Browsing by Author "Sahu, R.K."

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Artificial Intelligence System Approach for Optimization of Drilling Parameters of Glass-Carbon Fiber/Polymer Composites
(Springer Science and Business Media B.V., 2021) Upputuri, U.H.; Vijaya Sai, N.V.; Sahu, R.K.
In recent times, the study on machining characteristics of combined (hybrid) fiber polymer composites has drawn a remarkable research attention because of its emerging industrial applications. The present study focuses on the drilling of hybrid glass-carbon fiber reinforced (GCFR) epoxy composites fabricated using hand layup technique. The machining characteristics were considered in the drilling of GCFR composites which include thrust force, torque, delamination factor and surface roughness. The influence of the drilling process parameters such as spindle speed, drill diameter and feed rate on the characteristics are studied. To avoid the confounding effect of the individual optimized characteristics, an artificial intelligence system i.e. fuzzy inference system approach is adopted. The fuzzy inference system transformed all the performance characteristics of drilled hybrid composites into a multi response performance index (MPI) and optimized the MPI at the common factor level setting. The optimal combination of process parameters for minimum thrust force, torque, delamination factor and surface roughness found to be: speed 3000 RPM, drill diameter 5 mm and the feed rate 50 mm/min. The analysis of variance results show that drill diameter is the most significant parameter followed by feed rate and speed. Further, a theoretical model was proposed for the estimation of MPI and found that an average absolute error of 14.8% with respect to the experimental MPI data is obtained. © 2020, Springer Nature B.V.
Characterization of Inconel 625-SS 304 Weldments Developed by Selective Microwave Hybrid Joining Technique for Promising Applications
(Springer, 2024) Kamble, D.L.; Sahu, R.K.; Narendranath, S.
Production of dissimilar weldments using microwave hybrid heating is currently gaining immense impetus in the field of advanced welding. This is because such heat source could provide benefits like cost-effectiveness, rapid, volumetric, uniform and selective heating, and efficient throughput which would be significant to various industries. Till-date researchers have carried out joining of dissimilar general purpose engineering materials using microwave hybrid heat source. But attention has not been paid on the joining and characterization of dissimilar exotic-general purpose materials using the aforementioned heat source and the promising applications of the weldments. Therefore, the present article is focused on the joining of dissimilar materials- Inconel 625 and SS 304 alloys using selective microwave hybrid joining (SMHJ) technique. In SMHJ, nickel-based powder is used as a filler material, Silicon carbide (SiC) block and SiC powder are used as susceptor to increase the initial temperature. The developed weldments through SMHJ are characterized using various physico-chemical diagnostic methods. The results reveal the average micro-hardness of joint was found to be 303 ± 17 HV owing to the presence of various carbides and nitrides phase like NbC, Cr23C6, Cr2Ni3, Ni8Nb, and Fe3Ni2 in the joint zone which is evident from XRD. The average UTS of the joints found to be 448.6 MPa with an elongation of 10.93% and flexural strength observed to be 435 MPa. Further, fractography study reveals, the joint regions have mixed mode of failure. The failure was attributed to the existence of secondary phases in the joint zone. © ASM International 2023.
Comprehensive Characterization of Novel Jute Fabrics with Musa Paradisiaca Leaf Agro-Waste Based Micro Cellulosic Fillers Reinforced Epoxy Composites For Lightweight Applications
(Korean Fiber Society, 2025) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.
For lightweight, sustainable, high-strength products, hybrid bio-epoxy composites materials were the most excellent choice for the production industry. The investigation proceeds in developing a four-stacked sequence jute-woven mats reinforced with epoxy composite and added with micro-cellulose fillers. The extraction of micro cellulose from Musa paradisiaca plant leaf (MPPL) was carried out through a series of processes, including alkali treatment, acid hydrolysis, bleaching, and slow pyrolysis. The composite was fabricated using the conventional hand lay-up method and compression molding. The microcellulose was added to the stacked composite at varying weight percentages (0, 2.5, 5, 7.5, and 10%). Thermo-mechanical and water intake characterization were investigated using ASTM. The findings revealed that incorporating 5% MPPL cellulose into the jute-stacked layer sequence resulted in improved hardness (95 HRRW), tensile modulus (3407.69 MPa), tensile strength (79.74 MPa), flexural modulus (2195.752 MPa), flexural strength (56.87 MPa), and crystallinity index (72.7%). However, a reduction in impact strength (23.27 kJ/m2) was noted compared to the unfilled composite. The higher thermal degradation (480 °C) behavior of the filler-reinforced composite makes them a suitable material for applications in high-temperature environments. Fractographical morphology was also investigated to reveal the bonding behavior, voids formations, agglomeration of fillers, and fracture behavior. Thus, this distinguishable composite characterization will aid the manufacturing industries in producing high-strength biodegradable materials. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.
