Papers by Keyword: Torque

Abstract: In terms of machinability are titanium alloys classified in the group of difficult to cut materials. The main factors determining this status are limited tool life, high generated cutting forces (torque) and temperature in cutting zone caused by low thermal conductivity as well as chemical reactivity with cutting tool. Solid carbide drills still remain as preferred choice in hole making process when machining Ti6Al4V alloy. Besides cutting conditions, tool and cutting edge geometry significantly affect the value of torque. Reduction of process energy requirements can be achieved by appropriate optimization of these parameters. Mathematical model describing influence of cutting speed, feed rate, clearance angle and cutting edge radius on investigated variable with high reliability coefficient (R²=96.72%) was found. Drilling experiments were designed and carried out using Taguchi orthogonal array L₁₆.

Abstract: Drilling is the most used machining process in the assemble of Glass/epoxy composites. Material removing leads to damage and delamination in the drilling process. The present paper deals the effect of drill wt.% of multi walled carbon nanotubes (MWCNTs) on the drilling of glass/epoxy composites in term of torque and push-out delamination. Glass/epoxy composites manufactured by using pre-preg method. The filled rates were considered as 0.5, 1 and 2 wt.%. MWCNTs. Also, the unfilled composite samples were used for comparison. Various cutting speeds (40, 50 and 60 m/min) and feed rates (0.075, 0.1 and 0,125 mm/rev) for coated drills were used. The experimental result showed that the machinability properties of glass/epoxy composites samples can be improved with filling MWCNTs. Higher cutting speed and feed rate increase delamination. Push-out more severe than that of peel-up delamination.

Abstract: Numerical estimation of rolling load and torque often showed large discrepancies when compared with experimental values. This was attributed to difficulty in estimating the mean rolling temperature from the available data. This work is thus directed at obtaining a good estimate for the mean rolling temperature which can effectively be used for load and torque estimates. Hot flat rolling stimulation by use of the Bland and Ford’s cold rolling (HRBF) theory confirmed the reverse sandwich effect in selected carbon steels at low strain rates. In this work, the effect of pass reduction on rolling temperature distribution, yield stress and rolling load were studied for AISI Type 316 stainless steel (HSCSS316). For this new simulation, at low and high strain rates, results showed that the ratio of experimental to calculated rolling load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HSCSS316 low reductions. The results obtained from Hot Rolling Bland and Ford’s Theory based on Root Mean Square rolling temperature were in good agreement with values obtained using Reverse Sandwich Model and the Reverse Sandwich- Hot Rolling Bland and Ford’s Program under the same rolling conditions.

Abstract: The analysis of the sliding contact behavior for friction lining is an important issue in design of centrifugal clutches. In this study, a numerical model based on the moment equilibrium and contact mechanics has been developed to analyze the dynamics of a commercial centrifugal clutch. The proposed dynamic model can estimate the rotational speed of initial contact, output torque, and contact pressure for friction lining during the clutch operation. The comparison of the numerical and experimental results for the output torque of the analyzed centrifugal clutch shows the simulation agrees well with the experimental data. The difference for the maximum output torque is around 1.9%, which shows the effectiveness of the proposed method. The proposed dynamic model can reduce unnecessary physical prototypes and experimental cost, and is expected to be used to improve the design of the centrifugal clutches.

Abstract: Glass Fiber Reinforced Polymer (GFRP) composites are being used to replace metallic materials in a wide range of industries. In the drilling of GFRP, the quality of hole is strongly dependent on process parameters. The aim of this work is to investigate the effect of cutting speed and drill material on thrust force and torque in drilling of GFRP. Drilling tests were carried out using HSS and tipped carbide twist drills and damage development during drilling was studied. The critical thrust for Iso-phthalic glass composite was found to be 60 N.

Abstract: Use of fluidized bed combustion fly ash as an admixture for manufacture of cement based composite materials is not quite common now, however, there are real ways of utilizing its potential. The most important negative feature of this fly ash is its variable chemical composition, which supports formation of new forms growing within the structure with negative impact of durability of the composite material. The morphology of this type of fly ash is also not very favorable as it has negative influence on consistency. Fluidized bed combustion fly ash considerably deteriorates consistency of cement mixture, which results in higher water-cement ratio and consequently worsening of physico-mechanical and durability parameters of the whole composite. Therefore the question arises how to eliminate this negative influence on consistency without the necessity of increasing water cement ratio.

Abstract: The depletion of fossil fuel resource is creating demand for new renewable energy resources. An experimental study was conducted in order to determine effects of various fuel blends including small amount of ethanol, naphthalene and palm oil in petrol on a single cylinder spark ignition engine. Engine performance and fuel consumption were investigated using an engine dynamometer with various loads and engine speed. Engine performance was obtained by recording the engine torque during low, medium and high engine speed from 1200 rpm - 4700 rpm. Fuel consumption of the blends was determined by the brake specific fuel consumption. Palm oil showed about 50% reduction in engine torque for the blends of 3 % and 5 %, while naphthalene showed about 11% reduction for the engine torque when the engine speed is more than 4000 rpm. Ethanol showed a slight improvement of about 1% in engine torque. 20% of ethanol blending fuel gave out the best result in terms of torque. Besides, 20% of ethanol blend found to be decreased in fuel consumption for about 9% when running at 2500 rpm in comparison with 100% petrol.

Abstract: Based on the understanding of Friction Stir Welding (FSW) and the effect of ultrasound, the purpose of the paper is trying to find the effective access to reduce the welding resistance and improve the quality of weld during FSW. The best vibration point was first determined through the vibration test system. Then, the thermal cycling, three-force and torque were tested by using paperless recorder and mechanical sensor in heat-power test bench for 4mm thick AZ31 magnesium alloy. The results showed that the periodic vibration took place at the weld under the excitation of ultrasonic vibration, and the frequency of this vibration was as same as the frequency of ultrasonic vibration. The best tracking distance of ultrasonic vibration was 40 mm, and its optimal incident angle was 45°. By applying ultrasonic vibration to FSW, the forward resistance, the axial force and the torque of the tool can be significantly reduced. In addition, the distribution of temperature field was basically consistent with the two conditions, presenting “asymmetrical, non-linear” distribution characteristic. The heating effect of ultrasonic vibration was not obvious, but it was able to make the temperature field of the welding seam become more uniform.

Abstract: Abrupt breakage of the taps is frequently encountered during tapping threads, especially when tapping on ‘difficult-to-cut’ material like titanium. This work therefore presents an extensive experimentation with the Taguchi approach to investigate maximum torque in tapping on titanium alloys while performing axial and, axial and torsional vibration-assisted tapping (AVAT and ATVAT). The experimentation shows that both AVAT and ATVAT reduce the tapping torqueduring tapping as compared to that of in conventional tapping process. However, ATVAT process had exhibited a higher degree of reduction in torque when compared to AVAT process.

Abstract: The paper aims at issuing of a virtual simulation model that would be able to assess the actual working modes of a torque converter, both hydraulically and mechanically. To estimating the dynamic behavior we used the assessing equations of the converter’s performance coefficients. The rotational inertial phenomena due to the transient regimes during the getaway phase are also considered. The modeling process assumed the use of the pre-defined structures of the Simulink-Matlab and Simscape-Matlab modules. The virtual model of the torque converter was fed with the experimentally determined, performance parameters as input. The input also consisted of the inertia moments of the converter’s components. Eventually, by interrogating the simulation model, we’ve got and plotted the time histories of the converter’s impeller and turbine angular velocities during the vehicle’s getaway process.