the formation of a chemical linkage between PNPF and resin which led not only to a phase separation, but also to formation of intrinsically strong chemical bonds across the PNPF phase/resin matrix interphase, which was the main cause of the improved impact and adhesive strengths. The optimum results were obtained at 10 phr (parts per 100 parts of epoxy resin) of modifier.
Research limitations/implications
The modifier, PNPF, used in the present context was synthesised from phenol, nonyl phenol and formalin using oxalic acid as catalyst.
Practical implications
The developed method provided a simple and practical solution to improving the toughness of a cured epoxy.
Originality/value
The method for enhancing toughness of a cured epoxy was novel and could find numerous applications in the surface coating and adhesive.
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Payman Sahbah Ahmed, Ava Ali Kamal, Niveen Jamal Abdulkader, Basim Mohammed Fadhil and Fuad Khoshnaw
Pipelines are subject to pits, holes and cracks after staying in service for a while, especially in harsh environments. To repair the pipelines, composite materials are used, due…
Abstract
Purpose
Pipelines are subject to pits, holes and cracks after staying in service for a while, especially in harsh environments. To repair the pipelines, composite materials are used, due to composite materials' low cost, high-corrosion resistance and easy handling. This study aims to investigate the reliability of the blister test for evaluating the bonding strength of multiwall carbon nanotube (MWCNT) on woven carbon-reinforced epoxy.
Design/methodology/approach
Flexural, hardness and Izod impact tests were used to evaluate MWCNT effect on the epoxy by adding different amounts, 0.2, 0.4, 0.6, 0.8 and 1 wt. %, of MWCNT, to be compared with pure epoxy.
Findings
The results showed that 0.8 wt.% gives the highest strength. The experimental results of 0.8 wt.% MWCNT reinforced carbon composite was compared with the finite element model under blister test, and the results showed high similarities.
Originality/value
Evaluation of the reliability and the advantages of MWCNT considering the high aspect ratio and high tensile strength, which is more than 15 times compared to steel, MWCNT enhances the strength, stiffness and toughness of epoxy used as a matrix in repairing pipelines, which leads to an increase in the resistance of composite materials against oil internal pressure before delamination.
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Sathiyamoorthy Margabandu and Senthil Kumar Subramaniam
The study aims to investigate the influence of fabric hybridization, stacking sequences and matrix materials on the tensile strength and damping behavior of jute/carbon reinforced…
Abstract
Purpose
The study aims to investigate the influence of fabric hybridization, stacking sequences and matrix materials on the tensile strength and damping behavior of jute/carbon reinforced hybrid composites.
Design/methodology/approach
The hybrid composites were fabricated with different sequences of fabric plies in epoxy and polyester matrix using a hand layup technique. The tensile and vibration characteristics were evaluated on the hybrid laminated composite models using finite element analysis (FEA), and the results were validated experimentally according to ASTM standards. The surface morphology of the fractured specimens was studied using the scanning electron microscope.
Findings
The experimental results revealed that the position of jute layers in the hybrid composites has a significant influence on the tensile strength and damping behavior. The hybrid composite with jute fiber at the surface sides and carbon fibers at the middle exhibited higher tensile strength with superior damping properties. Further, it is found that the experimental results are in good coherence with the FEA results.
Originality/value
The less weight and low-cost hybrid composites were fabricated by incorporating the jute and carbon fabrics in interply configurations. The influences of fabric hybridization, stacking arrangements and matrix materials on the tensile and vibration behavior of jute/carbon hybrid composites have been numerically evaluated and the results were experimentally validated.
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B.C. Samanta, T. Maity, S. Dalai and A.K. Banthia
To evaluate the mechanical properties of cured epoxy modified with amine terminated poly (ethylene glycol) benzoate (ATPEGB) along with the comparison of results with change in…
Abstract
Purpose
To evaluate the mechanical properties of cured epoxy modified with amine terminated poly (ethylene glycol) benzoate (ATPEGB) along with the comparison of results with change in chain length of ATPEGB.
Design/methodology/approach
ATPEGB prepared from poly (ethylene glycol) (PEG) of different molecular weights (200, 400 and 600) were used as modifiers for epoxy resin here. For effective toughening, different compositions were made by adding various concentration of each ATPEGB to epoxy. The impact, adhesive, tensile and flexural strengths of modified and unmodified epoxy were characterised and compared for each ATPEGB.
Findings
Modification of epoxy resin using each ATPEGB showed significant enhancement of mechanical strengths over unmodified epoxy. The modification caused a chemical linking between ATPEGB and resin which led not only to a phase separation but also to ensuring their intrinsically strong chemical bonds across the ATPEGB phase/resin matrix interface and this was the main cause to the improved mechanical strengths. The optimum results were obtained at 12.5 phr (parts per hundred parts of epoxy resin) concentration of each modifier.
Research limitations/implications
The modifiers, ATPEGB, used in the present context were synthesised from PEG of molecular weight 200, 400 and 600. Besides, it could be synthesised from PEG of molecular weight 4,000 and 20,000, etc. and modification of epoxy resin could also be studied effectively by using these.
Originality/value
The method for enhanced toughness of cured epoxy was novel and could find numerous applications as surface coating and adhesive onto an intricate structure.
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B.C. Samanta and T. Maity
The purpose of this paper is to find a new toughening agent for diglycidyl ether of bisphenol A (DGEBA) resin and to check effectiveness of this new toughening agent to obtain…
Abstract
Purpose
The purpose of this paper is to find a new toughening agent for diglycidyl ether of bisphenol A (DGEBA) resin and to check effectiveness of this new toughening agent to obtain toughness and chemical resistance of cured epoxy.
Design/methodology/approach
For this purpose, an investigation was carried out to synthesise, characterise and to study the toughening reaction of amine functional aniline furfuraldehyde condensate (AFAFFC) with DGEBA resin. AFAFFC was first synthesised from the reaction of aniline and furfuraldehyde in the acid medium (pH‐4) and characterised by FT‐IR spectroscopy, elemental analysis and concentration of primary and secondary amine analysis. Then various formulations were made by mixing DGEBA, AFAFFC and ambient temperature curing agent triethylene tetramine (TETA) in different compositions and the modified networks were evaluated to their mechanical and thermal properties. The dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) studies and thermogravimetric analysis (TGA) of toughened epoxy were also reported.
Findings
The resulting networks developed a two‐phase microstructure upon network formation and displayed significantly improved fracture toughness. The dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) studies showed two‐phase morphology in the cured networks where AFAFFC particles were dispersed. TGA showed that the AFAFFC modified epoxy network was thermally stable up to around 311°C.
Research limitations/implications
The toughening agent AFAFFC has been synthesised by using aniline and furfuraldehyde. By changing amine and aldehyde other toughening agents could be synthesised and efficiency of these toughening agent for epoxy resin could also be studied.
Originality/value
The method for toughening of epoxy resin (DGEBA) is novel and relevant, as the toughened products have high performance applications in protective coatings, adhesives for most substrates and matrix resins for composites.
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