DDoS Attack Detection onÂ IoT Devices Using Machine Learning Techniques
(Springer Science and Business Media Deutschland GmbH, 2022) Kumar, S.; Sahu, R.K.; Rudra, B.
The Internet of Things made life easy and simple. It has become a part of life to control the devices and activate them for various applications using the Internet. Due to the drastic increase of its usage in day-to-day life, researchers are moving towards the concept of everything connected to the internet which can lead to penetration. To avoid malicious penetrations into the network, it is required to develop a reliable mechanism for secure communication over IoT devices. In order to find the best accurate algorithm, many Machine Learning (ML), as well as Deep Learning (DL) methods, need to be applied to the collected dataset for the detection of DDoS attacks. Hence in this paper, an effective model is selected by applying and comparing all the ML and DL models on a dataset. Â© 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Effect of blending duration on physical, mechanical and tribological behavior of aluminum matrix composites: An experimental analysis
(Elsevier Ltd, 2024) Veeranaath, V.; Sahu, R.K.; Priya, I.M.
Aluminum matrix composites exhibit a vibrant role in the present research and scientific world due to their astonishing features compared to other conventional materials. Among the various techniques available for processing these composites, powder metallurgy (P/M) is considered one of the prominent techniques. This is because of its identical dispersal of the fillers, near net shape samples, etc. wherein blending is the most imperative step of the process. To accomplish efficient blending of the phases for composite preparation, ball milling is found to be suitable. In this paper, aluminum matrix composites filled with 20 wt% novel reinforcement (extracted from Aegle marmelos) is synthesized via the P/M technique by varying the blending duration from 60 to 240 min to study its effect on the behavior of composites. The mixing of the constituents is carried out at 300 rpm with a ball-to-powder ratio of 10:1 in ball milling. The blended powders were then compacted and sintered in an inert gas atmosphere for consolidation. The hardness, density, and wear tests were conducted to characterize the developed composite specimens. The microstructural characterization was carried out using an optical microscope and SEM, and the elemental composition of the synthesized composite was studied using EDS techniques. The hardness and density were found to have a growing influence up to a ball milling duration of 180 min and beyond this time there is found to be a decrement in the characteristics of the composites. This is due to the damage of the reinforcements observed during lengthier ball milling duration. The wear behavior of the fabricated specimens followed the same trend. Further, grey relational analysis was adopted in this study to determine the degree of relationship between the blending duration and the composites' behavioral performance. Â© Â© 2024 Elsevier Ltd. All rights reserved.
Exemplary approach using tool rotation-assisted µ-ECDM for CFRP composites machining
(Taylor and Francis Ltd., 2023) Bhargav, K.V.J.; Balaji, P.S.; Sahu, R.K.; Katiyar, J.K.
Carbon fiber-reinforced polymer (CFRP) composites are an advanced composite material class due to their remarkable properties such as high load-carrying capacity and low density. CFRP composites have enormous applications in aerospace, biomedical, automobile, etc. Machining the CFRP composite is need of the day, but issues like delamination, fiber pullouts, workpiece damage, etc. have made it difficult. These limitations can be surpassed by the micro-electrochemical corona discharge machining (µ-ECDM) process. Although the process has showcased high process capability and great versatility in machining conducting and non-conducting materials, the process has limitations in machining holes deeper than 300 µm because of insufficient electrolyte supply at the machining zone. Aiding assistance to the process can overcome the limitation by enhancing electrolyte availability. Therefore, an experimental analysis is carried out by generating through holes on the CFRP composite using a tailor-made rotating tool-assisted micro-electrochemical corona discharge machining (RT-µ-ECDM) system. The process parameters, voltage, concentration, duty factor, and tool rotation rate are taken at three levels. The materials removal rate and overcut as machining characteristics were analyzed. The multi-response optimization using JAYA algorithm and R-method is used to obtain the optimal process parameters. The experimental investigation suggests RT-µ-ECDM system can machine through holes on CFRP composite. © 2022 Taylor & Francis.
