Showing papers in "International Journal of Automotive and Mechanical Engineering in 2013"

Experimental Measurements of Nanofluids Thermal Properties

Abstract: Solid particles dispersed in a liquid with sizes no larger than 100nm, known as nanofluids, are used to enhance Thermophysical properties compared to the base fluid. Preparations of alumina (Al2O3), titania (TiO2) and silica (SiO2) in water have been experimentally conducted in volume concentrations ranging between 1 and 2.5%. Thermal conductivity is measured by the hot wire method and viscosity with viscometer equipment. The results of thermal conductivity and viscosity showed an enhancement (0.5–20% and 0.5–60% respectively) compared with the base fluid. The data measured agreed with experimental data of other researchers with deviation of less than 5%. The study showed that alumina has the highest thermal conductivity, followed silica and titania, on the other hand silica has the highest viscosity followed alumina and titania.

The effect of methanol-diesel blended ratio on CI engine performance

Abstract: In the current work, a comprehensive study on the possibility of using methanol as an alternative fuel for diesel engines was carried out. Methanol was mixed at different ratios with diesel fuel. The mixing ratios of methanol to diesel were 0:100, 10:90, 20:80 and 30:70. The effects of methanol fraction on engine power, torque, brake specific fuel consumption (BSFC), brake thermal efficiency and exhaust temperature were experimentally investigated at variant engine speeds. The engine used to carry out these experiments is a four-stroke four-cylinder diesel engine. The results showed that mixing methanol at different fractions with diesel fuel has a significant effect on the engine performance. The methanol to diesel ratio of 10:90 exhibited the lowest exhaust temperature and achieved an improvement in the output power of approximately 70% compared to the other ratios. Also, the brake thermal efficiency improved at all the mixing ratios used. Furthermore, the BSFC of pure diesel fuel registered a lower value than any other mixing ratio. It has been shown in this research that the addition of 10% methanol to the diesel fuel may have a great impact on the engine performance and the environment

Investigation of Aluminum-Stainless Steel Dissimilar Weld Quality using Different Filler Metals

Abstract: Aluminum-stainless steel dissimilar welding processes yield unwanted disadvantages in the weld joint due to the large difference between the aluminum-stainless steel sheets’ melting points and the nearly zero solid solubility between these two metals. Aluminum AA6061 and stainless steel SUS304 were lap-welded by using Metal Inert Gas (MIG) welding with aluminum filler ER5356 (Group 1) and stainless steel filler ER308LSi (Group 2). The effects of the welding voltage and type of filler metals used on the weld joints were studied. The welding voltage had a significant effect on the welding process, as higher voltage resulted in poorer appearance of the weld joint and led to defects for both groups, such as porosity and incomplete fusion. The microstructure for Group 1 joints shows enrichment of Si particles, which benefited the joint properties as it increased the strength of the metal. The stainless steel substrates that spread into the aluminum side are much greater in volume for Group 1 than for Group 2 joints. Meanwhile, the microstructure of Group 2 joints (using ER308LSi filler) consists of chromium carbide precipitation which yields a high hardness value, but a brittle structure. The hardness values of the welded seams in Group 1 and Group 2 range from 60 to 100 HV and 160 to 230 HV, respectively. The fracture in the tensile test yielded the highest tensile strength of 104.4 MPa with aluminum fillers. The tensile strength of Group 1 joints ranging from 47.8 to 104.4 MPa was collectively higher than Group 2 joints, between 20.24 to 61.76 MPa. Based on the investigation throughout this study, it can be concluded that the welding voltage of 18 V and aluminum filler ER5356 is the optimum filler in joining the dissimilar metals aluminum AA6061 and stainless steel SUS 304.

Influence of Nanoparticle Volume Fraction, Particle Size and Temperature on Thermal Conductivity and Viscosity of Nanofluids- A Review

Abstract: In the present paper a critical literature review of nanofluid thermal conductivity and viscosity is performed. Experimental studies are discussed in terms of the effects of some parameters such as particle volume fraction, particle size, and temperature on thermal conductivity and viscosity of nanofluids. Theoretical models are explained, model predictions are compared with experimental data and discrepancies are indicated.

