Trends in Materials Engineering

In this study, a relation between reinforcement particles’ quantity variation and wear behaviour along with hardness properties of the aluminium-based functionally graded material (FGM) was established. Alumina particles were reinforced in aluminium-based functionally graded metal matrix composite, and the composites were manufactured by centrifugal casting at a constant speed. The matrix of the composite was a non commercial aluminium alloy, and Al₂O₃ particles, with an average grain size of 80 μm, were used as reinforcement. The reinforcement was varied in the range of 3.0–7.5 vol.%, and all the samples were prepared as per the ASTM standards. A pin-on-disc tribometer was used to study the sliding wear behaviour of composites. During the wear test, the speed of the disc was kept constant (0.5 m/s) and load was varied (20 and 25 N) at room temperature. The disc was made of AISI 52100 steel and acted as counter-body. In centrifugally cast metal matrix composite, the accumulation of alumina particles was found towards the outer region of the casting, which also showed an increase in the microhardness in that region. Wear testing indicated comparatively less wear towards the external zone of the castings.

FRPs are widely used composite materials, and they offer great advantages of reduction in weight compared to conventional materials. Delamination is seen as one of the biggest causes of its failure. The work herein examines fracture behavior pattern of GFRP laminates, made by reinforcing E-glass plain weave (PW) fiber and epoxy as matrix material. The Plain weaved fiber finds large acceptability in composite industries due to their flexibility, better handling capacity during manufacturing, and better damage tolerance. The laminate was configured in symmetric and asymmetric conditions and made by hand layup assisted by vacuum bagging technique. The laminates configured are quasi-isotropic with zero bending-extension stiffness coupling matrix. Mode-I test was conducted following ASTM D5528 standard in a computerized UTM in displacement control mode. The numerical analysis was done using cohesive zone modeling. The results showed better fracture toughness for asymmetric layup which was due to extensive fiber bridging in these kinds of layups. The numerical results were able to mimic the delamination behavior, and close similarity is obtained in force–displacement curve.

Electrical discharge machining is a flattering non-conventional material removal process which uses energy instead of tool to remove materials. This process has capability to machine virtually any electrical conductive and extremely hard metallic materials such as metal matrix composites, aluminum metal matrix composites, duplex steel, nickel, and titanium alloys. These materials are difficult to machine by conventional process because of high cost of tool, rapid tool wear, low materials removal rate which leads to formation of build-up edges, poor surface finish and burr formations. In order to machine these materials by electrical discharge machining, machining performance will be appropriate. Many researchers have suggested a lot of appropriate ways to improved machining of these materials by analyzing the process parameters of electrical discharge machining. These studies show that machining of these materials can be improved by proper selection of process parameters. This article shows the review of experimental and theoretical studies carried out so far in the field of electrical discharge machining. This article also explored the optimization techniques used to determine process parameters for EDMed aluminum metal matrix composites.

Use of bio-composites is gaining acceptance in the engineering world swiftly. However, materials wear out and erode with passage of time. Not much study, however, has been done on this aspect of bio-composites. In this paper, study of tribological behaviour of rice husk-reinforced composites has been done. The effect of rice husk addition has been observed on the wear characteristics of the composite using a pin-on-disc machine. It is seen that the increase in weight percentage of rice husk results in poorer wear characteristics. The SEM micrographs showed improper adhesion between the fibre and the matrix as the reason behind this deterioration in wear strength. Pre-treatment of rice husk with sodium hydroxide improves the adhesion between the matrix and the fibre which is evidently proven by the improvement in wear rate. The increase in wear strength is further corroborated by SEM photographs. It can be concluded that improving the adhesion between the fibre and the matrix by alkali treatment can enhance the working life of the material which can be beneficial in economic and environmental terms.

Tribological performance of carbon fiber reinforced epoxy polymer composites (CFRP) in dry and oil lubricating condition. The tests were conducted on a pin-on-disk machine under different applied loads and at a constant sliding velocity. CFRP composite laminates were manufactured by wet lay-up technique followed by vacuum bagging. All the samples were rubbed against a counter-surface of steel (En-31) having hardness of 60 HRC and average surface roughness (R_a) of 0.3 μm. Tribological performances in terms of wear and frictional characteristics were evaluated on the basis of total weight lost during experimentation and specific wear rate of the material and coefficient of friction, respectively. The experimental results show that maximum specific wear rate of CFRP composites with a value of 1.56 × 10⁻⁵ mm³/Nm and 2.77 × 10⁻⁵ mm³/Nm under oil lubricated and dry sliding condition, respectively. The eroded surfaces of CFRP coupons were characterized by Field Emission Scanning Electron Microscope (FESEM) to find out wear mechanism under dry and oil condition.