Experimental and computational studies on characteristics of indigenously produced novel Aegle marmelos micro polymer reinforced aluminum composites using powder metallurgy
(Korean Society of Mechanical Engineers, 2025) Veeranaath, V.; Sahu, R.K.; Priya, I.M.
In recent times, the quest for an advanced composite material (polymer reinforcement in metal matrix) has become a challenge for promising industrial and household applications. Therefore, the present study focuses on the indigenous production of a novel microparticle-based Aegle marmelos natural polymer reinforced (AMNPR) aluminum composites using the powder metallurgy (P/M) technique. The results revealed that the reinforcement (AMNP) concentration had a considerable effect on the physico-mechanical, thermal, and chemical characteristics of composites. Further, in this study, TOPSIS coupled with the CRITIC method (CRITIC-TOPSIS) is adopted to convert the multiple characteristics into a closeness coefficient (Ci) response. The optimal parameters are found to be reinforcement - 20 wt. %, ball milling duration - 180 min, and speed - 300 rpm. Moreover, the Ci values predicted by the artificial neural network (ANN) model are in good agreement with the experimental values having a mean absolute error of 4.116 %. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Experimental and Digimat-FE based representative volume element analysis of exceptional graphene flakes/aluminium alloy nanocomposite characteristics
(2019) Nayak, B.; Sahu, R.K.
The present article is focused on the in-house synthesis of graphene nano-flakes (size range: 3-8 nm) reinforced Al-alloy (AA6005 series) nanocomposites using stir casting process. The microstructure of the obtained Al nanocomposites at different concentration of flake shaped graphene nanoparticles (GRNPs) show that the particles at 2 wt% and 4 wt% found to be distributed extensively on the surfaces of Al alloy matrix but observed negligible across the grain boundary whereas in the case of 6 wt% concentrated developed composite specimen, the GRNPs were observed to be well dispersed both on the surfaces and grain boundary of the matrix. With the addition of the particles, there found to be the formation of more voids in the nanocomposite specimens. The experimental characterization results reveal that with the increase in graphene content to 6 wt%, the tensile strength, compressive strength, impact energy, hardness and wear resistance of the nanocomposites were increased by 9% to 36%, 30% to 44%, 9.8 J, 36.03 HRB and 33% respectively as compared to unreinforced alloy. It was observed that the composites with increased concentration of reinforcement exhibits brittle behaviour and at 6 wt% GRNPs, the elongation is almost found to be 50% lower than the unreinforced one. Further, a 3D microstructure representative volume element (RVE) model of aluminium nanocomposite is generated using Digimat-FE software. Then, microstructural deformation behaviour of the nanocomposite is realized by RVE model. The simulation results reveal that the tensile property of the aluminium nanocomposites predicted using RVE model is in well agreement with the experimental values. 2019 IOP Publishing Ltd.
Experimental and Digimat-FE based representative volume element analysis of exceptional graphene flakes/aluminium alloy nanocomposite characteristics
(Institute of Physics Publishing helen.craven@iop.org, 2019) Nayak, B.; Sahu, R.K.
The present article is focused on the in-house synthesis of graphene nano-flakes (size range: 3-8 nm) reinforced Al-alloy (AA6005 series) nanocomposites using stir casting process. The microstructure of the obtained Al nanocomposites at different concentration of flake shaped graphene nanoparticles (GRNPs) show that the particles at 2 wt% and 4 wt% found to be distributed extensively on the surfaces of Al alloy matrix but observed negligible across the grain boundary whereas in the case of 6 wt% concentrated developed composite specimen, the GRNPs were observed to be well dispersed both on the surfaces and grain boundary of the matrix. With the addition of the particles, there found to be the formation of more voids in the nanocomposite specimens. The experimental characterization results reveal that with the increase in graphene content to 6 wt%, the tensile strength, compressive strength, impact energy, hardness and wear resistance of the nanocomposites were increased by 9% to 36%, 30% to 44%, 9.8 J, 36.03 HRB and 33% respectively as compared to unreinforced alloy. It was observed that the composites with increased concentration of reinforcement exhibits brittle behaviour and at 6 wt% GRNPs, the elongation is almost found to be 50% lower than the unreinforced one. Further, a 3D microstructure representative volume element (RVE) model of aluminium nanocomposite is generated using Digimat-FE software. Then, microstructural deformation behaviour of the nanocomposite is realized by RVE model. The simulation results reveal that the tensile property of the aluminium nanocomposites predicted using RVE model is in well agreement with the experimental values. © 2019 IOP Publishing Ltd.
