Showing papers in "Journal of The Brazilian Society of Mechanical Sciences and Engineering in 2020"
TL;DR: Simulation results obtained clearly indicate the superiority of WOA-PID controller over the other controllers for trajectory tracking, better settling time, and ITAE errors.
Abstract: In this work, we are interested to the PID control of nonlinear systems and more specially the control of a robot manipulator. The idea is to determine the optimal parameters ($$K_{p}, K_{i}$$ and $$K_{d}$$) of the controller using a novel algorithm of optimization called whale optimizer algorithm (WOA). To study the effectiveness of WOA-PID controller, its performance is compared with other controllers such as particle swarm optimization-PID (PSO-PID) and grey wolf optimizer-PID (GWO-PID). The model of robot manipulator and all controllers were tested using Simulink/MATLAB. Simulation results obtained clearly indicate the superiority of WOA-PID controller over the other controllers for trajectory tracking, better settling time, and ITAE errors.
103 citations
TL;DR: Operational modal analysis techniques OMA and ISMA are reviewed with their development over the years and their pros and cons discussed.
Abstract: Vibrations are the root cause of many mechanical and civil structure failures. Dynamic characteristics of a structure must be extracted to better understand structural vibrational problems. Modal analysis is used to determine the dynamic characteristics of a system like natural frequencies, damping ratios and mode shapes. Some of the applications of modal analysis include damage detection, design of a structure/machine for dynamic loading conditions and structural health monitoring. The techniques used for modal analysis are experimental modal analysis (EMA), operational modal analysis (OMA) and a less known technique called impact synchronous modal analysis (ISMA), which is a new development. EMA is performed in simulated controlled environment, while OMA and ISMA are performed when the system is in operation. Although EMA is the oldest modal analysis technique, there is an increasing interest in operational modal analysis techniques in recent years. In this paper, operational modal analysis techniques OMA and ISMA are reviewed with their development over the years and their pros and cons discussed.
58 citations
TL;DR: In this article, the Gurtin-Murdoch theory of elasticity together with the von Karman geometrical nonlinearity is implemented to the classical shell theory to construct an efficient size-dependent shell model.
Abstract: As one of the innovative materials, functionally graded (FG) composite materials have the capability to vary microstructure and design attributes from one side to other representing the desired material properties. The prime aim of this work is to analyze the surface stress effect on the nonlinear free vibration response of FG cylindrical nanoshells incorporating various modal interactions. To this end, the Gurtin–Murdoch theory of elasticity together with the von Karman geometrical nonlinearity is implemented to the classical shell theory to construct an efficient size-dependent shell model. In order to take the modal interactions between the main oscillation mode and various symmetric vibration modes, the lateral deflection of the FG nanoshell is expressed as combination of the simple main vibration mode and convergent symmetric modes. Thereafter, the solution of problem is considered as the summation of the homogenous and particular parts to put the Galerkin technique to use. Finally, the multiple time-scales method is employed to achieve analytical expression for the surface elastic-based frequency response of FG nanoshells. It is displayed that in the presence of modal interaction, by increasing the shell deflection, the value of the frequency ratio decreases while in the absence of modal interaction, it enhances.
39 citations
TL;DR: A comprehensive overview of micro-electrical discharge machining along with their recent trends and key challenges is presented in this article, where the sustainability of the system (micro-EDM) through green manufacturing is explored.
Abstract: Micro-electrical discharge machining is an indispensable tool to manufacture the component or parts of components at the micro-level with reasonable accuracy and precision. This article reports a comprehensive overview of micro-EDM along with their recent trends and key challenges. The sparking phenomenon, physical principle of material removal, process capabilities and flexibility with the other machining process are discussed in the initial part of the paper. Major development issues associated with nano-EDM are reviewed, and suggested solutions are proposed. Research and technology gaps enabling the transition from micro-EDM to nano-EDM are examined. The impact of discharge power technology and dielectric circulation is explored. Moreover, this review article explores the sustainability of the system (micro-EDM) through green manufacturing. A state-of-the-art has been studied in various aspects of micro-EDM. The promising future research scope is also noted in micro-EDM as well as in nano-EDM based on the electrical discharge.
39 citations
TL;DR: In this paper, the impact of the drilling parameters on the kerf angle (K) and roundness error (Re) of selected holes was investigated to determine quality characteristics of carbon fiber-reinforced polymer composites.
Abstract: In this study, carbon fiber-reinforced polymer (CFRP) composites with three different fiber orientation angles (M1: [0°/90°]s, M2: [+ 45°/− 45°]s, and M3: [0°/45°/90°/− 45°]s) were drilled (with and without pilot holes) on an abrasive water jet (AWJ) machine and the effect of the drilling parameters on the kerf angle (K) and roundness error (Re) of selected holes was investigated to determine quality characteristics. The first aim of the study was the single-objective optimization of drilling parameters for minimum K and Re individually. The second aim was the multi-objective optimization of drilling parameters for the simultaneous minimization of both K and Re. The Taguchi method was applied for single-objective optimization, while all steps of the Taguchi-based gray relational analysis were used for multi-objective optimization. Drilling experiments were performed using the L16 (44) orthogonal array. Four levels each for water pressure, stand-off distance, traverse feed rate, and hole diameter were selected as control factors. Analysis of experimental findings revealed that pilot drilling improved the kerf angle of the hole by 12.4% and the roundness error by 22.87%. Minimum kerf angle and roundness error were realized in the AWJ drilling of the M3 CFRP. The most effective parameter on kerf angle and roundness error in AWJ drilling of M1, M2, and M3 CFRP materials was water pressure (80.6%, 76.9%, and 73.8%, respectively), followed by stand-off distance (11.7%, 12.0%, and 13.5%),while other drilling parameters remained below 10%. The statistical evaluation and optimization results in this study can contribute to the evaluation of the AWJ machinability of CFRP composites.