Application of Multibody Simulation for Fatigue Life Estimation

Abstract: In automobile design, the safety of passengers is of prime concern to the manufacturers. Suspension is one of the safety-related automotive systems which is responsible for maintaining traction between the road and tires, and offers a comfortable ride experience to the passengers by absorbing disturbances. One of the critical components of the suspension system is the knuckle, which constantly faces cyclic loads subjecting it to fatigue failure. This paper presents an evaluation of the fatigue characteristics of a knuckle using a gravel road profile acquired using a data acquisition system and standard SAE profiles for the suspension (SAESUS), bracket (SAEBRAKT) and transmission (SAETRN). The gravel road profile was applied as the input to a multi body simulation (MBS), and the load history for various mounting points of the knuckle is extracted. Fatigue life is predicted using the strain-life method. The instantaneous stress distributions and maximum principal stress are used for fatigue life predictions. From the results, the strut connection is found to be the critical region for fatigue failure. The fatigue life from loading extracted from gravel road MBS agreed well with the life prediction when standard SAE profiles were used. This close agreement shows the effectiveness of the load extraction technique from MBS. This method can also be effectively used for more complex loading conditions that occur during real driving environments.

Experimental Investigation on Heat Transfer and Pressure Drop Characteristics of Air Flow over a Staggered Flat Tube Bank in Crossflow

Abstract: This paper presents an experimental investigation into the heat transfer and pressure drop characteristics of air flow in a staggered flat tube bank in crossflow with laminarforced convection. Measurements were conducted for sixteen tubes in the direction of flow and four tubes in rows. The air velocity varies between 0.6–1.0 m/s and the Reynolds number varied from 373 to 623. The total heat flux supplied in all tubes are changed from 967.92 to 3629.70 W/m2. The results indicate that the average Nusselt number for all the flat tubes increased by 11.46–46.42%, with the Reynolds numbers varying from 373 to 623 at the fixed heat flux. The average Nusselt number increased by 21.39–84%, and the total heat flux varyied between 967.92–3629.70 W/m2 with a constant Reynolds number Re = 498. In addition, the pressure drop decreased with an increase in the Reynolds number. A new mean Nusselt number-Reynolds number correlation was found, and the correlation yielded good predictions for the measured data with a confidence interval of 98.9%.

Effect of Compressed Natural Gas Mixing on the Engine Performance and Emissions

Abstract: Cleaner air quality is becoming a global concern, thus to improve the fuel and combustion process is vital. In this paper, computational fluid dynamics (CFD) analysis software CFD-ACE is used to investigate the flow behavior of methane and air in a compressed natural gas (CNG)–air mixer to be implemented in a CNG–diesel dual-fuel stationary engine. The effect of the number of mixer holes on the mixture quality was evaluated. The results of the 3D CFD simulation showed that the 8-hole Venturi mixer gave superior performance compared to the 4-hole mixer. Further analysis was carried out on the 8-hole Venturi mixer to investigate the effect of engine speed on the mass flow rate of CNG and the equivalence air to fuel ratio (1/). The second half of the paper presents comparative performance results between a single cylinder research compression ignition (CI) engine fueled with a CNG–diesel system and a conventional CI engine fueled by conventional diesel. The engine was equipped with the simulated 8-hole Venturi mixer. The result showed a significant reduction in exhaust gas emission components (NOx, CO and CO2) from the CNG–diesel engine compared to the conventional diesel engine, i.e. the reduction rates were on average of 54%, 59% and 31% respectively. The average power output developed by the dual-fuel engine was 10% higher than the diesel over the power curve.

