Tensile strength of GFRP and hybrid composites under various environmental conditions

2018 ◽  
Vol 90 (6) ◽  
pp. 956-961
Author(s):  
Praveen Shaju Chelladhurai

Purpose The purpose of this paper is to study the mechanical behavior of glass fiber reinforced polymer (GFRP) and hybrid composites under various adverse environmental conditions. This mainly helps the researchers to overcome the obstacles that have been met when they use the materials individually and also to know the impacts of environment on them. Design/methodology/approach The GFRP and hybrid specimens are made according to the American Society for Testing and Materials standard. The specimens are then immersed in aviation turbine fuel, hydraulic fluid and concentrated sulfuric acid. The tensile strength of the specimens is then determined using the universal testing machine. Findings The tensile strengths of the normal specimens and the specimens subjected to various environmental conditions are determined. The results obtained for GFRP and hybrid specimens are then compared. Research limitations/implications The researchers can extend the time intervals further for a better understanding of the strength of the composites. Practical implications Once better combinations are found out with the highest strength to weight ratio and its resistance to various adverse environmental conditions, it can be used in real-time applications. Social implications The best hybrid combinations can be used in place of metals in future. Originality/value This is an original research and is clearly based on the experimental results, so it adds very much value to the aviation industry because strength to weight ratio is one of the major issues to be taken into consideration.

2020 ◽  
Vol 10 (3) ◽  
pp. 281-292 ◽  
Author(s):  
Saurabh Dewangan ◽  
Suraj Kumar Mohapatra ◽  
Abhishek Sharma

PurposeTitanium (Ti) alloys are in high demand in manufacturing industries all over the world. The property like high strength to weight ratio makes Ti alloys highly recommended for aerospace industries. Ti alloys possess good weldability, and therefore, they were extensively investigated with regard to strength and metallurgical properties of welded joint. This study aims to deal with the analysis of strength and microstructural changes in Ti-6Al-4V (Grade 5) alloy after tungsten inert gas (TIG) welding.Design/methodology/approachTwo pair of Ti alloy plates were welded in two different voltages, i.e. 24 and 28 V, with keeping the current constant, i.e. 80 A It was a random selection of current and voltage values to check the performance of welded material. Both the welded plates were undergone through some mechanical property analysis like impact test, tensile test and hardness test. In addition, the microstructure of the welded joints was also analyzed.FindingsIt was found that hardness and tensile properties gets improved with an increment in voltage, but this effect was reverse for impact toughness. A good corroboration between microstructure and mechanical properties, such as tensile strength, hardness and toughness, was reported in this work. Heat distribution in both the welded plates was simulated through ANSYS software to check the temperature contour in the plates.Originality/valueA good corroboration between microstructure and mechanical properties, such as tensile strength, hardness and toughness, was reported in this study.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 193
Author(s):  
M.H. Faisal ◽  
S. Prabagaran ◽  
T.S. Vishnu

Aluminium/graphite composites are the need of modern times for addressing the fuel saving issues. The graphite in such composites act as solid lubricant and it reduce external fuel requirements. But such composites are having degraded mechanical properties due to the graphite content in composite. In order to solve the negative effect of graphite on mechanical properties of LM13/Gr self-lubricating composite this study was conducted to find out the mechanical properties of LM13/B4C/Gr Metal Matrix Composites. Boron carbide was selected as reinforcement because of its better reinforcement properties compared to alumina and silicon carbide. The properties of the hybrid composites were compared with the LM13/Gr self-lubricating composite to study the enhancement in mechanical properties that has been caused by the boron carbide particles. Using computerized universal testing machine and rock-well hardness tester mechanical properties such as hardness and tensile strength were tested. Pin on disk testing machine was used to analyse the wear behavior. The test results indicates that by raising weight % of boron carbide particles in the LM13, tensile strength and hardness of the hybrid composites was increased compared to self-lubricating composite accompanied by better tribological properties.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sathiyamoorthy Margabandu ◽  
Senthil Kumar Subramaniam

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.


2016 ◽  
Vol 68 (2) ◽  
pp. 233-241 ◽  
Author(s):  
BM Viswanatha ◽  
M Prasanna Kumar ◽  
S Basavarajappa ◽  
TS Kiran

Purpose – This paper aims to investigate the microstructure, hardness and tribological properties of hypoeutectic (Al-7Si) matrix reinforced with fixed quantities of 3 Wt.% graphite (Gr) and x Wt.% SiCp (x = 3, 6 and 9) hybrid composites. Design/methodology/approach – The composites were fabricated by stir cast technique. The microstructure, hardness and tribological measurements were carried out on the base alloy and composites. The tribological investigation was carried out on pin-on-disc wear testing machine under dry sliding condition. Findings – The wear rate decreases with the increase of SiCp into A356-3Gr composites. The composite containing A356-9SiCp-3Gr had better hardness and good wear resistance compared to the base alloy. Scanning electron microscope (SEM) and electro dispersive spectrometry (EDS) images were used to study the reinforcement distribution and worn-out surface of the specimens. Originality/value – The present paper brings out a clear picture of the various events that take place under the worn-out surfaces leading to the generation of mechanical mixed layer.


