Modelling the Effects of Friction on Tool-Chip Interface Temperature During Orthogonal Cutting of Al6061-T6 Aluminium Alloy

© IEOM Society International - IEOM 2019In this work, finite element simulations based on the analytical model derived with the MATLAB software were used to establish the temperature fields within the cutting tool and tool-chip interface. The average tool-chip interface temperature model was simulated and the simulation results were compared with experimental results for validation. At a maximum cutting speed of 90 m/min, the maximum temperature obtained from the experiment was 410 oC, at same rake angle of 0o. However, the developed model predicted 490 oC under the same conditions. The higher value obtained by the model can be attributed to the negligence of heat losses to the surrounding by both convection and radiation modes, as an assumption in the formulated model. A similar trend of these results was also recorded for the case of rake angle and feed rate of 30o and 0.0635 mm/rev, respectively. It was observed that the simulation results and experimental measurements for the average tool-chip interface temperature agreed significantly.Final Published versio

Development of a Cashew Nut Cracking Device

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Development of a Cashew Nut Cracking Device. Manuscript PM 06 030. Vol. IX. June, 2007

EXPERIMENTAL PREDICTION AND OPTIMIZATION OF MATERIAL REMOVAL RATE DURING HARD TURNING OF AUSTENITIC 304L STAINLESS STEEL

This work involves a predictive model for material removal rate (MRR). It investigates the influence of machining process parameters such as cutting speed, feed rate and depth of cut on the material removal rate (output parameter) during hard turning of AISI 304L austenitic stainless steel (0.03 wt. % C (max)). A total of 27 experiments were conducted using a MORISEIKI SL-253B CNC machine with cemented carbide cutting tool under three different spindle speeds (1000, 1200, 1400rev/min), feed rates (0.05, 0.10, 0.15mm/rev) and depths of cut (0.4, 0.8, 1.2mm). The machining parameter settings were determined using the Taguchi experimental design method. The Taguchi method and relationship between MRR and input parameters were arrived at through MINITAB16 software package. The optimum machining parameters combination was obtained by using larger-the-better analysis of signal-to-noise (S/N) ratio. The optimal cutting condition is at spindle speed level 2 (1200 rpm); feed rate at level 3 (0.15mm/rev) and Depth of cut at level 3 (1.2 mm) which gave an optimum MRR of 77.80243mm3/min. The S/N ratio response table, main effect plots and the relationship between cutting parameters and the MRR was obtained. A mathematical model was developed using multiple regression analysis to predict MRR during hard turning of AISI 304L austenitic stainless steel. The level of importance and performance characteristics of the machining parameters on MRR was determined by using analysis of variance (ANOVA). From the results, the feed rate had the most significant effects on the MRR followed by depth of cut.The spindle speed has the least effect on MRR. It was also revealed that the predicted results found a good correlation with the experimental results as the regression line fits well for both results data at 95% confidence interval.Keywords: Machining; material removal; optimizatio

Using frequency domain analysis techniques for diagnosis of planetary bearing defect in a CH-46E helicopter aft gearbox

© 2018 Elsevier Ltd Condition monitoring for helicopters has always been one of the most critical technologies to guarantee the integrity of the rotorcrafts, enhance operational and personnel safety, and reduce the overall maintenance costs. Over the past decades, health and usage monitoring system (HUMS) has been developed and implemented in helicopters to monitor the health status for the main gearbox (MGB) and other key components of the transmission system, improving condition-based maintenance for helicopters. However, many studies have indicated that current HUMS has a limited sensitivity to MGB planetary bearing defects. To enhance HUMS’ performance, this paper presents an approach based on frequency domain analysis techniques to diagnose planetary bearing defects using real helicopter data collected from a CH-46E helicopter aft MGB. Vibration data was processed using signal processing techniques including self-adaptive noise cancellation (SANC), discrete-random separation (DRS), cepstrum editing, kurtogram, envelope analysis and iterative envelope cancellation. Processing results conclude that frequency domain analysis techniques can provide distinct and intuitive indications of the seeded defects at both the inner race and the outer race of the faulty planetary bearing

