Mechanical Engineering

The combination of Casting and Powder Metallurgy can promote refined and more uniform microstructures which can result in improved properties and higher isotropy of material. The potential of such blending can be studied by using three important processes viz. Osprey Process, Ceracon Process and Slip Casting Process. These processes can be compared on the basis of microstructure, Austenitizing temperature, and Hardness with Scanning electron microscopy and can be related with conventional processes of manufacturing.

A four stroke spark ignition engine is a mechanical engine in which its operation completes by four strokes or movements of piston in the engine cylinder. This engine can also be called gasoline or petrol engine because its basic fuel is gasoline but nowadays, alternative fuels are being considered as the engine operating fuel. The alternative can be mixture of gasoline with other hydrocarbon products like ethanol or singly be another hydrocarbon product that can offer a better performance and lesser consumption when compared with gasoline. Though, the alternative fuels offer lesser consumption but it can also be intensified by considering the engine design specification for better performance which led to the birth of this work. Compression ratio of the engine determines the engine performance, the higher the compression ratio, the greater the efficiency of a spark ignition engine. In ordinary gasoline fuel, higher compression ratio can infer another engine problem like knocking and emission of toxic combustion product but the alternative fuels have been developed to lessen all these effects. The aim of this work was to simulate the influence of compression ratio on an alternative fueled four-stroke spark ignition engine using C# computer program. The simulation model was carried out under assumed varying compression ratio; 4.63, 5.10, 6.00, 6.88, 7.40, 8.28, 9.16, 9.94, 10.45, 10.98 and 11.44, from this, the volume relationship was determined. The mathematical engine simulation model was carried out using thermodynamics-based models. The result of the simulation showed that higher compression gives higher efficiency and the numerical values are in close agreement with experimental values. The percentage error is not more that 2% during combustion duration and efficiency as compared with experimental values. From the numerical results, it was observed that if the compression ratio is high, the crank angle will also be high and this will make the ignition delay period to be diminished. This also goes for the engine performance, power output or the efficiency, the higher the compression ratio the greater the efficiency. Therefore, an alternative fueled engine with compression ratio of 9.16 and above will have a greater efficiency.

Laser machining operation is a thermal, separation process, well suitable for several engineering industrial applications. High cutting speed, superior cut quality and low machining costs made laser cutting to become competitive to existing methods of contour cutting. Austenitic stainless steel is a significant engineering metal and it is complex to cut by oxy–fuel formed oxides and high melting point. So, austenitic stainless steel is mostly appropriate to be cut by laser. The cutting process parameters are highly affects the laser cut quality. In this research 1.9 mm austenitic stainless steel is cut with co2 laser. Laser power, cutting speed, gas pressure and focal distance are to be varied. The goal of this research is to narrate these conditions to formations of burr and surface roughness of cut edge. These relationships are engendered and approved with a mathematical model, which is used to forecast and reduce burr height and minimizing the cut edge surface roughness.

In this paper, the composite laminates were fabricated to different weight percentage of uni-directional and stitched cross mat E-glass fibers, glass and Kevlar fiber reinforced with epoxy resins and hardener. For laminates fabrication epoxy matrix is maintained is constant weight percentage (60%) and glass fibers with different stacking sequences is added with various weight percentage. Mechanical behaviour of composites such as tensile property, flexural property & impact resistance are study in this investigation. The various geometry of E-Glass/Kevlar fiber reinforced laminates manufactured by hand lay-up method and followed by compression moulding technique. Where epoxy is constant (60%) and change the fiber percentage, specimens prepared with difference stacking sequences material are tested. The results show tensile strength and impact resistance are high to the stitched cross glass(SCM) fiber mat(40% ) .The flexural strength and natural frequency is high in order to Chopped strand (CSM) mat(10%)/Kevlar(K) fiber(30%), CSM(30%)/K(10%).

Instrumented cadaveric knees were used to address the interaction between unopposed quadriceps muscle forces (QMF), ground reaction force (GRF), and strain in anterior cruciate ligament (ACL) through in-vitro simulation of a vertical jump-landing process. The objective of this research was to evaluate the effect of unopposed QMF, low knee flexion angle, joint conformity and constant GRF on the ACL strain. Fourteen cadaveric knees were mounted in a custom made dynamic loading simulator. The strain on the anteromedial bundle of the ACL was measured using a Differential Variable Reluctance Transducers (DVRT) sensor. Also, an I-Scan pressure transducer was used to measure the contact pressure and area in the tibiofemoral joint. During landing phase, the peak pressure on the lateral compartment is very high compared with the medial compartment. During landing phase, both the contact area and pressure increases in the tibiofemoral joint. The induced joint conformity caused by contact pressure has been justified. The results show that unopposed quadriceps muscle forces coupled with ground reaction force at low knee flexion angle cannot cause ACL injury. Joint compressive loads induced by large muscle forces and GRF introduces the joint conformity, and it produces the primary restraint against anterior tibial translation at low flexion angles.