37 citations
TL;DR: Abrasive water jet (AWJ) machining is an emerging technology that offers an excellent alternative among the various advanced machining processes due to its process capabilities and excellent machining quality as discussed by the authors.
Abstract: Fiber-reinforced composites have established as a high-performance composite of modern advanced structures in various sectors such as automotive, aerospace, and marine industries Non-conventional machining processes are preferred for the ease of manufacturing operations, which incorporates the machining of high strength and anisotropic material Non-conventional manufacturing processes produce complicated shaped profiles and better surface characteristics Abrasive water jet (AWJ) machining is an emerging technology that offers an excellent alternative among the various advanced machining processes due to its process capabilities and excellent machining quality AWJ machining has fascinated immense attention in the fields of fiber-reinforced composite materials to produce intricate industrial components and attracted the researchers and production industries It has become well-known in all key areas of researches Over the past 30 years, lots of research work has been carried out to describe the machining performances among the studied process parameters This paper reviews the research progresses and integrated functions of AWJ machining in terms of mechanism and machining performances, which includes aspects such as mathematical modeling and optimization AWJ machining procedure and performance capability are reviewed and depicted in detail Also, a comprehensive conclusion of this review, along with future perspective, is explored subsequently The current review work will help future researchers for the proper selection of different FRP material composite compositions and AWJ machining parameters to achieve better performances The collection of this review literature will also support the production operations in the future
37 citations
TL;DR: In this article, the authors investigated the mechanical, thermal and magnetic properties of polymeric composite matrix comprising of polylactic acid (PLA), polyvinyl chloride (PVC) reinforced with wood dust and magnetite (Fe3O4) powder for possible 4D printing applications.
Abstract: In the present study, investigations for mechanical, thermal and magnetic properties of polymeric composite matrix comprising of polylactic acid (PLA), polyvinyl chloride (PVC) reinforced with wood dust and magnetite (Fe3O4) powder have been reported for possible four-dimensional printing applications. PLA polymer shows 4D properties based upon external stimulus along with excellent mechanical properties. The reinforcement of PVC, wood dust and Fe3O4 in PLA affects the 4D capabilities of composite matrix, which has been explored in this work based upon coercivity, magnetization, retentivity along with tensile properties and thermal stability. It has been observed that mechanical processing with twin screw extrusion at 170 °C barrel temperature, 0.10 Nm torque and 10 kg load are the optimized parametric conditions for hybrid blend (composite composition/proportion PLA 50 wt%–PVC 25 wt%–Fe3O4 20 wt%–wood dust 5 wt%). Further, it has been ascertained that only screw temperature is significant parameter for controlling the mechanical properties of the extrudate. The results are supported by surface hardness, surface roughness (Ra), porosity percentage (%) and fractured surface analysis.
37 citations
TL;DR: Artificial neural network along with heuristic algorithms, namely particle swarm optimization (PSO) and simulated annealing (SA), has been employed to carry out the modeling and optimization procedure of electrical discharge machining (EDM) process on AISI2312 hot worked steel parts.
Abstract: In the present study, artificial neural network (ANN) along with heuristic algorithms, namely particle swarm optimization (PSO) and simulated annealing (SA), has been employed to carry out the modeling and optimization procedure of electrical discharge machining (EDM) process on AISI2312 hot worked steel parts. Surface roughness (SR), tool wear rate (TWR) and material removal rate (MRR) are the process quality measures considered as process output characteristics. Determination of a process variables (pulse on and off time, current, voltage and duty factor) combination to minimize TWR and SR and maximize MRR independently (as single objective) and also simultaneously (as multi-criteria) optimization is the main objective of this study. The experimental data are gathered using Taguchi L36 orthogonal array based on design of experiments approach. Next, the output measures are used to develop the ANN model. Furthermore, the architecture of the ANN has been modified using PSO algorithm. At the last step, in order to determine the best set of process output variables values for a desired set of process quality measures, the developed ANN model is embedded into proposed heuristic algorithms (SA and PSO) with which their derived results have been compared. It is evident that the proposed optimization procedure is quite efficient in modeling (with less than 1% error) and optimization (less than 4 and 7 percent error for single- and multi-objective optimizations, respectively) of EDM process variables.
36 citations
TL;DR: In this article, a dielectrophoresis microfluidic chip for particle separation was proposed, which uses dielectric properties to perform size-based fractionation of red blood cells and platelets.