EXPERIMENTAL AND THEORETICAL INVESTIGATION OF TENSILE STRESS DISTRIBUTION DURING ALUMINIUM WIRE DRAWING

Wire drawing, has received a wide range of applications in the production. A wide number of cable applications demand that the cable survive high tensile loading. This works entails experimental and theoretical investigation of tensile stress distribution during aluminium wire drawing. The initial Aluminium rod used in this work was, 9.50mm with density of 2700kg/m3 , young’s modulus of (7x1010 Pa), Poisson’s ratio (0.33), Yield stress in simple tension (21.7 × 106Pa), which was later drawn to different diameter as required and tensile testing was carried out on each required diameter. In this work, tensile stress distribution in the drawing process is determined via experimental and analytical method. A free body equilibrium method is used to obtain the equations that dictate the drawing phenomenon. The result obtained by experiment is compared with improved model and also with other solutions found in the literature about these themes, particularly, with Rogas solutions in slab method case. There is high degree of similarity between the result obtained experimentally and the simulation of improved model but there is a wide gap when compared experimental result with simulation of classical slab method. Thus, the result of the study will be of great benefit to industries that make use of aluminium wire as electrical wiring, cables, spokes for wheels, stringed musical instruments, paper clips and tension-loaded structural components and also automotive sector. This will help them determining the extent of tensile loading that the aluminium wires their working on can withstand before failure can occur

Rollover Stability Models for Three-Wheeled Vehicle Design

The current commercial  three-wheeled vehicles (TWVs) in the market are rollover unstable, with adverse effects on life and property.  This places limitation on their speed and usage, even though they are fuel efficient, cheap and generate about 33% of green gases per rider when compared with four-wheeled vehicles.This work derived mathematical models for the analysis of the stability of the three-wheeled vehicle (TWV). Based on these models, the test method for rollover stability was adopted. Rollover test was carried out on a TWV on Nigerian road. The results showed that the vehicle is unstable with respect to rollover stability. The test procedure if adopted and legislated upon, would significantly enhance safety of life and property of the population. Moreover, the speed and usage of the vehicle for both private and commercial purposes will be enhanced

Analytical Investigations of Kinetic and Heat Transfer in Slow Pyrolysis of a Biomass Particle

The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a USAble form of energy,pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be “analytically involved” showed average percentageerror and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers

Mathematical Modelling of Leachate Production from Waste Contained Site

In this work, mathematical models of leachate production from Waste Contained Site (WCS) was developed and validated using the existing experimental data with aid of MATLAB, 2007a. When the leachate generation potentials (Lo) were 100m3, 80m3 and 50m3, the maximum amount of leachate generated were about 2920m3, 2338m3 and 1461m3 for about 130 days respectively. It was noted that as the leachate percolates through a selected distance, the concentration keeps decreasing for one dimensional flow in all the cases considered. Decreasing in concentration continues until a point was reached when the concentration was almost zero and later constant. The effects of diffusivity, amount of organic content present within the waste and gravity, as cases, were also considered in various occasions during the percolation. Comparison of their effects was also taken into account. In case of gravity at constant diffusivity, decrease in concentration was not rapid but gradually while much organic content in the waste caused the rate of leachate production to be rapid; hence, giving rise to a sharp sloped curve. It can be concluded that gravity influences the rate of change in the concentration of the leachate generation as the leachate percolate downward to the underground water. When the diffusivity and gravity are put into consideration, the concentration of the leachate decreases gradually and slowly

Theoretical Determination of Temperature Field in Orthogonal Machining

In this work, mathematical models were developed to simulate the thermal behaviour of a cutting tool insert in three-dimensional dry machining. Models to determine the temperature rise at the shear plane and tool insert in orthogonal cutting were developed, simulated and validated. The effects of various machining parameters/variables such as specific heat of material of 4400J/kg, Depth of cut (t) of 0.0003m, Density of 7870kg/m3, Width of cut (b) of 0.005m, Chip thickness ratio (rt) of 0.42, Tool rake angle of 100, Cutting Velocity (V) of 35m/min and Shear force (Fs) of 1257.6N on temperature rise were well analyzed

Using Frequency Domain Analysis Techniques for Diagnosis of Planetary Bearing Defect in a CH-46E Helicopter Aft Gearbox

Condition monitoring for helicopters has always been one of the most critical technologies to guarantee the integrity of the rotorcrafts, enhance operational and personnel safety, and reduce the overall maintenance costs. Over the past decades, health and usage monitoring system (HUMS) has been developed and implemented in helicopters to monitor the health status for the main gearbox (MGB) and other key components of the transmission system, improving condition-based maintenance for helicopters. However, many studies have indicated that current HUMS has a limited sensitivity to MGB planetary bearing defects. To enhance HUMS’ performance, this paper presents an approach based on frequency domain analysis techniques to diagnose planetary bearing defects using real helicopter data collected from a CH-46E helicopter aft MGB. Vibration data was processed using signal processing techniques including self-adaptive noise cancellation (SANC), discrete-random separation (DRS), cepstrum editing, kurtogram, envelope analysis and iterative envelope cancellation. Processing results conclude that frequency domain analysis techniques can provide distinct and intuitive indications of the seeded defects at both the inner race and the outer race of the faulty planetary bearing