Advances in Metrology and Measurement of Engineering Surfaces

The aim of the present work is to provide a parametric analysis of stress intensity factor (SIF) in different functionally graded material (FGM) plates using the extended finite element method (XFEM). Exponential, power laws and sigmoid functions have been used for the material gradation of FGM plates. The relations of SIF have been presented with crack length and FGM material properties such as material modulus ratio, FGM layer thickness and power-law index. The present work reveals that the FGM material properties considerably affect the SIF values. Out of four FGM material models considered in this study, the sigmoid FGM model shows the least value of SIF.

The main aim of this paper is to study the mechanical properties of the weld also the microstructure of the weld joints were analyzed. The effects of sensitization of gas tungsten arc (GTA) welded 304L stainless steel (SS) joints were observed. 304L stainless steel was heated to 450–950 °C, soaked for 0.5–2 h, and was observed. The three heat groups were chosen from the operative window of tungsten inert gas welding; these heat groups are low heat -2200 J/mm, medium heat–3320 J/mm, and high heat 3800 J/mm. Using these heat groups, weld joints were made which were normalized at 750 °C, 850 °C, and 1000 °C for 0.5 h, 1 h, and 2 h, respectively. These specimens were used to perform tensile test, impact strength test, microstructure, and microhardness for welded joint. The effect of sensitization was observed for these joints for stated mechanical properties. The outcomes of this study indicate that the tensile strength is maximum at weld joints normalized at 750 °C but remarkably decreased as the temperature was increased while the yield strength did not notably change with increasing of the temperature. The Charpy impact energy and micro-harness showed higher value at weld joints normalized at 750 °C but remarkably decreased as the temperature was increased. The major reason for Charpy impact energy decrease was compound of manganese–silicon–Sulfur formed in the weld pool during solidification. The microstructures of sensitized samples have been observed by optical microscope. The sensitization was found to be more for heat-treated welded joints and parent metal as compared to unprocessed weld joints and parent metal. Precisely, welded joints were normalized at 850 °C with soaking time 2 h and allowed to cool in a furnace was observed to be more sensitized.

Aluminum alloy 6061 and aluminum alloy 7075 (or simply denoted as Al 6061 and Al 7075, respectively) are widely used in the field of aviation, automobiles, and marine due to their exceptional properties such as good strength, lightweight, and better corrosion. In this paper, Al 6061 and Al 7075 are used as base materials for reinforcement to further enhance their mechanical properties. Alumina, silicon carbide, boron carbide, and titanium oxide are used as reinforcement particles. The cross matrix composites of Al 6061 and Al 7075 are produced by the widely used stir casting method. The different weight percentages of reinforcement particles are used to prepare different composition of cross composites. The resultant composites are heat-treated in T6 condition and machined in the suitable dimension for testing. The mechanical characterization was carried out by performing hardness, tensile, and impact tests, and their results have been presented. Moreover, the comparison of mechanical properties of alloys Al 6061 and Al 7075 is also given; specifically, the tensile stress and impact value of Al 6061 are shown to be increased when the reinforcement particles are added comparing to Al 7075 cross composites.

Nowadays, because of the issues related to the environment, it is becoming mandatory for the usage of eco-friendly products for betterment of the people. Hence, here is an attempt made where the harmful synthetic fibre composites used for marine, automobile, constructive applications can be replaced by eco-friendly, biodegradable natural areca fibre composites. Physical properties of areca husk fibre were studied, and it revealed that maximum fibres have length range from 40 to 50 mm with the diameter ranging from 0.200 to 0.299 mm. These untreated and 1% NaOH treated fibres were used for composite fabrication at different fibre loadings like 45, 50, 55, 60, and 65%. It was found that 50% is the optimum fibre percentage. Tensile strength and flexural strength for untreated fibre composite at 50% fibre loading were found to be 7.40 N/mm² and 4.01 N/mm², respectively, and 54.91 N/mm² and 6.81 N/mm², respectively, for alkali-treated fibre composites.