Abstract: The paper proposes a dielectrophoresis microfluidic chip for particle separation, which uses dielectric properties to perform size-based fractionation of red blood cells and platelets. Based on the control variables, the distribution of the electric field in the chip and the trajectory of the particles in the microfluidic channel are calculated using COMSOL Multiphysics under different electrode shapes, voltages and chip exit structures. Both red blood cells and platelets respond to negative dielectrophoresis at an alternating current signal with a frequency of 100 kHz. The larger red blood cells are subjected to a stronger dielectrophoretic force than the platelets and are biased toward the right outlet, and the platelets flow out from the left outlet under the combined action of fluid force and dielectrophoretic force to achieve the purpose of separation. On this basis, through quantitative comparison and analysis, a more optimized microfluidic chip capable of effectively separating particles is finally selected.
35 citations
TL;DR: In this paper, a parametric analysis of rotating truncated conical shells reinforced with graphene nanoplatelets (GNPs) is presented for free vibration analysis, where the composite shell is considered to be composed of epoxy as the matrix and the GNPs which are distributed along the thickness direction based on various distribution patterns.
Abstract: In this paper, a parametric study is presented for free vibration analysis of rotating truncated conical shells reinforced with graphene nanoplatelets (GNPs). The composite shell is considered to be composed of epoxy as the matrix and the GNPs which are distributed along the thickness direction based on the various distribution patterns. The shell is modeled based on the first-order shear deformation theory (FSDT), and effective material properties are calculated based on the Halpin–Tsai model and the rule of mixture. Incorporating centrifugal and Coriolis accelerations along with initial hoop tension, the set of the governing equations and boundary conditions are derived using Hamilton’s principle and are solved numerically using generalized differential quadrature method. Convergence and accuracy of the presented solution are confirmed, and influences of various parameters on the forward and backward frequencies are investigated including circumferential mode number, boundary conditions, rotational speed, semi-vertex angle and also mass fraction, distribution pattern, width and thickness of the GNPs. It is noteworthy that for the first time, the initial hoop tension is incorporated for a rotating conical shell modeled based on the FSDT.
35 citations
TL;DR: In this paper, the authors extended the Kirchhoff-love model to thermal buckling and post-buckling analysis of functionally graded structures, where material properties of the FG structures were assumed to obey a power law distribution of the volume fraction of the constituents.
Abstract: In this paper, we extend the Kirchhoff–Love model to thermal buckling and post-buckling analysis of functionally graded structures. The kernel idea of the proposed model consists of the consideration of large displacements and finite rotation to accurately model the thermal effects on buckling and post-buckling behavior of such structures. Both uniform and nonuniform temperature distributions are considered. Material properties of the FG structures are graded in the thickness direction and assumed to obey a power law distribution of the volume fraction of the constituents. The effectiveness and usefulness of the proposed model are highlighted through different numerical examples, and the effects of the volume fraction exponent, thermal loads, length-to-thickness ratio, boundary conditions and geometrical parameters on the buckling and post-buckling behavior of FGM structures are also examined.
TL;DR: In this article, Al2O3 and CuO nanoparticles have been used to enhance the thermal efficiency of the heat exchangers (HEs) by upgrading the thermal properties of working fluid by utilizing nanoparticles.
Abstract: Different methods have been utilized to enhance the thermal efficiency of the heat exchangers (HEs). A widely used method to upgrade the thermal efficiency of HEs is upgrading the thermal properties of working fluid by utilizing nanoparticles. In this study, Al2O3 and CuO have been utilized to prepare Al2O3–CuO/water hybrid nanofluid. Accordingly, Al2O3 and CuO nanoparticles have been mixed into the water with 1% (50:50) weight concentration. The main objective of this work is testing the prepared hybrid nanofluid in plate-type HEs (PHEs) with 8, 12 and 16 plates to determine the influence of number of plates on heat transfer improvement by hybrid nanofluid. Experimental findings of the present study demonstrated that utilizing Al2O3–CuO/water hybrid-type nanofluid in the PHE enhanced thermal efficiency notably in comparison with single-type nanofluids. Using this hybrid nanofluid increased the thermal performance in all PHEs with different number of plates. However, it is observed that increasing number of plates led to more increment in thermal performance by utilizing hybrid nanofluid. The highest increment in overall heat transfer coefficient was obtained as 12%, 19% and 20% in PHEs with eight, 12 and 16 plates, respectively. In addition, the highest enhancement in effectiveness was achieved as 10%, 11.7% and 16% in PHEs with eight, 12 and 16 plates, respectively.
TL;DR: In this paper, a state of the art of aluminum matrix composite fabrication by friction stir processing route has been discussed with carefully mentioning the parameters associated with the process and microstructures and consequent mechanical properties of the composites have been evaluated.
Abstract: Aluminum matrix composites are widely used in aerospace, automotive industry and defense sector owing to its excellent weight-to-strength ratio. Friction stir processing has emerged as an excellent technique to produce particle reinforced as well as fiber reinforced aluminum matrix composites. This article is a state of the art of aluminum matrix composite fabrication by friction stir processing route. The fabrication procedure has been discussed with carefully mentioning the parameters associated with the process. Microstructures and consequent mechanical properties of the composites have been evaluated. Particular attention is given on the microstructural modification and strengthening mechanism. Also the wear and corrosion behavior of the composites has been discussed thoroughly. Finally, the article has been concluded with some suggestions toward future work.