Experimental investigation on machining characteristics of titanium processed using electrolyte sonicated µ-ECDM system
(Nature Research, 2022) Bhargav, K.V.J.; Balaji, P.S.; Sahu, R.K.; Moussa, M.
Micromachining of difficult-to-machine materials is of prime focus nowadays. One such material is Titanium, which has numerous applications in aerospace, chemical, and biomedical industries. The micromachining of Titanium has become the need of the day because of its exhilarating properties. This investigation employs a tailor-made electrolyte sonicated micro-electrochemical discharge machining (ES-µ-ECDM) system to generate microholes in a commercially pure titanium plate with a thickness of 1000 µm. The machining chamber is the ultrasonication unit (36 kHz) with process parameters voltage (V), concentration (wt%), and duty factor (DF) chosen at three levels. The FCC-RSM-based DOE is selected for experimentation to study the machining characteristics like material removal rate, overcut, and circularity. Through holes were achieved at parameters of 80 V, 25 wt%, and 60% DF and 80 V, 30 wt%, and 50% DF. The incorporation of ultrasonication into the system enhanced electrolyte replenishment and evacuation of the debris at the machining vicinity. The assistance technique improved the gas film stabilization around the tool enabling uniform machining. The multi-response optimization is performed using the MOJAYA algorithm to obtain Pareto optimal solutions, and the MADM (R-method) is employed to obtain the optimal parameter. The optimal parameter was found to be 69 V, 30 wt%, and 50% DF, at which the machined microhole was found to have a circularity of 0.9615 with minimal surface defects. © 2022, The Author(s).
Generation of microchannels on PMMA using an in-house fabricated μ-ECDM system
(Walter de Gruyter GmbH, 2023) Bhargav, K.V.J.; Balaji, P.S.; Sahu, R.K.
Electrochemical corona discharge micromachining (μ-ECDM) is a newly advented, advanced hybrid machining process capable of machining non-conducting and conducting materials. In this article, Polymethyl methacrylate (PMMA), a non-conducting material, often used in microfluidic applications, is machined to generate microchannels. The process parameters chosen for machining are voltage, duty factor, and concentration. The process parameters are chosen at three levels, and their effect on machining characteristics such as material removal rate and surface roughness are detailed in this paper. Optimization is carried out for individual response using the signal to noise ratio optimization technique for maximizing material removal rate and minimizing surface roughness. © 2023 Walter de Gruyter GmbH, Berlin/Boston.
Generation of microholes on GFRP composite using ES-µ-ECDM system
(Elsevier Ltd, 2022) Bhargav, K.V.J.; Shanthan, P.; Balaji, P.S.; Sahu, R.K.; Sahoo, S.K.
Microfeatures fabrication on FRPs is very essential nowadays because of its growing demand in various industries like aerospace, automobile, space, marine, etc. Glass fiber reinforced plastic (GFRP) composite is one among the FRPs that has many potential applications with extraordinary physical, chemical and mechanical properties. Generation of microholes on GFRP composite has gained its pace in recent years because of its applications in circuit boards and filters in biomedical applications. This study focuses on the generation of microholes in GFRP composite using an in-house developed electrolyte-sonicated micro-electrochemical discharge machining (ES-µ-ECDM) system. The process parameters voltage (V), concentration (wt%), and feed rate (µm/s) are selected at three levels for performing experiments using FCC-RSM modeling. The machining responses material removal rate (MRR) and overcut (OC) are analyzed. A RSM-based regression model is developed, and a multi-objective optimization using the MOJAYA algorithm is employed to obtain a set of non-dominated Pareto optimal solutions. The Pareto optimal solution set showed a feed rate of 5 µm/s should be employed for better MRR and OC. The SEM micrographs have shown a feed rate of 5 µm/s produced smooth surfaces at voltages and concentrations less than 55 V and 17.5 wt%, respectively. © 2022 Elsevier Ltd
Influence of In-house Synthesized Micro-Aegle Marmelos Polymer Concentration on Physico-Mechanical Properties of Aluminum-Based Composites
(Springer Nature, 2025) Veeranaath, V.; Sahu, R.K.; Priya, I.M.