Bearing is an integral part of the machine tools system, but due to contact stress, wear is induced, which decreases the life of the machine tools and bearing system. Stress developed due to contact between mating surfaces, i.e., contact stress and friction forces, is the main factor which is affecting the efficiency of a system. To achieve efficiency or to make contact-less levitation, active magnetic bearing are most suitable. This paper gives a basic idea on control techniques and failure modes and their effect on the active magnetic bearing system, by which frictional forces and the vibration should be minimised, which are the primary cause of wear and tear and decentralisation of the shaft. AMB systems are more suitable to increase the life and performance of the machine tools.

The cutting temperature and the amount of heat produced at the tool–chip interface during different machining operations have been recognized as main factors that influence the cost of machining as well as the cutting tool performance in terms of surface finish and the production time involved while machining. Cutting tool efficiency is largely affected by temperature generated while machining which limits the quality of the finished product. This paper presents a review of various methods for the measurement of tool and workpiece temperature distribution in different machining processes. Different temperature-sensing techniques are discussed along with their limitations. A comparison between several sensing methods has been done in terms of cost-benefit, accuracy, ease in measurement and response time in order to find out the best-suited method.

Stirrup making is a process to angling reinforcement bars at expected edges into civil engineering work. Hand-operated bar bending requires vigorous physical exercise, which is generally done in a bad ergonomic atmosphere at construction site. This could begin to prolonged musculoskeletal complications such as profound back disorder among bar benders. Current research explains a numerical model for number of bends, torque and required time to process of a stirrup making method using human fortified flywheel motor based on testing data collected, applying a method of design for experimentation. Out of the above three models, the numerical model and its analysis for a number of bend for the stirrup producing process is described here. Findings obtained by the numerical model for a number of bends positively describes the degree of interaction of multiple independent parameters for stirrup producing operation.

This paper reports the numerical analysis of single-phase kerosene-based ferrofluid that passes through a circular-shaped closed loop. Permanent magnet has been employed to generate the magnetic field, and fluid flows as per thermo-magnetic convection principle. A two-dimensional, incompressible, and laminar flow has been considered while performing the time-dependent heat transfer study for the ferrofluid. The governing equations such as continuity, momentum, and energy equations are solved for steady-state incompressible flow using a partial differential equation based multiphysics finite element software, COMSOL Multiphysics 5.0. Simulation results indicate that magnitude of Kelvin body force rises with time as fluid flows with increased velocity resulting in successful dissipation of heat flux.

Charoli (Buchanania lanzan) is a vital multipurpose tree and essential plant for a rural and tribal economy. Charoli tree gives food, fuel, fodder, wood, and medicine to the local rural and tribal society. In traditional ways, this Charoli kernel removal is made manually by using hammer and hands due to which there is lower efficiency with damaged and broken kernels. Hence, there is a demand to create an indigenous and sustainable design of Charoli nut desheller for improvement in Charoli nut processing efficiency and reducing the wastage occurring due to kernel damage. In this investigation, a theoretical mathematical model based on a dimensional analysis method was disclosed to identify the quantity of deshelled nut of a Charoli nut deshelling process. Dimensional analysis applying the Buckingham Pi (π) theorem was adopted to get an effective relationship among the quantity of deshelled nut and independent variables. Independent variables comprise diameter of grinding disk, thickness of grinding disk, number of grinding disk, clearance between two rotating disks, energy of flywheel, angular speed, time to speed up the flywheel, % moisture content, hardness of nut, moment of inertia of flywheel, gear ratio, bulk density of nut, and feed rate. Established relation is useful to the prediction of behavior between dependent and independent variables corresponding to the different process conditions.

This paper deals with the investigations for controlling dimensional deviations of 3D printed thermoplastic composite matrix-based prototypes with fused deposition modelling (FDM). The dimensional deviation results suggested that infill density 60%, infill angle 45° and infill speed of 70 mm/s are the optimized printing condition, but only infill density is the significant parameter in the present investigation. Surface hardness analysis supported the observed trend for dimensional deviation. It has been observed that the 3D printed prototype held very low electrical conductivity (<10⁻⁶ S/cm) and was suitable for structural engineering applications.