2018 ◽  
Vol 15 (2) ◽  
pp. 312-320 ◽  
Author(s):  
Shanti Kiran Zade ◽  
Suresh Babu V. ◽  
Sai Srinadh K.V.

Purpose The purpose of this study is to manufacture test boards for re-enacting plant or field situations where vacuum chamber for expelling gas bubbles and autoclave equipment would not be accessible. This research focuses on the examination and enhancement of tensile strength for the nanocomposites consisting of uniaxial glass fiber mats, nanoclay (NC) and epoxy. Design/methodology/approach The parameters considered are the weight content of Cloisite 15A NC, the volume of glass fiber (Vgf) and the direction of glass fibers (θ). The composites are made by hand lay-up technique and tested according to ASTM D 638 standard. Taguchi L9 orthogonal array is used to design the experiments. Findings The results imply that the orientation of fibers exhibited high significance with a p-value of 0.001 for the upgrade of strength. NC percentage and the volume of fiber have a low effect as the p-values obtained were 0.375 and 0.294. Confirmation tests were performed at the optimal levels of parameters and the outcomes were in the permissible range of the anticipated values of S/N ratio and mean tensile strength. The negligible effect of nanoclay is due to the lack of infusion of resin into the d-spacing of clay layers due to the low configuration settings of mixing conditions which was confirmed by XRD studies. The negligible effect of glass fiber volume is due to the void content and lack of stress transfer between fibers uniformly due to the void content and improper mixing of nanoclay. Research limitations/implications The limitation of this study is that a low-speed mechanical stirrer was used to mix NC in the epoxy and the mixture was not subjected to vacuum and ultrasonication for degassing and deagglomeration. Practical implications These composites can be used as substitute materials in place of metallic parts in the aerospace and automobile sector. These composites can be used in civil structures instead of steel and concrete, which have low strength-to-weight ratio and where the requirement of strength is in the range of 60 to 390 MPa. Social implications The composites can be used in a variety of applications, for example, structural works, automotive panels and low-cost housing. Originality/value This research gives an idea about the combined contribution of NC, Vgf and “θ” to the improvement of tensile strength of the glass-epoxy composite.


2014 ◽  
Vol 592-594 ◽  
pp. 202-205
Author(s):  
V. Santhanam ◽  
M. Chandrasekaran ◽  
N. Venkateshwaran

Composite materials are widely used for their superior properties such as high strength to weight ratio, high tensile strength, low thermal expansion, low density etc. Due to environmental issues the eco-friendly composites are being explored. Natural fibers as reinforcement for polymer composites are widely studied. But natural fibers lack better mechanical properties when compared with synthetic fibers. Hence mixing the natural fiber with a synthetic fiber such as glass fiber will improve mechanical properties of the composites. In this study banana fiber is mixed with glass fiber, and the mixture is used as reinforcement in epoxy matrix. The composite specimens were prepared using hand layup technique, the fibers were randomly oriented. Further the fiber length was varied as 10, 15, 20 and 25mm and volume fraction as 10%, 15%, 20% and 25%. Experiments were conducted to find the effect of fiber length and volume fraction on tensile strength, flexural strength, water absorption properties of the composites. It is observed that a fiber length of 20mm and 20% fiber volume fraction gave better mechanical properties.


Author(s):  
A. A. Gorbatovskiy

The article presents results of strength tests of bismuth telluride prismatic samples obtained by growing crystals. These crystals have semiconductor properties and are used in the heat machines, the run-ability of which largely depends on the strength of crystals. Data available in the literature are significantly different from each other. It has been shown that, the most consistent strength tests results are obtained in case of bend testing. The measurement results of the elasticity modulus and tensile strength are given. For tests, an INSTRON testing machine with maximum direct stress of the 1000 H was used.