TL;DR: In this article, Al2O3 and TiO2 nanoparticles with the size of 20nm were completely dispersed in distilled water and circulated in a minichannel heat sink.
Abstract: Nanofluids are known as a new generation of coolants. These fluids have attracted more attention in cooling applications, like electrical, optical, and solar systems recently, because of their unique rheological and thermal properties. In the present study, to evaluate the thermal behavior of the nanofluids, Al2O3 and TiO2 nanoparticles with the size of 20 nm were completely dispersed in distilled water and circulated in a minichannel heat sink. The heat sink consists of 10 minichannels that have designed to cool thermoelectric generators. The results showed that by only dispersion of 0.5 vol% Al2O3 nanoparticles a 9.30% heat transfer enhancement observed. It was also obtained that the TiO2-water sample showed a 4.56% heat transfer enhancement. The highest efficiency was obtained by utilizing the Al2O3-water nanofluid. This was attributed to the higher thermal conductivity of Al2O3 compared to TiO2. Using both nanofluids resulted in higher pressure drop compared to the based fluid. At the Reynolds number of 1000, the pressure drop for Al2O3 and TiO2 nanofluids increased as 3.33% and 3.88%, respectively. The increased pressure drop was attributed to higher density and viscosity of nanofluids. The classical theories are not available to justify the remarkable heat transfer enhancement obtained by adding a negligible amount of mentioned nanoparticles. It seems that new mechanisms such as the random motion of nanoparticles and generated microconvections by nanoparticle motion in the base fluid are responsible for considerable heat transfer enhancement.
TL;DR: In this paper, the performance of graphite nano-fluid-assisted minimum quantity lubrication (MQL) in turning of Ti alloy (grade II) using CBN tool were evaluated regarding the cutting force, cutting temperature and surface roughness.
Abstract: Recently, the urgency of improved machining performance and environmental sustainability has forced the manufacturer to seek for alternative cooling and lubricating agent/technique such as nano-fluid (NF)-assisted minimum quantity lubrication (MQL). In this context, the performances of aluminum oxide (Al2O3), molybdenum disulfide (MoS2) and graphite (C) NF-impinged MQL in turning of Ti alloy (grade II) using CBN tool were evaluated regarding the cutting force, cutting temperature and surface roughness. The cutting speed, feed rate, approaching angle and cutting conditions (i.e., NFs) were oriented following the Box–Behnken design-of-experiment. The experimental results showed that the graphite NF, compared to Al2O3 and MoS2, revealed the lowest cutting force, temperature and roughness. Moreover, it is evident from SEM images that graphite NF revealed a smoother machined surface and tool profile. This smooth tool and workpiece surface profile can be accredited to graphite’s role as a nano-lubricant and its breaking ability into smaller NFs under pressure. To make the study complete, the adaptive neuro-fuzzy inference system (ANFIS) was employed to predict, the response surface methodology (RSM) was used to mathematically model, and the composite desirability approach (CDA) was used to optimize the responses. A good agreement between the experimental and modeled observations was found; however, the ANFIS outperformed the RSM. Moreover, the analysis of variance exhibited that the cutting force and temperature were primarily influenced by the cutting speed and the surface roughness was afflicted mostly by the feed.
TL;DR: The meshing contact analysis method considers the interactive influence of the manufacturing error and modification shape of tooth profile on the Meshing contact status of RV transmission; the cycloidal tooth profile can be obtained which is more suitable for engineering practice.
Abstract: The manufacturing error of cycloid gear is the key factor affecting the transmission precision and meshing characteristics of cycloidal-pin gear in RV reducer. Taking the RV cycloidal-pin gear pair transmission as the object, a meshing contact analysis method is proposed for RV cycloidal-pin gear transmission considering the influence of manufacturing error. The modified tooth profile of cycloid gear is effectively superimposed and transformed by taking the influence of tooth profile and pitch errors of cycloidal gear into consideration, and the theoretical contact analysis model of cycloidal-pin gear transmission is established. By analyzing and solving the meshing contact model, the characteristic parameters such as the meshing point position, meshing backlash and transmission error of cycloidal-pin gear between the meshing contact surfaces are obtained under the influence of manufacturing error, and the effective pre-control of the tooth profile and the meshing contact performance is realized. The verification analysis results show that the manufacturing error has a great influence on the transmission accuracy of RV cycloidal-pin gear, among which the tooth pitch error has the greatest influence on the transmission error, which is in a positive proportion. And the influence of tooth profile error on transmission error is second. The meshing contact analysis method considers the interactive influence of the manufacturing error and modification shape of tooth profile on the meshing contact status of RV transmission; the cycloidal tooth profile can be obtained which is more suitable for engineering practice. This analysis method can provide the theoretical support and technical means for profile modification design, motion accuracy improvement and load-bearing contact analysis of RV transmission.