In this paper, the contribution of dispersed graphene nanoparticles in graphene-gear oil nanolubricant has been analyzed. Synthesis of nanolubricant has been performed using the two-step method. The nanoparticles have been dispersed in the range of 0.03–1.8% by volume in industrial gear oil (SAE EP90). Viscosity and density of nanolubricant are measured by using Stabinger viscometer (SVM 3000, M/S Anton-Paar). Rheological properties have been experimentally tested in the temperature range of 20–80 °C, and the results have been compared with theoretically available models in open literature. The performance characteristics of nanolubricants in hydrodynamic lubrication regime have been evaluated by considering the standard Reynolds equation. For this purpose, the geometry of an infinite Rayleigh step slider bearing (one dimension) is considered with defined boundary conditions. Finite difference method (FDM) is used to obtain the solution of boundary value problem. Results confirm that the dispersion of graphene nanoparticles in gear oil enhances the performance of lubrication.

This paper focuses on the effect of two-step austempering on abrasion wear characteristics of the ductile cast iron. The single-step (conventional) and two-step austempering were employed for the samples. There were four treatments. For all samples, austenitization at 900 °C was done. The first treatment comprised of conventional austempering at 400 °C. The second one consisted of conventional austempering at 320 °C. The third one consisted of austempering at 400 °C followed by austempering at 320 °C. The fourth one comprised of austempering at 320 °C followed by austempering at 400 °C. The results showed that samples with two-step austempered at 320 °C followed by 400 °C exhibited enhanced abrasion resistance. The reason for this behavior is discussed considering the microstructure parameters.

In the present work, the effect of particle content and operating temperature on secondary stage creep in the thick composite cylinder is analyzed. The cylinder is made of Al-SiC_p and is exposed to internal pressure only. Threshold’s creep law is used for creep analysis of the thick composite cylinder under plane stress. The analysis is carried out and results are obtained by varying material parameters. Marginal variations in radial, tangential and effective stresses are noticed. However, strain rates show considerable change by increasing the particle content and decreasing operating temperature.

In the present study, we use wind tunnel model as a medium to calculate and analyze the flow velocity of the air passes through any aerodynamic medium and besides automobile too. An experimental study was carried out on a wind tunnel to evaluate and optimize the performance and results of the model obtained. Experiments were carried out with four different instruments, i.e., Yaw Sphere, Claw Yaw Meter, Pressure Sphere (multi-hole probe), Turbulence Sphere to obtain velocity data. According to the experiments and studies carried out, Pressure Sphere provides us with exact velocity and pressure value when compared to the other three instruments. Using this new kind of instrument, faults can be minimized when compared to the previous instruments.

Present work discusses the role of metal coatings on the piston rings material for the enhancement of its wear and friction properties. Coatings of zinc (Zn) and zinc and chromium (Cr) have been developed on the piston rings material using the electroplating technique. Wear and friction properties were evaluated using a linear reciprocating tribometer (LRT) in unlubricated condition. It is observed that zinc and zinc + chromium both the coatings have improved the wear resistance of the piston rings material; however, the improvement by Zinc alone was not that much significant. There was an improvement of 11% by zinc coating and 59% by zinc and chromium coating in the wear resistance. The coefficient of friction between the piston rings material and cylinder linear reduced up to 17% with the zinc and chromium coating. A finite element model has also been modeled for the prediction of maximum stress and strain area on the pin and plate surface for all the considered experimental runs.

Nanofluids improve the performance of thermal systems. Graphene oxide nanoparticles were characterized to confirm the structure, using X-ray diffraction and field-emission scanning electron microscopy. Water-based grapheme oxide nanofluids were synthesized. Three-level (3²) factorial design was used to examine the effects changes in temperature and nanoparticle loading on the thermal conductivity of prepared nanofluids. Significance of model used was tested using analysis of variance at a 95.0% confidence interval. The results revealed that thermal conductivity varies directly with temperature as well as weight concentration. 30.4% thermal conductivity enhancement is observed at optimum conditions, i.e. high level of temperature (60 °C) and medium level of weight concentration (0.1 wt%).