This paper evaluates the effect of fiber volume fraction and ply stacking sequence on the tensile and flexure strength of GFRP laminates. Six- and 8-plied laminates of equal thickness with two different ply stacking sequences (symmetric and asymmetric laminates) and different fiber volume fractions (v_f = 45 and 56%) were fabricated using press molding method. Flexural strength was evaluated under a 3-point bend test according to ASTM D790 and tensile test as per the ASTM D3039 testing standard. Results showed that the static mechanical properties of the laminates were a function of fiber volume fraction and fiber orientation. Samples with high v_f presented low tensile strength and high flexure strength compared to the specimen with lower v_f. While among symmetric and asymmetric stacking sequence, symmetric one independent of v_f had better tensile and flexure properties.

In this experimental study, the effect of span-to-depth ratio on flexural properties of woven glass fiber symmetric laminates was investigated. Two span-to-depth ratios of 15:1 and 30:1 were selected to assess the effect of span length on the flexure properties of woven GFRP laminates. Five samples from each span-to-depth ratio were tested according to the ASTM D790-17 standard under 3-point bending mode on Hounsfield H50KS, a computer-controlled universal testing machine. Tests revealed that flexure strength of woven GFRP laminates depends upon its span length. However, flexure strain to failure remained almost in the similar range for the specimen with different span lengths. Average flexural strength and modulus of samples with 15:1 and 30:1 span-to-depth ratio were obtained as 160.56 MPa, 14.99 GPa and 139.06 MPa, 19.17 GPa, respectively. Similarly, average strains to failure in the samples were found to be 0.01215 and 0.00853% in the respective order.

Using a desiccant-based dryer, the drying chamber is tested in the heat transfer laboratory, Faculty of Engineering, Dayalbagh educational institute, Agra. Experiments are carried out to analyze the effect of heat on the drying maize at a different time and different drying trays positions. After harvesting, drying is an indispensable process for extraction of moisture content of grain production and improving overall performance for better outcomes. In India, sun drying is the main drying method used by farmers for drying their crop grain yield. The desiccant dryer is used for dehumidification of maize to remove moisture contents. The present research work emphasizes to analyze dehumidification on maize in the drying chamber at different time interval by using a thermal camera. A thermal camera is used to find the drying rate and performance evaluation of maize. Performance of dehumidifier is also correlated with the heat parameters. Thermal imaging gives a realistic and deeper view of grain drying. The efficiency was calculated to be 76.45% using desiccant drying.

This paper investigates the low-velocity impact response of a glass fiber-reinforced polymer (GFRP) composite. A four-layered anisotropic bidirectional glass fiber composite laminate is modeled using HyperMesh. The thickness of each ply is considered as 0.5 mm, and the radius of the impactor is 10 mm. The oblique angle impact at 0°, 15°, 30°, and 45° (inclination of laminates with the horizontal plane) is simulated using LS-DYNA, which is a 3D commercially available software. A comparative study is carried out for energy absorption, stress generation, damage caused, and deflection of the laminate at 3 m/s impact velocity. The results of the mechanical testing simulations justified that the impact angle highly influences the impact response. Therefore, it may help in designing mechanical components that are exposed to oblique low-velocity impact (LVI) situations.