TL;DR: In this paper, a review on hybrid polymer composites focuses on the mechanical properties such as impact, flexural and tensile strengths of hybrid polymeric composites so as to bring out the essence of their mechanical behaviour which are influenced by critical factors like selection of type, orientation and arrangement of reinforcements in polymer matrix composites.
Abstract: Polymer composites have become one of the most important domains in recent times for researchers. It is due to the fact that polymer composites possess better strength-to-weight ratio than the most of the conventional alloys and composites which are in use today for structural applications. Moreover, the researchers are also coming up with novel hybrid polymer composites so as to achieve the desired mechanical properties. Therefore, this review on hybrid polymer composites focuses on the mechanical properties like impact, flexural and tensile strengths of hybrid polymer composites so as to bring out the essence of their mechanical behaviour which are influenced by critical factors like selection of type, orientation and arrangement of reinforcements in polymer matrix composites. This detailed review is an endeavour to unfold the major aspects of this domain as research gaps which are untouched till date. The study shows that there is limited use of fillers (such as red mud and fly ash) and natural fibres (abaca, bamboo, ramie, coir, pineapple) in hybrid polymer composites to harness their full potential. It is also inferred from the study that there is a dearth of research pertinent to modelling, prediction and optimisation of mechanical properties of hybrid polymer composites like toughness, flexural strength, tensile strength and impact strength.
TL;DR: In this article, the authors formulated CuO-H2O nanofluids in a two-dimensional circular geometry with a rhombus-shaped barrier maintaining the constant temperature of two adjacent high walls.
Abstract: The heat transfer properties of current liquids are specifically improved by suspending nanocrystalline solid elements smaller than 100 nm in diameter. These liquids are considered as potential working fluids for applications such as car radiators, solar collectors, electronic frost systems, nuclear reactors and heat pipes. Due to such uses, here we formulate CuO–H2O nanofluids in a two-dimensional circular geometry with a rhombus-shaped barrier maintaining the constant temperature of two adjacent high walls. The streamlines and isotherms have been plotted using the control volume finite element method and applying the KKL model for nanofluid simulation. The results were calculated for different concentrations of nanoparticles, Hartmann number and Rayleigh number. It was found that in a large number of volume fraction and Hartmann number, the isotherms near the outer margin are more prominent while the low-volume-concentration isotherms are concentrated near the adiabatic wall of the obstacle. It was also found that there is a temperature gradient in the radial direction at a higher volume fraction and Hartmann number (Ha). The temperature gradient was limited to adiabatic walls of the obstruction in lower volume fraction and Ha. Two similar shapes but differently directed eddies are formed for any value of Ra in streamlines. |Ψmax|nf increases with an increase in the values of Ra from 103 to 105.
TL;DR: In this paper, the feasibility of low-cost multilayer (TiCN/Al2O3/TiN) coated carbide tool in hard machining applications and the propitious role of minimum quantity lubrication using graphene nanoparticles with enriched radiator coolant-based nano-cutting fluid for machinability improvement in hardened steel.
Abstract: Efficient cooling and lubrication techniques are required to obtain sustainable machining of difficult-to-cut materials, which are the pillars of aerospace, automotive, medical and nuclear industries. Excessive cutting fluid is required and consumed in machining difficult-to-machine materials with high-pressure coolant supplies. Nanofluid-assisted minimum quantity lubrication (NFMQL) is adorned with improved machining performance and environmental sustainability. The present work addresses the surface integrity and chip morphology in finish hard turning of AISI D3 steel under NFMQL condition. The surface integrity aspects include microhardness, residual stress, white layer formation, machined surface morphology, and surface roughness. This experimental investigation aims to explore the feasibility of low-cost multilayer (TiCN/Al2O3/TiN) coated carbide tool in hard machining applications and to assess the propitious role of minimum quantity lubrication using graphene nanoparticles with enriched radiator coolant-based nano-cutting fluid for machinability improvement in hardened steel. Combined approach of central composite design—analysis of variance, desirability function analysis, and response surface methodology, has been subsequently employed for experimental investigation, predictive modelling, and optimization of surface roughness. With a motivational philosophy of “Go Green-Think Green-Act Green”, the work also deals with economic analysis and sustainability assessment under environmental-friendly NFMQL condition. It is expected that the found optimized parameters can contribute to machining end-outcomes such as an improved surface finish and reduced machining cost. The results showed that machining with NFMQL provided an effective cooling–lubrication strategy, safer and cleaner production, environmental friendliness and assisted in improving sustainability. In conclusion, the proposed NFMQL turning strategy is a robust method validated by statistical analysis for large industrial applications, especially in mould and die making sectors.
TL;DR: The time delay neural network (TDNN) aims at detecting road friction coefficient under lateral force excitations avoiding the use of standard mathematical tire models, which may provide a more efficient method with robust results.
Abstract: The performance of vehicle active safety systems is dependent on the friction force arising from the contact of tires and the road surface. Therefore, an adequate knowledge of the tire–road friction coefficient is of great importance to achieve a good performance of different vehicle control systems. This paper deals with the tire–road friction coefficient estimation problem through the knowledge of lateral tire force. A time delay neural network (TDNN) is adopted for the proposed estimation design. The TDNN aims at detecting road friction coefficient under lateral force excitations avoiding the use of standard mathematical tire models, which may provide a more efficient method with robust results. Moreover, the approach is able to estimate the road friction at each wheel independently, instead of using lumped axle models simplifications. Simulations based on a realistic vehicle model are carried out on different road surfaces and driving maneuvers to verify the effectiveness of the proposed estimation method. The results are compared with a classical approach, a model-based method modeled as a nonlinear regression.