The chassis of automobile houses crucial mechanical component such as engine, suspension, steering and transmission system. Therefore, the chassis structure must be strong enough to absorb the static and dynamic loads generated by these mechanical components. In this work, the structural strength of go-kart chassis has been improved against static and dynamic loads through geometrical modifications. The geometrical modifications in the chassis structures were decided individually on each structural element where maximum deformation was analyzed in the modal analysis. This structural element was reanalyzed after making multiple variations in its geometry in attempt to minimize the deformation. When the minimum deformation was achieved in the structural element, then structure was finalized for stage 1. Similarly, other structural elements were also modified in the same continuous iterative process by keeping in consideration the weight constraints. After the termination of each modification torsion test, impact analysis was also carried out to examine torsional rigidity and crashworthiness. In five successive iterations, the optimum results for the chassis structure were obtained with little scope of further improvement. In the final structure, the lowest modal frequency was found to be shifted from 11.691 to 57.318 Hz to that of the initial structure. A significant reduction of 42% in maximum deformation along with a reduction in mode shapes was also witnessed in the final structure. The final structure was also found to be better in the results obtained from torsional analysis and impact testing.

In the present research work, an effort has been made to study the impact strength and water absorption ability, also the consequences, of the hybrid poly lactic acid composites prepared by using sisal and jute fibers through compression die process. The input process parameters such as compaction pressure (CP), molding temperature (MT), and curing time (CT) have been studied in the response of the observed outcomes through the application of Taguchi-based design of experimentation approach. Further, the surface morphology of the samples after impact and water absorption tests has been studied to understand the mechanism of failure. From the analysis of variance, it has been found that molding temperature (MT) acted as the most influential parameter affecting the observed properties at 95% confidence level.

Minimum quantity lubrication (MQL) is a method where cutting fluid is supplied to the machining zone in the form of droplets (10–500 ml/h). The performance of MQL machining depends on the quality of spray generated by the MQL system. The spray quality is defined by droplet diameter, velocity and the number of droplets. In the present work, computer simulations were performed to study the characteristics of spray generated with internal mixing nozzle using three different types of cutting fluids, namely vegetable oil (VO), synthetic oil (SO) and mineral oil (MO). Effects of air pressure and mass flow rate of these cutting fluids on spray formation were also studied using ANSYS FLUENT. The results showed that with increase in air pressure and mass flow rate of cutting fluids, diameter of droplets decreased, whereas velocity and number of droplets increased. It was observed that not only the spray quality generated using vegetable oil is better than other two cutting fluids, but also the surface heat transfer coefficient (HTC) improved using vegetable oil. Surface heat transfer coefficient (HTC) using vegetable oil (VO) increased by 16.28% over synthetic oil (SO) and 32.16% over mineral oil (MO).

Loading can make defect to propagate abnormally in the bearing, and in such circumstances, bearing life estimation can become a difficult task. To deal with this, it is important to understand the effect of variable loading conditions on signature characteristics and later further analysis can be made in this field. In this work, effect of variable loading was studied on vibration signature characteristics originated from defect by carrying out the statistical analysis. Two different sizes of axial groove defects present on the outer race of taper roller bearing were used for the purpose of the study with three different loading conditions in the form of additional mass on the shaft. The trend of different statistical parameters was plotted and investigated for different loading conditions. The analysis reveals that only standard deviation and Shannon entropy (SE) were showing downward trend with an increase in loading. Torsional damping of the shaft increases with an increase in weight (load) on the shaft and that may be the cause of trend shown by standard deviation and SE. To comprehend this relation, statistical analysis was also carried out on theoretically constructed signals with three different damping characteristics and on single burst with having different loading conditions. In both the analysis, same trend was observed for the parameter’s standard deviation and SE, which signifies that loading and damping are having commensurate relation. Simple sensitivity index (SSI) was calculated from the responded parameters to find the most sensitive parameter to the loading and the results revealed that SE supersedes standard deviation in dealing with loading conditions.

