Engineering Headway Vol. 4

Abstract: Nickel superalloys are being used in applications subjected due to its excellent creep and oxidation behavior. The CM247LC nickel based super alloy is considered due to its exceptional combination of high-temperature strength, creep resistance, oxidation/corrosion resistance, and mechanical properties suitable for applications, particularly in the aerospace industry. Though, unfavorable tribological behavior is primary challenge in gas turbine applications. Nickel-based superalloy CM-247LC was manufactured through laser powder bed fusion process under two different conditions. X-ray diffraction analysis (XRD) was carried out to study phases present in as built CM247LC alloy. Microhardness and tribological characteristics were investigated on the as built alloy. XRD spectrum was predominantly observed with γ and γ′ peaks. Presence of γ′ and MC carbides offered strengthening to the as built CM247LC alloy which enhanced the hardness and tribological properties. The wear rate of samples gets increased with increase in load applied during the wear test. Worn out surfaces were examined and it is observed that the predominant type of wear mechanisms as adhesion and abrasion.

Abstract: The solidification mechanism of ductile iron is a bit complex due to the precipitation of graphite and silicon. These elements change the solidification pattern of cast iron. Density of these elements is less than iron leads to occupying more volume consequently increase the overall metal volume. There are two aspects on this increase in metal volume. One is, reducing this volume increase to reduce the creation of porosities at the earlier stage of solidification and second is, using this volume increase to remove porosity at the later stage of solidification. Proper understanding of this graphite expansion in cast iron solidification will bring insights on reducing or removing of the risers. The current study focus on correlating the net contraction and austenitic liquidus point with shrinkage. The average contraction found through this study is 1.36 % which is more than the net expansion of 0.25 % (without riser) reported in literature.

Abstract: In this paper, the effect of heat treatment temperature on the resultant composition of composite Al-Si coatings on ZK60A alloy investigated. The coatings were developed using magnetron sputtering deposition. These coatings can serve as an effective anti-corrosion barrier for Mg alloys in aqueous mediums. The magnetron target composition was 80% Al and 20% Si, while in the deposited coating it was 78% Al and 18% Si, with the rest being atoms from the substrate. The as-deposited coatings had pores and the Al-Si composite was deposited in the form of globules. The sputtered coatings were subjected to heat treatment for 1.5 hours at 420 °C (HT1) and 350 °C (HT2). The ratio of elements in the heat-treated coatings changed significantly due to diffusion between substrate-coating interface and migration through the pores that exist in the coating. It was found that Mg migrates into the coating and Si into the substrate. Al/Mg ratio reduced by 81.2 and 60.6 %, respectively, in the coating after the HT1 and HT2.

Abstract: Measurement of strain and stress plays a crucial role in advancing research in mechanical engineering. In this paper, the bending strain and stress of the steel cantilever beam subjected to concentrated loads at the free end are investigated using analytical, experimental, and numerical approaches. The experimental investigation was carried out through the use of a strain gauge sensor connected with a Wheatstone quarter-bridge configuration. The strain gauge used in this experiment is interfaced with the NI SignalExpress software in conjunction with the NI modules to ensure accurate data acquisition. The experimental measurements provide essential benchmark values for comparison with the numerical results. The numerical simulation is developed using ANSYS Workbench. The comparison results show that the experimental values have good agreement with the simulated FEM and analytical values. The findings of this study provide valuable insights into the bending strain characteristics of steel cantilever beams and contribute to the advancement of mechanical engineering research.

Abstract: Commercial tyres that are specifically designed for higher speed and on-highway tarred road conditions are currently being used on lightweight underground mining utility vehicles. This is due to there being no alternative tyres that are readily available to better suite the application and environment. This research calls attention to the side effects of using commercial tyres in mining environments. As a result, a model-based systems engineering approach is used to design a more appropriate tyre for this environment. Airless tires have been a focus area for many top tyre manufacturing companies however the criteria and focus of existing papers has predominantly been on commercial tyres that follow a completely different set of design rules and requirements. In this research a topologically optimised tyre that better conforms with the design parameters of the vehicle, is proposed and analysed. A computational aided design (CAD) model of a commercial pneumatic tyre and a foam filled tyre was created. Data from a typical mining vehicle of this class was captured and used to calculate the mechanics as inputs to the finite element model (FEM) including driveshaft effects. This model is then statically analyses and optimised over various iterations of topologies. The iteration stopping criteria is reduced stresses on drivetrain components and being able to accommodate a greater payload. This research provides a proof of concept on the feasibly of replacing standard commercial pneumatic or foam filled tyres with purpose designed airless tyres to better serve the mining market whilst retaining original equipment manufacturer vehicle design parameters. From the results it was found that these tyres can meet the loading requirements as specified given the resultant deflections, reduced stresses and reduced polar second moment area on the driveshaft component (s).

Abstract: The time-dependent magnetohydrodynamic (MHD) Couette flow of Maxwell material in a rotating system with ramped wall temperature has been examined under Ohmic (Joule) heating. The Continuity equation, Cauchy’s equation of motion, the constitutive equation for the Maxwell model, and the energy equation with Ohmic heating with relevant initial and boundary conditions are all considered in obtaining a mathematical model for the investigation. The finite element technique is applied to numerically solve the non-dimensionalized governing equations using the mathematical software MATLAB. The values of Weissenberg number, Hartmann number, Eckert number, and angular velocity of the rotating system are varied, and their effects on the fluid temperature and velocity are shown graphically and discussed.

Abstract: In this study an Artificial Neural Network for the simulation of flood phenomena in a natural area was developed. Then this network was implemented in the urban area of a Greek city (Amyntaio, Florina). The neural networks have many advantages: non-linearity, adaptability, input-output mapping, indicative response, damage resistance, possibility of implementation with VLSI (Very Large Scale Integration) technology, content related information and analysis and design uniformity. With neural networks, mathematical simulation of the considered phenomenon is not attempted, but the extraction of quantitative conclusions for specific data, based on similar cases. With the development and implementation of this network all the points that are in risk for flood are identified. The results showed that the help of an Artificial Neural Network in these cases is crucial for the future decisions in cases of flood phenomena.