TL;DR: In this article, boron carbide reinforcement within AA6061 alloy is investigated in terms of its mechanical and tribological properties, including tensile strength, bending strength, impact strength, shear properties and micro-hardness.
Abstract: The use of boron carbide-reinforced aluminium matrix composites has grown rapidly in critical applications of aerospace industries, automotive sectors, military, and nuclear engineering. However, boron carbide reinforcement within AA6061 alloy is worthy of investigation in terms of its mechanical and tribological properties. Novel aluminium matrix composites were developed with three different reinforcements (i.e. 5, 10, and 15 wt% of B4C) by using the stir casting process. The developed samples were then tested for performance in terms of mechanical properties (i.e. tensile strength, bending strength, impact strength, shear properties, and micro-hardness). The microstructure of the developed samples was analysed using a scanning electron microscope. By adding 5% B4C reinforcement, the samples display enhanced mechanical properties (high bending, increased resistance to impact test, and shear strength). The micro-hardness tends to increase by increasing the percentage of reinforcement. The novel composites have superior wear resistance due to an increase in the content of B4C particles. The measurements indicate that the wear rate resistance is significantly higher for the composite material with a large amount of B4C particles when was compared with AA6061 alloy. The patterns of surface analysis reveal a homogeneous distribution of ceramic reinforcements in 5 and 15 wt% of B4C samples, as well as a low agglomeration of embedded particles.
TL;DR: In this paper, carbon nanotubes (CNTs) enhanced with paraffin as a novel energy storage material for desalination application were investigated and the authors concluded that CNT enhanced paraffins is a better potential storage material as compared to conventional paraffiners in solar desalification application.
Abstract: The present study aims to find the technical feasibility of recently evolved nanomaterial, i.e. carbon nanotubes (CNT), enhanced with paraffin as a novel energy storage material for desalination application. As a primary investigation, the thermo-mechanical properties like density, melting point, thermal conductivity, etc., of CNT enhanced paraffin were first analysed and then integrated with solar desalination application. Three solar desalination stills: (i) conventional solar still, (ii) solar still loaded with fossil paraffin and (iii) solar still loaded with CNT-doped paraffin were fabricated and experimented at Chennai, India (Lat. 13° 08′ N, Long. 80° 27′ E). From the investigation, it is inferred that there is a significant increase (of about 26%) observed in the thermal conductivity of CNT-doped paraffin as compared to fossil paraffin. The cumulative yield of the conventional still, solar still with paraffin and solar still with CNT enhanced paraffin was found to be 2.5 kg/m2, 3.4 kg/m2 and 5.8 kg/m2, respectively. There was 41.4% and 26.4% enhancement, respectively, observed in the daily yield of the solar still with CNT-doped paraffin as compared to conventional still and the still with virgin paraffin. The productivity efficiency was 46.45% for the still with CNT blended paraffin contributing to 24% and 19.6% increase in the efficiency as compared to the other two stills considered for experimentation in this study. Thus, it is concluded that CNT enhanced paraffin is identified as a better potential energy storage material as compared to conventional paraffin in solar desalination application.
TL;DR: In this article, the machinability properties of these alloys were determined by turning, and they were associated with structural and mechanical properties of the alloys, and the minimum thrust force and surface roughness occurred in Al-7Si-4Zn-3Cu alloy, while the maximum built-up edge was observed during drilling.
Abstract: Al–7Si, Al–7Si–4Zn, Al–7Si–4Zn–3Cu alloys were produced by permanent mold casting method to investigate the effects of copper and zinc additions on the machinability properties of Al–7Si alloy. The structural and mechanical properties of the produced alloys were investigated with conventional methods. Machinability properties of these alloys were determined by turning, and they were associated with structural and mechanical properties of the alloys. Machinability experiments were carried out in CNC vertical machining center under dry cutting conditions using uncoated carbide drill and constant cutting speed (120 m/min), feed (0.15 mm/rev) and depth of cut (15 mm) values. The microstructure of Al–7Si binary alloy was observed to be composed of aluminum-rich α phase, primary silicon crystals and eutectic Al–Si phase. The addition of 4% Zn to the Al–7Si alloy did not form a different phase in the microstructure. However, Al2Cu intermetallic phase was formed by addition of 3% Cu. While the hardness and tensile strength of the alloy increased, elongation to fracture significantly reduced. As a result of machinability experiments, it was observed that the minimum thrust force and surface roughness occurred in Al–7Si–4Zn–3Cu alloy, while the maximum built-up edge was observed during drilling of Al–7Si and Al–7Si–4Zn alloys. Microhardness value of machined surface in Al–7Si alloy was found to be the minimum while the maximum Al–7Si–4Zn–3Cu alloy was observed.