Composite materials are widely considered nowadays for several kinds of structural applications. In the analysis of the beam, particularly for a composite using experimental or numerical method, it is quite challenging in comparison with the regular conventional materials. Hence, in the present work, carbon fiber and glass fiber beam are considered for vibration analysis of composite beam. In the numerical modeling, three aspect ratios (i.e., L/H) in the range of 100–150 are considered with multilevel orientations (i.e., [0/0]₃, [45/90]₃, [90/0]₃ [0/0]₄, [45/90]₄, [90/0]₄). Two boundary conditions (cantilever, simply supported) are considered for the beams. From the numerical analysis, it is observed that glass fiber composite beams have a higher natural frequency in comparison to carbon fiber composite beam.

Single row taper roller bearings are basically designed to withstand the radial load, axial load, and torque which results in generation of contact stresses. Generation of contact stresses will take place due to high speeds and heavy loads on bearing that can lead to failure of machine. Bearing life is limited by some of the common phenomena like wearing, smearing, flaking, etc. Bearing life can be enhanced by proper lubrication which separates roller with inner and outer rings. As prediction and validation of contact stresses experimentally is an arduous task, many researchers calculate theoretical method for approximate distribution of contact stresses on bearing race. Some of the methods are numerical method, finite element analysis (FEA) software, traditional method, and Hertz contact stress theory. In this paper, temperature behavior distribution in the bearing, contact stress, deformation of bearing rollers, and heat flux is analyzed by FEA tool. Inner race bearing surface and ball surface contact in bearings can cause an increase in temperature which may result in evaporation of lubricant due to improper heat dissipation and effect the service life of the bearing FEA results is compared with results obtained by Hertz theory to inspect the feasibility of bearing problem and its life. It is found that temperature distribution is 55 ℃ (maximum) at the inner ring, von Mises stress is 220.23 MPa, and heat flux is 0.61399 W/mm², whereas result obtained by Hertz theory is 195.2821 MPa. Compariosn of FEA and analytical result, the error is found to be 12.77% analysis of increase in temperature through FEA is a useful tool for estimating the service life of bearings.

Rolling element bearings are extensively used in machinery to transmit rolling/sliding motion. These machine elements are prone to get damaged due to an increase in friction, which causes the heat generation and gradual wear on rolling contact surfaces of the bearing. Bearing failure leads to an unexpected shutdown of machinery. Therefore, many condition monitoring methods have been developed to predict bearing faults. The ultrasonic flaw detection method is one of the promising techniques to detect bearing faults. This paper describes the application of ultrasonic to detect incipient faults developed in the roller bearing subjected to fatigue load cycles. Results highlighted the suitability of the ultrasonic method to identify the incipient faults that appeared on the rolling contact surfaces.

Postural inaccuracies in persistent dental tasks indicated an upsurge in the prevalence of musculoskeletal disorders in dentists. The study assessed the angle parameters related to the bodily movement of upper arm (UA), lower arm (LA), wrist (W), neck (N), and trunk (T) using self-developed markerless Kinect V2 system and conventional imaging technique. Ten dentists were monitored with both techniques while performing real-time dental procedure. The agreement between the techniques was assessed using Bland–Altman at 95% bias, Pearson and concordance correlation coefficients (r1 and r2), mean difference, and percentage error. For conclusive agreement analysis, contingency coefficient (C), proportion agreement index (Po), Cohen’s kappa (k), and Mann–Whitney at 95% confidence interval were evaluated. Data from both techniques possessed strong correlations (r1 and r2 > 0.90). Cohen’s kappa (0.67) at standard Landis and Koch scale showed good agreement in RULA data. Postural analysis of slow-motion tasks like dentistry using Kinect V2 system proved as unobtrusive and efficient. This may be used by dentists to have periodic postural check.