Stability and Thermal Conductivity Characteristic of Carbon Nanotube Based Nanofluids

Abstract: Heat transfer fluids such as water, ethylene glycol and engine oil are commonly used in heat exchanger applications. However these fluids posses low thermal conductivity. The technology advancement in nanotechnology has enabled the nano size particles to be included in a base fluid. This new generation of fluid is known as nanofluids. Producing a stable nanofluid with improved thermal conductivity is a challenging process. The suspended nanoparticles tend to sediment with respect to time. In the present study, multiwall carbon nanotubes (MWCNT) based nanofluids with or without surfactant were investigated in the aspect of stability and thermal conductivity. Study implies that nanofluids added with polyvinylpyrrolidone (PVP) surfactant exhibit better stability compared to nanofluids without surfactant. About 22.2% thermal conductivity improvement was observed for water containing 0.5wt% of MWCNT and 0.1wt% of PVP surfactant. The thermal conductivity also increases with the increasing of MWCNT’s weight fraction.

The analysis of recirculation zone and ignition position of non-premixed bluff-body for biogas mild combustion

Abstract: Combustion ignition study is important due to the combustion process becoming more lean and efficient. This paper studied the recirculation zone and ignition location for the bluff-body non-premixed MILD burner with biogas used as fuel. The location of the ignition was critical to ensure the spark energy supply during the ignition process is successful ignite the mixture of air and fuel. The numerical calculations were done using the commercial code ANSYS-Fluent to simulate the furnace with bluff-body burner to determine the recirculation zone. The turbulence model used was the realizable k-e model. The inner recirculation zone between the air and fuel nozzle is the best location for the ignition point since low velocity of air and fuel mixing will assist the ignition process. This is because the ignition energy will have time to ignite the mixture in the low speed of turbulent swirl flow. The most suitable location with the highest possibility of ignition is the centre of the recirculation zone.

Modeling and Torque Tracking Control of Permanent Magnet Synchronous Motor (PMSM) for Hybrid Electric Vehicle

Abstract: This paper presents a detailed derivation of a permanent magnet synchronous motor, which may be used as the electric power train for the simulation of a hybrid electric vehicle. A torque tracking control of the permanent magnet synchronous motor is developed by using an adaptive proportional-integral-derivative controller. Several tests such as step function, saw tooth function, sine wave function and square wave function were used in order to examine the performance of the proposed control structure. The effectiveness of the proposed controller was verified and compared with the same system under a PID controller and the desired control. The result of the observations shows that the proposed control structure proves to be effective in tracking the desired torque with a good response. The findings of this study will be considered in the design, optimisation and experimentation of series hybrid electric vehicle.

Estimation of the Dynamic Properties of Epoxy Glass Fabric Composites with Natural Rubber Particle Inclusions

Abstract: Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm) when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%.

A Study on Lean Manufacturing Implementation in Malaysian Automotive Component Industry

Abstract: Lean manufacturing is an extended version of the Toyota Production System (TPS). It was highlighted as the best practice in the 21st century. Therefore, top and senior management in manufacturing firms are encouraged to adopt and adapt lean principles and practices in running their respective firms. The main objective of this paper is to investigate the extent of lean manufacturing perception and implementation in the Malaysian automotive component industry. A survey questionnaire was developed to collect top and senior management views with respect to their perception, judgement and opinion on twenty four lean manufacturing (LM) practices. This preliminary survey was conducted at 30 Malaysian automotive component manufacturing firms. The survey results show that a large majority of respondents have a high perception of the importance of lean manufacturing practices. However, it was found that their actual LM implementation is still on the low side. In this study, the non-parametric test was used to analyze the level of perception and implementation of the twenty four LM practices. The analysis of the survey results revealed that there are significant differences between the level of perception of the importance of LM practices and their actual implementation.