TL;DR: In this paper, the effect of surface roughness induced during the bone drilling operation on pullout strength with rotary ultrasonic bone drilling (RUBD) and standard conventional bone drilling was studied.
Abstract: Drilling of bone is required to repair and align the bone when faced with a major fracture. The screw and implant are used for fixing the fractured part of the bone. The failure of osteosynthesis is due to strength between the bone and screw, which majorly depends upon the pull-out strength of the cortical screw. Pull-out strength is the force required to pull a screw out of its foundation from the bone. After the fixation of cortical screws, the major forces acting on the fixation of the screw and the implanted device in the bone. Therefore, it needs to make sure that the screw must fit into the place and grasp the bone within the drilled hole. The intended focus of this research is to see the effect of surface roughness induced during the bone drilling operation on pull-out strength with rotary ultrasonic bone drilling (RUBD) and standard conventional bone drilling (CBD). This is observed that a drilled hole in a bone exhibits greater pull-out strength with more surface roughness because more anchoring is provided by the roughened surface. Also, the apatite formation of the bone shows the biocompatible nature of porcine bone in the simulated body fluid (SBF) solution. RUBD using different grit size in a hollow drilling burr resulted that coarse abrasive have maximum effort for higher surface roughness. Furthermore, the higher surface texture provides a better bone growth rate as it provides peaks for branching and nucleation when preserved in SBF. RUBD provides precise cutting to the bone as compared to CBD. On the 28th day of the bone-screw samples to be immersed in SBF results 42.82% higher pull-out strength of screw in case of RUBD as compared to CBD.
TL;DR: A CNN input mode for bearing fault recognition is proposed based on time-domain color feature diagram (TDCF) through adding red color to diagrams that significantly enhanced the fault characteristics of the signal, which is beneficial to the CNN extraction of bearing fault features.
Abstract: Convolutional neural networks (CNNs) have been applied to the field of fault diagnosis as one of the most widely used deep learning architectures. Different input modes of CNN for bearing fault identification were analyzed by researchers to improve recognition accuracy, such as time-domain diagram, grayscale diagram, short-time Fourier transform diagram, and continuous wavelet transform diagram. However, for the data with small sample size and high background noise, the performance of the CNN is constrained. In this paper, one CNN input mode for bearing fault recognition is proposed based on time-domain color feature diagram (TDCF) through adding red color to diagrams. The method significantly enhanced the fault characteristics of the signal, which is beneficial to the CNN extraction of bearing fault features. Convolution visualization illustrates the effectiveness of the proposed method that provides more bearing fault recognition information. Different sample size and color rate were analyzed by bearing vibration data with high noise. The results showed that the bearing fault identification method based on CNN with 0.4 TDCF obtained a highest fault identification accuracy compared with other input mode methods. The feasibility of the proposed method has been validated, which also provides one reference for other faults identification and pattern recognition.
TL;DR: In this paper, the effect and control of FDM process parameters, i.e., layer thickness, raster angle, infill density and internal structure, on surface roughness, build time and compressive strength of developed biomedical implant parts was presented.
Abstract: Fused deposition modeling (FDM) is a widely used additive manufacturing (AM) technique for developing complex features and geometries within the shortest possible time as per customer needs. Nowadays, the customization of biomedical parts is becoming possible due to the increasing accuracy and enhanced ability of FDM machines to control the process parameters. The control on surface quality of parts produced by FDM process is of prime concern for the researchers, which are induced due to the stair steps on sloping surfaces, and needs addressing. In addition, to meet customer demands rapidly, the FDM part build time must be reduced without much compromising the strength of the parts necessary for specific applications. In the same context, this paper presents the effect and control of FDM process parameters, i.e., layer thickness, raster angle, infill density and internal structure, on surface roughness, build time and compressive strength of developed biomedical implant parts. The face-centered central composite design is employed to consummate the experimental trials, and experimental data are used to establish an adaptive neuro-fuzzy inference system (ANFIS) model for predicting the surface roughness, build time and compressive strength with respect to changes in FDM process parameters. At the end, whale optimization algorithm (WOA) has been applied to minimize surface roughness, minimize build time and maximize compressive strength simultaneously. Then, the optimal solutions obtained from WOA methodology have been compared with ANFIS predicted results. The results reveal that ANFIS-WOA methodology provides optimal combination of FDM process parameters accurately.
TL;DR: In this paper, the authors examined thermal performance and relevant flow phenomena of a flat plate closed-loop pulsating heat pipe (FP-CLPHP) filled with binary mixtures.