Author(s):  
L. V. Tashmatova ◽  
О. V. Mantseva ◽  
N. V. Gorbacheva

The basic moments of a process of obtaining apple tetraploids as donors of diploid gametes for apple breeding with polyploidy using are demonstrated. In industrial terms, triploids are of the greatest importance. The manifested effect of heterosis leads to the improvement of many characteristics - higher resistance to diseases, pests and adverse environmental conditions, greater autogamy than in diploids, less pronounced periodicity of fruiting, larger fruits and a convenient crown for harvesting. Triploids are developed as a result of crosses 2n × 3n or 2n × 4n. Tetraploids are necessary for more successful apple breeding with polyploidy using. For industry they are not of great importance but they are of interest as donors of diploid non-reduced gametes and allow to make the selection process more directional. One of the methods of experimental polyploidy is the induction of polyploids using mutagenes. The germs were treated with colchicines at concentrations 0.1% - 0.4% during 24 and 48 hours. According to the morphology the obtained plants were divided into five groups. Colchicine concentrations 0.3% and 0.4% during 48 hours of the treatment had a disastrous impact on the development of germs. As a result of the cytological analysis, tetraploids and chimeras were revealed, which were obtained from the seeds from the open pollination of Orlik and Svezhest (treatment variants – 0,1% colchicines solution and 24 and 48 hours of exposition), as well as from the seeds obtained as a result of the Svezhest × Bolotovskoye crossing. Tetraploids had a normal growth but they differed in large leaves, while chimeras were of low size with normal leaves and internodes.


2021 ◽  
Vol 55 (2) ◽  
pp. 331-349
Author(s):  
Hannes Orelma ◽  
Atsushi Tanaka ◽  
Maija Vuoriluoto ◽  
Alexey Khakalo ◽  
Antti Korpela

AbstractTraditional particle board can generate harmful indoor air emissions due to the volatile resin-based compounds present. This study investigated the preparation of sawdust particle board using the novel ionic liquid based fusion approach with [EMIM]OAc. The dissolution parameters were investigated using the thermal optical microscopy technique. The particle board sheets were prepared by hot pressing sawdust in the presence of ionic liquid (IL) ([EMIM]OAc) and subsequently purifying the fusion sawdust matrix from the IL with methanol. The fusion process of the sawdust particles was analysed with SEM and mechanical testing. The raw materials and the produced materials were investigated with elemental analysis, FTIR, and 13C-SS-NMR. IL fusion of the sawdust required a temperature above 150 °C, similar to the glass transition temperature (tg) of lignin. At lower temperatures, strong particle fusion was not obtained. It was observed that the sawdust/IL weight ratio was an important parameter of the fusion process, and a 1:3 weight ratio resulted in the strongest particle boards with a tensile strength of up to 10 MPa, similar to commercial particle boards. The particle fusion process was also studied with a twin-screw extruder. The extrusion enhanced the fusion of the sawdust particles by increasing dissolution of the sawdust particles, which was subsequently seen in elevated tensile strength (20 MPa). The study provides a practical view of how sawdust-based particle board can be manufactured using ionic liquid-based fusion.


2020 ◽  
Vol 17 (6) ◽  
pp. 831-836
Author(s):  
M. Vykunta Rao ◽  
Srinivasa Rao P. ◽  
B. Surendra Babu

Purpose Vibratory weld conditioning parameters have a great influence on the improvement of mechanical properties of weld connections. The purpose of this paper is to understand the influence of vibratory weld conditioning on the mechanical and microstructural characterization of aluminum 5052 alloy weldments. An attempt is made to understand the effect of the vibratory tungsten inert gas (TIG) welding process parameters on the hardness, ultimate tensile strength and microstructure of Al 5052-H32 alloy weldments. Design/methodology/approach Aluminum 5052 H32 specimens are welded at different combinations of vibromotor voltage inputs and time of vibrations. Voltage input is varied from 50 to 230 V at an interval of 10 V. At each voltage input to the vibromotor, there are three levels of time of vibration, i.e. 80, 90 and 100 s. The vibratory TIG-welded specimens are tested for their mechanical and microstructural properties. Findings The results indicate that the mechanical properties of aluminum alloy weld connections improved by increasing voltage input up to 160 V. Also, it has been observed that by increasing vibromotor voltage input beyond 160 V, mechanical properties were reduced significantly. It is also found that vibration time has less influence on the mechanical properties of weld connections. Improvement in hardness and ultimate tensile strength of vibratory welded joints is 16 and 14%, respectively, when compared without vibration, i.e. normal weld conditions. Average grain size is measured as per ASTM E 112–96. Average grain size is in the case of 0, 120, 160 and 230 is 20.709, 17.99, 16.57 and 20.8086 µm, respectively. Originality/value Novel vibratory TIG welded joints are prepared. Mechanical and micro-structural properties are tested.


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