For lightweight applications such as aircraft, automotive components, household, and infrastructure applications, using natural polymer fillers as reinforcement in aluminum metal matrix composites (MMCs) instead of metallic and ceramic fillers could be an attractive candidate. Therefore, the present work newly investigated the synthesis of Aegle Marmelos polymer powders (AMP) via a chemical route, followed by the fabrication of AMP-reinforced aluminum MMCs by the powder metallurgy (P/M) technique. The AMP concentration is increased in increments of 5% by weight up to 35%. The SEM results showed that the fillers are homogeneously distributed in the matrix and the bonding between them is improved. The mechanical characterization results showed that at an AMP concentration of 20 wt%, the density, hardness, and tensile strength were increased by 13%, 6.35%, and 44%, respectively, compared to the base material. In addition, a wear test is performed on the synthesized composites and the responses such as coefficient of friction and specific wear rate are individually optimized using the Taguchi approach. The common optimal parameters for the minimum coefficient of friction (0.3832) and the specific wear rate (7.83 × 10?5 mm3/Nm) are 20 wt% AMP reinforcement, sliding load 20 N, disk speed 550 rpm, and sliding time 5 min. The results of the confirmatory wear test showed that the difference between Taguchi's predicted and experimental response values ??is less than 9%. Analysis of variance results also showed that AMP reinforcement is the most significant parameter. Overall, Al-20 wt% AMP composites exhibited improved physico-mechanical properties for promising applications. © King Fahd University of Petroleum & Minerals 2024.
Influence of Microwave Power and EWAC-1004EN Filler Size on Characteristics of Inconel 625 and SS 304 Weldments Produced Using Microwave Irradiation Hybrid Joining System
(Springer Nature, 2025) Kamble, D.L.; Sahu, R.K.; S, N.; Badiger, R.I.
The present study focuses on welding of Inconel 625 (exotic) and SS 304 (general purpose) dissimilar alloys using the microwave irradiation hybrid joining system and subsequent characterization of the joint processed through microwave energy. The process parameters, namely microwave power (4.4 kW and 2.2 kW) and interfacial powder EWAC 1004 EN (average particle size: 75 µm and 25 µm) are employed. The individual influence of process parameters on weldment properties is studied. The joint specimens developed at 2.2 kW power show the enhancement of ultimate tensile strength (UTS), flexural strength (FS), and average microhardness by 33.44%, 71.42% and 31.25%, respectively, in contrast to their counterparts developed at 4.4 kW keeping particle size constant. Similarly, the UTS, FS and average microhardness of the specimens developed using EWAC-1004EN powder of average particle size (APS) 25 µm found to considerably increased by 76.07%, 32.06% and 55.55%, respectively, as compared to the joints developed using 75 µm APS with constant microwave power. This enhancement in the mechanical properties is attributed to the formation of different carbide and intermetallic phases such as NbC, Cr23C6, Cr2Ni3, Ni8Nb, and FeNi in the weld region which is evident from XRD. Furthermore, the fractured specimens obtained from tensile and flexural tests are examined using FESEM. It is observed that both ductile as well as brittle fracture occurred. This mixed fracture is particularly ascribed to the presence of secondary/ intermetallic phases in the fusion region. © King Fahd University of Petroleum & Minerals 2025.
Influence of Process Parameters and its Optimization on Wear Behavior of an Exceptional Aegle Marmelos Polymer/Aluminum Composite
(Springer, 2024) Veeranaath, V.; Sahu, R.K.; Priya, I.M.