Abstract: The present study basically examines thermal performance and relevant flow phenomena of a flat plate closed-loop pulsating heat pipe (FP-CLPHP) filled with binary mixtures. The heat pipe has eight turns, each of which consisting of asymmetrical channel pairs having cross sections as 2 mm × 2 mm and 1 mm × 2 mm (width × height). Binary mixtures are generated as mixtures of ethanol (E) and pentane (P) with different mixing ratios. Mainly, effects of volume mixing ratio (E/P = 1:1, 1:3 and 3:1), vertical (90°) and horizontal orientation (0°) and filling ratio (30% and 60%) on thermal characteristics are investigated under different heat inputs. For examination of flow dynamics, images are obtained by using a high-speed camera at 1000 fps. The results show that variation of volumetric percentage of each component significantly changes thermal performance. Increasing pentane in the mixture improves the thermal performance, such that heat pipe with mixing ratio of E/P = 1:3 can properly operate even at horizontal position. On the other hand, increasing volume of ethanol in mixture leads to collapse of the FP-CLPHP at both orientations (0° and 90°). Generally, the filling ratio of 30% shows better thermal performance. Complex bubble–liquid interactions and dynamics play critical roles on thermal characteristics. Two novel characteristic phenomena are identified for non-uniform PHPs: (1) flooding phenomenon and (2) asymmetrical rapid bubble growth phenomenon.
TL;DR: In this article, a nonlinear dynamic model of high contact ratio gears with multiple clearances is established by the lumped mass method, in which time-varying mesh stiffness (TVMS), static transmission error, gear backlash, and bearing radial clearance are taken into consideration as well.
Abstract: A brief research status on high contact ratio gears (HCRG) is first conducted to obtain a basic understanding. Subsequently, a nonlinear dynamic model of HCRG with multiple clearances is established by the lumped mass method, in which time-varying mesh stiffness (TVMS), static transmission error, gear backlash, and bearing radial clearance are taken into consideration as well. The TVMS of HCRG is calculated based on an improved potential energy model and then fitted into a Fourier series form. After the dimensionless treatment, the system differential equations of motion are solved using Runge–Kutta numerical integration method. With the help of bifurcation diagrams, largest Lyapunov exponent charts, time-domain waveforms, FFT spectra, Poincare maps, and phase diagrams, the influence of excitation frequency, gear backlash, mesh damping ratio, error fluctuation, and bearing radial clearance on the nonlinear dynamic characteristics of the system is investigated in detail. The results show that with the changes of these analysis parameters, the system exhibits different types of nonlinear behaviors and dynamic evolution mechanism, including period-one, multi-periodic, quasi-periodic, chaotic motions, and jump discontinuity phenomenon. Meanwhile, three typical routes to chaos, namely period-doubling bifurcation to chaos, quasi-period to chaos, and crisis to chaos, are also demonstrated. Additionally, it is found that the bearing radial clearance produces a weaker nonlinear coupling effect when compared to gear backlash. The research results can provide a certain theoretical support for the dynamic design and vibration control of the HCRG.
TL;DR: In this paper, the effect of heat input on the shape stability and the microstructure evolution of the walls was studied, and the results indicated that the alternating depositing direction strategy was more suited to build thin walls with relatively regular height.
Abstract: Among metal-based additive manufacturing, wire and arc additive manufacturing is receiving increasing attention for the production of components with medium to large dimensions. In the current research, the production of low-carbon steel thin-walled components by wire and arc additive manufacturing was addressed. Firstly, the influence of two depositing direction strategies on the wall shape was investigated. Subsequently, the effect of heat input on the shape stability and the microstructure evolution of the walls was studied. The results indicated that the alternating depositing direction strategy was more suited to build thin walls with relatively regular height. The heat input significantly influenced the shape stability, but had slight effects on the microstructure evolution. The microstructure of the walls varied from the top to the bottom regions, leading to a variation in hardness from 157 ± 3.11 to 192 ± 4.30 (HV5). The microstructure of the built thin walls can be distinguished in three regions: The upper region exhibited lamellar structures; the middle region dominantly featured granular structures of ferrites with a small proportion of pearlites, which appear in the boundaries of grains; and the lower region showed a mix of lamellar and equiaxed structures of ferrites. The tensile properties of the built material also exhibited anisotropic characteristics: The yield strength and ultimate tensile strength vary from 320 ± 6 to 362 ± 8 MPa and from 429 ± 8 to 479 ± 7 MPa, respectively.
TL;DR: In this article, an experimental investigation on the energy absorption capability of glass/carbon intraply hybrid filament wound composite pipes subjected to quasi-static lateral compression loading was carried out, where composite pipes with different fiber orientation angles were fabricated for both hybrid and non-hybrid to systematically analyze the performance of intra-ply hybridization process.
Abstract: The current study aimed to examine an experimental investigation on the energy absorption capability of glass/carbon intraply hybrid filament wound composite pipes subjected to quasi-static lateral compression loading The composite pipes with different fiber orientation angles were fabricated for both hybrid and non-hybrid to systematically analyze the performance of intraply hybridization process At least 5 samples of each composite pipe configuration were tested to obtain the load–displacement curves and fracture patterns The failure modes and fracture mechanisms of crushed samples were discussed to establish the influence of hybridization on crashworthiness parameters through load–displacement response Separation between the layers (delamination) was occurred as the main damage mechanism in all samples Hybridization with glass fiber significantly increased the energy absorption capability and load carrying capacity of carbon fiber-reinforced composite pipes Their crushing values were found as between the values of pipes made of glass fiber and carbon fiber as expected Furthermore, hybridization provided to opportunity of more stable load–displacement response for crushing process An increment in fiber orientation angle was also led to increase in energy absorption capability and load carrying capacity The pipe made of glass with higher fiber orientation had the best specific energy absorption