Effect of different heat transfer models on a diesel homogeneous charge compression ignition engine

Abstract: Homogeneous charge compression ignition (HCCI) engine technology is relatively new and has not matured sufficiently to be commercialized compared with conventional engines. It can use spark ignition (SI) or compression ignition (CI) engine configurations, capitalizing on the advantages of both: high engine efficiency with low emissions levels. However, the combustion behavior in an HCCI engine is difficult to predict because it has no spark plug or injector. The chemical kinetics mechanism influences the combustion with some heat losses to the cylinder wall. The effect of different heat loss models in a diesel HCCI engine has to be investigated further. A single-zone thermodynamics model was used in this study along with three different heat loss models: Woshcni, modified Woschni, and Hohenberg correlations. The results will be validated against experiments, and a good heat loss model will be used for further investigation of combustion behavior.

Continuous biodiesel production using ultrasound clamp on tubular reactor

Abstract: Biodiesel is an alternative fuel to be substituted with diesel fuel for diesel engines. It consists of alkyl monoesters of fatty acid from vegetable oil or animal fats and it is an alternative feedstock that can be converted into biodiesel at lower cost. A fast and low cost method to convert vegetable oil into biodiesel through the use of ultrasound clamp assistance has been investigated. The approach of this production is by using the ultrasound clamp to enhance the immiscible liquids between the vegetable oil and alcohol to emulsify together in a short period of time comparing to conventional stirring method which takes longer time for esters to form. The ultrasound causes the rapid movement of fluid hence creating cavitation where the liquids breaks down and cavitation bubbles created. The optimum results for biodiesel production using ultrasound clamp assisted on the tubular reactor is 3 minutes with the conversion of esters 90 % compared to the previous pilot plant unit which achieve 98 % of esters conversion within 5 minutes. The newly fabricated small pilot plant has indeed able to achieve the esters conversion with the presence of methanol to oil molar ratio of 12:1, catalyst concentration of 1,25 %wt and reaction temperature of 64°C. The newly fabricated small pilot plant has been developed in this research to facilitate the transesterification process in producing biodiesel from vegetable oil.

Integrated Simulation Model for Composition and Properties of Gases in Hydrogen Fueled Engine

Abstract: The composition and thermodynamic properties of combustion products are essential for evaluating the performance of internal combustion engines. This paper presents a simulation model named „HydEnPro‟, to predict the composition and thermodynamic properties of the multi-component gases in hydrogen fueled engine. HydEnPro was developed a set of codes for predicting the chemical equilibrium composition with two databases (NASA and Chemkin) that contain the thermodynamic information about the molecules. The developed codes accessed the thermodynamic databases and equilibrium codes predicted the properties of the multi-component gases. The predictions of HydEnPro were validated against the well-recognized Chemkin Tables, the standard literature and other general simulation models. It shown HydEnPro translation for the databases and its interfaces are correctly implemented. In addition, the accuracy of HydEnPro was emphasized. Hence,HydEnPro can be used in a predictive manner.

CFD investigation of in-cylinder air flow to optimize number of guide vanes to improve CI engine performance using higher viscous fuel

Abstract: This paper investigates the in-cylinder air flow of a compression ignition (CI) engine modified by a guide vane swirl and tumble device (GVSTD) where the number of GVSTD vanes was varied to optimize its dimension to improve the CI engine performance using higher viscous fuel (HVF). Hence, eleven 3D CI engine models were developed; a base model and 10 GVSTD models, via SolidWorks. Computational fluid dynamics (CFD) were performed by utilizing ANSYS-CFX and simulated under motored conditions for two continuous complete cycles. The results are presented of the simulation of in-cylinder pressure, turbulence kinetic energy (TKE) and velocity during the fuel injection period until expansion. The recorded increments from six vanes of GVSTD were about 1.3%, 0.2% and 22% of the above results. Hence, this paper concludes that GVSTD has the potential to improve CI engine performance using HVF.