A Study on moisture management properties for Polyester with Bamboo Biply knitted fabrics has been reported. The polyester (80 D), Bamboo yarn (30s and 40s Ne) were selected to produce the Biply rib knitted fabrics with various areal density, thickness and tightness factors to analyze the moisture management properties of fabrics. It was observed that polyester with bamboo Biply knitted fabrics have higher air permeability than the polyester with cotton Biply knitted fabric. It is also observed that there is a significant difference between water vapour permeability of polyester with bamboo and polyester with cotton Biply knitted fabrics. It is also found that the polyester with bamboo knitted fabric has better wicking rate than the polyester with cotton Biply knitted fabrics. This Polyester with Bamboo Biply knitted fabrics materials can be used to prepare the composite materials.

The combustion process in Internal Combustion engines is greatly influenced by the fuel injected into the chamber and its interaction with the air. Investigation of which involves analyzing injection process from the structure point of view of the fuel spray. In addition, optimizing the spray conditions is highly important in reducing the exhaust emissions and improving the performance and combustion characteristics. The main objective is to optimize various parameters of spray for different blends of biodiesel and injection pressure mainly with respect to Sauter Mean Diameter (SMD), spray tip penetration and spray cone angle using concept of Taguchi and also identifying its contribution using analysis of variance commonly known as ANOVA with the help of ?Minitab 14.0? software where the optimum levels of parameters were found using higher Signal - Noise ratio. Based on the number of trials of experiments, spray images of biodiesel for the different combination of control factors were captured and analyzed. Furthermore performance, emission and combustion characteristics are compared by advancing as well as retarding the injection timing in existing Compression Ignition engine for the optimum condition obtained from the experiments conducted in spray chamber. The higher brake thermal efficiency is attained when it is retarded may be due to lower fuel consumption. Unburned hydro carbon is lower for KB20 due to unstable nature and simple molecular structure. Further, among all the blends KB20 can be considered to the best blend on the basis of spray characteristics.

An extensive review conducted before this study, showed data limitation is the main constrain for multiple regression approach. Thus, new technique has been innovated through bit wear distribution over drilled interval depends on formation fingerprint. Field geological, drilling and logging data collected from three wells located in Blue Nile basin subjected to considerable concentrated analysis. Drilling rate predicted as a function of optimum weight on bit and rotation per minute using Bourgoyne and Young model. The Unknown Bourgoyne and Young coefficients have been determined. Correlations of multiple regressions using Statistica-12.5 software predict acceptable values of nine unknown coefficients. Hypothesis test of predicted coefficients showed over 95% confidence interval which simulated saving in time of drilling by 25%. Out comes was verified through Payzone drilling simulator via simulating actual field observations and re-simulate predicted ROP values. Results revealed the proficiency of predicted drilling rate values. The rate of penetration general equation constructed for each formation; then graphs produced for each formation individually depends on bit type and operational conditions.The methodology and out comes presented in this paper enable prediction of optimum penetration rates directly through accurately produced graphs that is during the well planning period for next wells to be drilled in Blue Nile Basin or other similar formations. This research offers new technique via distribution of drill bits dullness over drilled interval to overcome data limitation constrain. Together with qualitative and quantitative analysis of the optimized results that revealed high potentiality of new technique through both operation and economic benefits on drilling.

The phase change process for energy storage is a complex heat transfer phenomenon and the solidification and melting process make the charging and discharging process entirely a transient heat transfer process. Analytical solutions are not available to evaluate the temperature of the PCM during the charging and discharging process. Hence, numerical methods are to be adopted to solve the governing equations involved during this transient heat transfer phenomenon. Further, the correlations are developed using the results obtained from the regression analysis using the experimental results to provide simple solutions to the practicing engineers. In this study, heat transfer experiments were conducted under different levels of air flow rate, inlet temperature, charging and discharging time according to the central composite rotatable design matrix. Within the design space, heat transfer variables were optimized using response surface methodology (RSM) concept to the required PCM melting temperature and room temperature. Further, optimized results show that the minimum PCM melting temperature of 29.8 ºC and room temperature of 28.6 ºC are obtained at the mass flow rate of 0.06 kg/s, inlet temperature of 31.4 ºC, and discharging time 86 mins by optimizing process parameters.

The fiber reinforced laminate composite plates, because of its outstanding mechanical properties such as high strength, high stiffness with less weight, durability, corrosion resistance, finds many engineering applications. In this work, local failure of plate alone in-between the stiffeners is taken for study. This work compares the buckling behavior of thin fiber reinforced laminate composite plates subjected to axial compression under different types of boundary conditions with different types and different angle of layups. For this purpose graphite / epoxy composite rectangular plate is used for the analysis. Further, by varying the dimension of plate, effect of the aspect ratio of the plate on the buckling strength of plate is also studied. Eigen buckling analysis of ANSYS is used for analysis.