FRP laminates are highly vulnerable to low-velocity impact (LVI) because it induces barely visible impact damage (BVID) inside the structure. This kind of fracture or damages is dangerous to the structure because these damages may go unnoticed ultimately leading to sudden and catastrophic failure of the structure. In this numerical simulation LVI is carried out using LS-DYNA on GFRP laminate impacted by a hemispherical striker of diameter 10 mm. Since in real-life situations structures may not be always constrained from all sides thus in this work behavior of GFRP laminate is examined when one edge (long or short) and opposite edge (long or short) of the laminate are constrained which resemble that of the cantilever and fixed type of beams, respectively. From results, it is observed that GFRP laminate under one short edge-constrained boundary condition showed 31.8% added deflection than one long edge-constrained boundary condition but one long edge boundary condition absorbed more energy than one short edge-constrained boundary condition. In case of two edge-constrained boundary conditions, two short edge-constrained boundary conditions showed partial deflection and partial penetration of the impactor while complete penetration of the striker is observed for two long edge-constrained boundary conditions without any deflection and it absorbed more energy by undergoing damage than two short edge-constrained boundary conditions.

The function of non-covalent interactions in structure–property relationship of [ZnX₄]²⁻-based inorganic–organic hybrid materials has been studied in a series of compounds which were examined and determined with XRD data. The XRD data have been used for computer-generated structural model through computational systems to compute the non-covalent bonds in order in ZnCl₄, ZnBr₄, ZnI₄, and ZnF₄ hybrids. The molecular structures have revealed that organic materials are held inside the inorganic components through non-covalent interactions by hydrogen donor-to-acceptor, hydrogen donor to ring centroid, within the halide groups and also within the metal–metal atoms of the compound to form the different structural motifs. The selected materials were analyzed for the predominance of the hyper-Raman and Infrared spectra modes of [ZnCl₄]²⁻ hybrids in comparison with the [ZnBr₄]²⁻, [ZnI₄]²⁻[ZnF₄]²⁻, etc. types of hybrid derivatives are calculated through the fractional coordinates obtained from the structural data. These spectroscopic parameters indicate that such hybrid materials have optical properties.

The application of synthetic fibres in polymer composites is deteriorating because they are costly and detrimental to climate. The abundant availability of natural fibres and manufacturing ease have prompted researchers to try locally accessible natural fibres and to study their viability of reinforcement purposes and to examine their suitability as a reinforcement alternative for polymer composite. The economics and the high specific mechanical properties validate natural fibre to be a good renewable and biodegradable alternative to the synthetic reinforcement, i.e. glass fibre. Incorporation of natural fibres into the polymer is currently a standard innovation to enhance the mechanical properties of polymer. One of the biggest areas of recent development in natural fibre plastic composites worldwide is the automobile industry, where natural fibres are profitably utilized because of their low density and ever expanding climatic concerns. In this research work, the composites were synthesized using wheat husk particles as filler and polystyrene as the matrix material. Mechanical properties are studied for different filler sizes, i.e. 250–355, 355–500 and 500–710 µm and at different filler loadings, i.e. 5, 10 and 15%. Tensile strength, flexural strength, hardness and wear properties were investigated, and it was concluded that the best mechanical properties are obtained at 15% filler loading and smallest filler size studied, i.e. 250–355 µm except in case of wear rate of the composites.

A6082-ZrO₂-SiC hybrid metal matrix composite successfully fabricated by the combined stir and squeeze casting method. The fine grain structure is observed in the optical microstructure of base alloy and hybrid composites. SEM images of A6082 with 1 wt% of SiC and 1 wt% ZrO₂ composites observed with uniform distribution of reinforcement particles. Hardness 18.6% increase in hybrid composite reinforced with 1 wt% ZrO₂ compared to the base alloy. Izod impact strength 18% increased with 1 wt% addition of ZrO₂ compared to the base alloy. Compression strength increased up to 20% in A6082 reinforced with 1 wt% ZrO₂ and SiC 1 wt%.

The parameters which effect die sinker electric discharge machine’s material removal rate are studied over here. The material focused in this experimental study is beryllium copper alloy C-17200, and electrode/tool used for machining is made of mixture of graphite and brass on EDM model EDM4025. Material removal rate is calculated and analyzed for selected set of machining parameters. The thermal analysis plays an important role in analyzing and solving the EDM of Be–Cu in terms of heat distribution. A thermal model using simulation software ANSYS is presented in order to distinguish the influence of factors current and pulse on time in EDM process of heat circulation beside the depth and radius of machining workpiece. As beryllium copper alloy (C-17200) has many applications and because of properties that is strong oxidization resistance, high hardness and elevated wear resistance Be-Cu has extensively used in industrial application such as in dies and cutting tools, automotive and aerospace industries.