Microstructure and fatigue properties of dissimilar spot welded joints of aisi 304 and aisi 1008

Abstract: Carbon steel and stainless steel composites are being more frequently used for applications requiring a corrosion resistant and attractive exterior surface and a high strength structural substrate. Spot welding is a potentially useful and efficient jointing process for the production of components consisting of these two materials. The spot welding characteristics of weld joints between these two materials are discussed in this paper. The experiment was conducted on dissimilar weld joints using carbon steel and 304L (2B) austenitic stainless steel by varying the welding currents and electrode pressing forces. Throughout the welding process; the electrical signals from the strain sensor, current transducer and terminal voltage clippers are measured in order to understand each and every millisecond of the welding process. In doing so, the dynamic resistances, heat distributions and forging forces are computed for various currents and force levels within the good welds’ regions. The other process controlling parameters, particularly the electrode tip and weld time, remained constant throughout the experiment. The weld growth was noted for the welding current increment, but in the electrode force increment it causes an adverse reaction to weld growth. Moreover, the effect of heat imbalance was clearly noted during the welding process due to the different electrical and chemical properties. The welded specimens finally underwent tensile, hardness and metallurgical testing to characterise the weld growth.

Atmospheric corrosion of structural steels exposed in the 2004 tsunami-affected areas of aceh

Abstract: Aceh province located at the northwestern tip of Sumatra Island in Indonesia has a coastal environment and a coastline of around 1660 km. Banda Aceh, Aceh Besar, and Aceh Barat are among the districts of Aceh Province located on those coastlines. The earthquake and tsunami that struck Aceh in December 2004 caused much of these districts to be submerged by seawater. Thus, the environment of these areas might become more corrosive. This study investigates atmospheric corrosion of structural steels exposed to the environment by the 2004 tsunami. Some typical structural steels, which have five different shapes, were selected for the test. Atmospheric corrosion tests were employed by referring to ASTM G50 standards. Eight locations were selected as the test sites: Peukan Bada, Ulee Lheu, Lingke, Lampulo, Suak Ribee, Suak Pandan, Suak Seuke, and Suak Geudebang. Following a six-month exposure, experimental results show that the atmospheric corrosion rate for Peukan Bada, Ulee Lheu, Lingke, Lampulo, Suak Ribee, Suak Pandan, Suak Seuke, and Suak Geudebang was 0.043– 5.451 mpy, 0.035–3.804 mpy, 0.058–5.332 mpy, 0.045–9.727 mpy, 0.265–3.957 mpy, 0.073–2.970 mpy, 0.090–4.101 mpy, and 0.380–6.379 mpy, respectively. The results show that the relative corrosion resistances for all structural steels exposed in these areas can be categorized as good to outstanding. Hence, it is safe to utilize the selected structural steels regarding their atmospheric corrosion resistance.

Finite Element Modeling of Delamination Process on Composite Laminate using Cohesive Elements

Abstract: The implementation of cohesive elements for studying the delamination process in composite laminates is presented in this paper. The commercially available finite element software ABAQUS provides the cohesive element model used in this study. Cohesive elements with traction-separation laws consist of an initial linear elastic phase, followed by a linear softening that simulates the debonding of the interface after damage initiation is inserted at the interfaces between the laminas. Simulation results from two types of composite laminate specimen, i.e., a double cantilever beam and an L-shape, show that the delamination process on laminated composites begin with debonding phenomena. These results indicate that the implementation of cohesive elements in modeling the process of delamination in laminated composite materials, using the finite element method, has been successful. Cohesive elements are able to model the phenomenon of delamination in the specimens used in this study.

Optimal automobile muffler vibration and noise analysis

Abstract: The muffler is the main part of the Automobile Exhaust System, consisting of fibrous and porous materials to absorb noise and vibrations. The exhaust gas mass coming from the engine can produce resonance, which may be the source of fatigue failure in the exhaust pipe due to the presence of continuous resonance. The modes on the muffler should be located away from the engine’s operating frequencies in order to minimise the resonance. The objective of this paper is to determine the frequencies that appear at the modes, which have the more adverse effect during the operation of the automobile. An impact test has been conducted by applying the force using a hard head hammer, and data generated have been used for plotting a graph of the transfer functions using MATLAB. Six points have been selected, namely 1, 2, 3, 4, 7, and 11 on the muffler for the impact test. The collected data from theses six points have been analysed for the addition of damping. Results suggests that increasing the mass increases the damping and lowers the modes of the transfer function. Further research will identify higher strength materials that can withstand the higher gas temperatures as well as the corrosion and erosion by the gas emitted from the engine.

