Structural Strength of Cemented Carbides

The concept “structural strength of tool materials” got further development. The refusals of cemented carbide cutting plates, when heavy machining were analyzed. It was shown that 70…80% of refusals are the microchipping of cutting edges, tool cutting part chipping, cutting plate macrofracture. To assess cutting plate total carrying capacity and the influence of different methods of cemented carbides modification, bending tests were held. Local fracture resistance and damageability of cutting edge were assessed under its continuous scanning.

Fuzzy Prognosis System for Decision Making to Vibrations Monitoring in Gas Turbine

This paper proposes a decision making approach based on the development of a fuzzy prognostic system to ensure the vibrations monitoring of a gas turbine based on real time information obtained from different installed sensors. In this approach the case of incomplete obtained data which may occur frequently is taken into account by using an approach of full data reconstitution form incomplete data. The proposed fuzzy prognostic system approach presented in this paper allows the analysis of the data obtained via the vibration indicators of a gas turbine system for the accurate identification of the faults to avoid the performance degradation of such systems. In order to prove the robustness of the proposed approach presented in this paper, several tested has been performed.

The Mechanical Properties and Fatigue Prediction of a New Generation of Osteosynthesis Devices

The aim of the study was to predict the fatigue life of metallic bone plates employing SIMULIA fe-safe software. Two materials commonly used for surgical implants were subjected to investigation: 1.4441 (ASTM F138) stainless steel for implants and Ti6Al4V ELI (ASTM F136) titanium alloy. The material parameters of the two materials were determined from experimental research. Four-point bending fatigue testing was conducted on two generations of bone plates in order to allow for the comparison of the prediction results with the measured data from the experiments.

Correction Factors for Determining the Mass Transfer Coefficients

A number of industrial operations are linked to mass transfer. The mass transfer coefficient value is necessary to know when designing the industrial equipment in which mass transfer occurs. There are various mass transfer coefficients, as well as equations for their calculation. However, the value of these coefficients determined according to these equations often has to be corrected for the given conditions. The aim of the article is to state the conversion relations - the correction factors enabling the calculation of the mass transfer coefficients values corresponding to the given conditions.

Application of EDAS, MARCOS, TOPSIS, MOORA and PIV Methods for Multi-Criteria Decision Making in Milling Process

Low surface roughness and high Material Removal Rate (MRR) are expected in most machining methods in general and milling method in particular. However, they sometimes do not occur, for example, the MRR is often small as the surface roughness is low. In this case, the decisions made should ensure that desires are simultaneously satisfied. This situation leads to a problem known as multi-criteria decision making (MCDM). In this study, five methods including EDAS, MARCOS, PIV, MOORA and TOPSIS are used together for the decision-making in the milling process. The purpose of the research is to determine the value of cutting parameters for both the low surface roughness and large MRR. The comparison of these methods for finding the best is carefully discussed as well.

Assessment on the Optimum Performance of a Novel 3 Axes Micro EDM Developed for Commercial Applications

A low cost three axes commercial microEDM machine has been developed indigenously in order to implement precision micromachining. The developed microEDM consists of various components such as machining chamber, X-Y table, tool feed and tool holder assembly, dielectric circulation system, power supply and automatic driving devices to control the spark gap distance. The setup is capable of performing the 8µm movement in Z-axis.The developed 3 axes machine and the commercial available machine are investigated with the most important process parameters such as Current, Pulse on time and Pulse off time in order to study the Material Removal Rate (MRR) and Tool Wear Rate (TWR). The material chosen for the current research is Stainless Steel 316L, which has high corrosion resistance and the electrode was tungsten 300µm. In most of the experiments, the developed machine has performed with 6.52% higher MRR and 26.10% Lower TWR. This is due to the effective spark gap circuit developed with the use of hall current sensor.The mathematical model of MRR and TWR are obtained by correlating the process parameter using Response Surface Methodology (RSM).The chosen objectives are contradictory in nature, we employ a non-dominated Genetic algorithm to find the optimal process parameters. The developed 3 axes microEDM has yield a 10.14% and 33.12% better performance on optimum maximum MRR and minimum TWR respectively when compared to the commercial machine.

Effect of Selected Components on Combustion of Methane

Article discusses the effect of various gases on the combustion of methane in LGW 702 combustion engine intended for use in cogeneration unit. The measured results were evaluated for internal, performance and economic parameters of the combustion engine the ideal operating parameters can be set. The aim of the study was to assess the effect of combustible carbon monoxide and carbon dioxide and nitrogen on the parameters.

Optimization of Drilling Parameters During Machining of Al-Mg-Si Alloys By Taguchi Method Coupled with Grey Relational Analysis and Validated By Fea Based Deform - 3D

In the present work to validate the experimental results as per Taguchi based grey relational analysis by considering L27 orthogonal array corresponding to five factors with three levels and obtained optimal combination of input parameters to minimize the output responses during drilling process which is most important finishing operation required in the structural assembly works where we found application of Al-Mg-Si alloys, Deform-3D software is implemented and found good feasibility with that of experimental results.

Determination of Bearing Quality Using Frequency Vibration Analysis

The paper proposes two methods for determining the quality of industrially manufactured bearings, where the vibro-acoustic energy is expressed by measuring the vibration acceleration. The determined criteria were verified and 100 % agreement was reached in determining the required quality of the bearings. Unwanted bearing noise emissions and its faults can be monitored over the maximum acceleration value determined from the time history, the frequency distribution and the r.m.s. value of the determined frequency range.

Hydrodynamic Performance of the 3D Hydrofoil at the Coupled Oscillating Heave and Pitch Motions

The purpose of this paper is to study on the power extraction of the hydrofoil by performance of the coupled oscillating heave and pitch motions. The numerical analysis is conducted by using the Reynolds Average Navier-Stokes (RANS) equations and the realizable k- ɛ turbulent model of the Star-CCM+ software. A 3D oscillating hydrofoil of NACA0015 section with aspect ratio of 7 is selected for the present analysis at two inflow velocities and three frequencies. The numerical results of lift and drag coefficients, horizontal and vertical forces coefficients, power efficiency in time domain and average value of those parameters are presented and discussed. According to the numerical results, the high efficiency of hydrofoil is found at the reduced frequency of 0.18 and the flow velocity of 1 m/s and the low efficiency is obtained at the reduction frequency of 0.06 and the flow velocity of 2 m/s. Moreover, the contour results of vorticity, streamline and pressure distribution are also presented and discussed. The computational model depicts clear vortex patterns surrounding the hydrofoil, which has a major impact on the power performance of oscillating hydrofoil.