The present paper is focused on the indigenous production of a unique and low-cost Aegle Marmelos natural polymer (AMNP) powder via chemical synthesis and its reinforcement in the aluminum matrix via powder metallurgy. The wear behavior of Aegle Marmelos natural polymer-reinforced (AMNPR) aluminum composites is studied. The effect of control parameters like reinforcement (wt.%) and different sliding parameters on the wear characteristics is discussed. The SEM studies revealed that severe damage due to adhesive wear, delamination, and formation of oxide zones is observed at reinforcement concentrations of 10 wt.% and 15 wt.%. The optical profilometry study also revealed that the roughness of the worn-out samples was maximum at 10 wt.% reinforcement. Further, the process parameters with each characteristic are optimized individually and the optimal parameters are different. To avoid this confounding effect, TOPSIS coupled with CRITIC method is adopted to convert all characteristics into a closeness coefficient (Ci) and optimize at a common parameter level setting. The optimal combination of process parameters for minimum wear characteristics is as follows: reinforcement concentration: 20 wt.%, sliding load: 25 N, sliding speed: 200 rpm, and sliding duration: 4 min. The confirmation test results were validated and showed an improvement of the closeness coefficient by 0.0116. In this study, a statistical multi-regression model is also developed for predicting the closeness coefficient of the developed composites under different parametric conditions. The predicted values obtained from the regression model agreed well with the experimental values, with a mean absolute error of 5.478%. © ASM International 2024.
Isolation of microcrystalline cellulose from Musa paradisiaca (banana) plant leaves: physicochemical, thermal, morphological, and mechanical characterization for lightweight polymer composite applications
(Springer Science and Business Media B.V., 2024) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.
Natural cellulose owing to its remarkable microstructural and physiochemical behaviour, and its eco-friendliness have attracted significant interest among the researchers. Therefore, in this work, microcrystalline cellulose (MCC) is extracted from the Musa paradisiaca plant leaf (MPPL) debris which is accumulated in large quantity and treated as waste material. The purified micro-cellulose is obtained by subjecting the MPPL raw material to alkali treatment followed by acid hydrolysis, bleaching and slow pyrolysis. From the FT-IR spectra of the cleaned cellulose, it is observed that its amorphous phase is eliminated. The crystallinity index is found to be 87.42% and this value is attributed to the sodium chlorite bleaching. The particle size analyzer results show that the micro-cellulose found to have a bimodal distribution with an average size of 35.97 μm and standard deviation 16.53. It is evident from SEM that the microcrystalline cellulose is of semi-spherical in shape and found to be aggregated with uneven distribution. Further, TGA analysis is carried out in this work and the results show that the microcrystalline cellulose can exhibit high heat resistance up to 297 °C. Surface roughness values (Ra) for MPPL MCC is 58.41 μm. The properties are well suited for futuristic polymer composite applications such as filler addition in biofilm for packaging industries and coating material in pharma industries. © The Polymer Society, Taipei 2024.
Jute/basalt fabrics in microcellulosic-filled epoxy composites for lightweight applications
(Elsevier Ltd, 2024) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.; Kalidindi, K.S.
For the production of lightweight, eco-friendly, and incredibly robust products, hybrid bio-epoxy composites stand out as an outstanding material choice in the manufacturing sector. This study focused on creating a composite, where in the epoxy resin infused with microcellulose fillers is reinforced by stacking four layers of basalt-jute-jute-basalt woven mats. The composite was made through the hand lay-up process, followed by the meticulous process of compression molding. The inclusion of microcellulose, sourced from the leaves of the Musa paradisiaca plant (MPPL), was a key component. The extraction of microcellulose from the MPPL involves alkali treatment, acid hydrolysis, bleaching, and slow pyrolysis. This micro cellulose was introduced to the layered composite in varying proportions (ranging from 0 % to 10 %). Subsequently, we carried out comprehensive tests in line with ASTM standards to assess the material's effectiveness with regard to thermo-mechanical properties and water absorption characteristics. The outcomes of these evaluations highlighted that the composite featuring a 5 % Musa paradisiaca plant leaf micro cellulose content within the basalt-jute-jute-basalt layers exhibited notably superior attributes in tensile strength (99.74 MPa), flexural strength (77.87 MPa), impact strength (40.27 kJ/m2), hardness (97 HRRW), and crystallinity index of 6.3 %. Furthermore, our investigation extended to the analysis of fractural morphology to understand the bonding behaviour and fracture patterns within the composite. © 2024 Elsevier B.V.
Machining Parameter Optimization of Wire Electrical Discharge Machining for Ni50.3Ti29.7Hf20 Alloy Using TOPSIS and Grey Wolf Optimization Technique
(Springer, 2025) Bhaskar, M.; Balaji, V.; Narendranath, S.; Sahu, R.K.
Ni50.3Ti29.7Hf20 is an alloy with shape memory characteristics that can withstand high temperatures. It possesses remarkable strength, hardness, and exceptional corrosion resistance. SMAs are well-suited for various applications, including automotive sensors, automobiles, aerospace technologies, robotics, actuators, and MEMS devices. However, its unique properties make it difficult to machine using conventional methods. Wire EDM is an unconventional machining process suited for difficult-to-machine materials like Ni-Ti-Hf alloy, providing high accuracy and precision and minimizing the risk of material damage. This paper focuses on the optimization of machining parameters, namely Discharge time (PON), Pause time (POFF), Gap voltage (GV), and Wire travel speed (WS) during WEDM of Ni-Ti-Hf shape memory alloy utilizing the TOPSIS and GWO techniques. The aim is to obtain optimal machining parameters for improving the machined Ni-Ti-Hf alloy’s material removal rate (MRR) and surface roughness (Ra). The optimal machining parameters from GWO were PON = 123.8 µs, POFF = 50 µs, WS = 2, and GV = 25. The predicted values of material removal rate and surface roughness are 4.22 mm3/min and 3.62 µm, respectively. The experimental verification demonstrates the proposed optimization approach's effectiveness, as the predicted values correlate strongly with the actual values. © ASM International 2023.
Mechanical properties of MWCNTs and graphene nanoparticles modified glass fibre-reinforced polymer nanocomposite
(Springer, 2021) Seshaiah, S.; Reddy, K.V.K.; Sahu, R.K.; Katiyar, J.K.
In the present study, the multi-walled carbon nanotubes (MWCNTs) and graphene nanoparticles were used as a reinforcement to fabricate glass fibre polymer composite at different orientations (unidirectional glass fibres 0° and 90°; woven glass fibres 0°/90° and 45°/45°). The composites were developed using hand lay-up-assisted vacuum bagging method at 1 torr pressure. The concentrations of nanoparticles (~diameter 5–20 nm) were varied in the range of 0.1–0.3 wt% in the matrix. The mechanical properties like impact strength, tensile strength and fatigue strength were carried out on Izod and Charpy machine, universal testing machine and computer-controlled machine under sinusoidal wave, respectively. It is observed that the glass fibre/epoxy composite blended with MWCNTs/graphene by 0.2 wt% has shown higher fatigue life by 56%, higher tensile strength by 36% and higher capability of energy absorption by 927.7% in notched type and lower capability of energy absorption by 155.43% in un-notched type, as compared to pure composite. The increment in properties is due to the better bonding between fillers and matrix. However, the increase of MWCNTs and graphene nanoparticles by wt% in composite laminates have shown lower fatigue strength because of the agglomeration of MWCNTs particles in matrix that caused the propagation of fatigue cracks under cyclic loading. Further, the damage behaviour of composite materials was analysed using scanning electron microscopy. It is found that a different damage behaviour in each composite is observed which is attributed to the matrix cracking, fibre rupture, fibre pullout, fibre split and fibre de-bonding. © 2021, Indian Academy of Sciences.
Micromachining of Al7075 alloy using an in-situ ultrasonicated µ-ECDM system
(Taylor and Francis Ltd., 2023) Bhargav, K.V.J.; Pyla, K.R.; Balaji, P.S.; Sahu, R.K.
Al7075 is a lightweight metal alloy essentially used in various engineering sectors possessing applications in aerospace, military, missile, etc. Miniaturized machining operations have placed a great deal of pressure on the conventional machining capabilities of Al7075 alloys as they possess certain challenges due to their ductile and unique adhesive nature, which must be overcome. The present study focuses on generating through-holes on Al7075 alloy using an electrolyte ultrasonication-assisted µ-ECDM system. The FCC-RSM factorial-based design is chosen at three levels to carry out experimentation with process characteristics voltage (V), concentration (wt%), and duty factor (%DF). The material removal rate (MRR), top hole overcut (TOC), bottom hole overcut (BOC), and circularity (CIR) are the machining responses. JAYA algorithm, a multi-objective optimization is performed, and optimal process parameters are obtained using the R method. Further, RSM based desirability approach is also used to obtain optimal process parameters and compared them with results obtained from R-method and found to be relatively close. © 2023 Taylor & Francis.