Improved Vibration Characteristics of Flexible Polyurethane Foam via Composite Formation

Abstract: Flexible polyurethane (PU) foam is used as cushioning material in automotive seating for load bearing. Owing to the demand for more comfortable compartments, seat cushions are now designed for better ride comfort, which is linked to the damping of seating foam. In this paper, PU polymer was mixed with short treated coir fibers (F) and recycled tires (P) to enhance damping and improve the vibrational characteristics of seating foam. Five samples with 2.5wt% filler loading were developed. The vibration characteristics of foam composites were examined by transmissibility tests generated at 1 and 1.5 mm peak amplitude in the frequency range of 2–20 Hz, using a shaker, shaking table, and a foam-block system. The foam-block system was fabricated by simulating the seat/occupant system in an automobile. The damping properties of foam composites were calculated from the transmissibility data obtained. The results showed that more vibration was dissipated by the developed foam composites after the fillers were added. System inserts with PU+2.5wt%P gave the lowest resonance peak: 2.460 and 2.695 at 1 and 1.5 mm base excitation, respectively, compared with 2.788 and 2.878 obtained from system inserts of pure PU foam. This is because a higher damping ratio (ξ foam) was found in PU+2.5wt%P, which is 36.47% and 19.23% higher than pure PU foam. In addition, other composites, such as PU+2.5wt%F, PU+2.5wt% (50F50P), PU+2.5wt% (80P20F), and 2.5wt% (80F20P) also showed favorable vibration and damping characteristics in the experiments. When compared with the conventional seat cushions used in the Proton car, foam composites could offer better vibration dampening at resonance.

Validation of crack interaction limit model for parallel edge cracks using two-dimensional finite element analysis

Abstract: Shielding interaction effects of two parallel edge cracks in finite thickness plates subjected to remote tension load is analyzed using a developed finite element analysis program. In the present study, the crack interaction limit is evaluated based on the fitness of service (FFS) code, and focus is given to the weak crack interaction region as the crack interval exceeds the length of cracks (b > a). Crack interaction factors are evaluated based on stress intensity factors (SIFs) for Mode I SIFs using a displacement extrapolation technique. Parametric studies involved a wide range of crack-to-width (0.05 ≤ a/W ≤ 0.5) and crack interval ratios (b/a > 1). For validation, crack interaction factors are compared with single edge crack SIFs as a state of zero interaction. Within the considered range of parameters, the proposed numerical evaluation used to predict the crack interaction factor reduces the error of existing analytical solution from 1.92% to 0.97% at higher a/W. In reference to FFS codes, the small discrepancy in the prediction of the crack interaction factor validates the reliability of the numerical model to predict crack interaction limits under shielding interaction effects. In conclusion, the numerical model gave a successful prediction in estimating the crack interaction limit, which can be used as a reference for the shielding orientation of other cracks.

Analysis of woven natural fiber fabrics prepared using self-designed handloom

Abstract: Woven fabric as composite reinforcement structure has been profoundly investigated to be utilized in automotive, aircraft, agriculture, furniture and defense industry application. Woven fabrics are formed in particular by interlacing of yarns to form a fabric layer. This interlacing of fiber bundle offered advantages in terms of good dimensional stability and high packing density. Due to environmental issues, woven fabric sourced from natural fiber (NF) had gained greater attention. However the methods of woven preparation by means of NF yarns were found to be very limited. Most of the study is focusing on woven structure from fiber strand and it was prepared without specific device. Hence, the challenge addressed in the previous works had triggered research in designing and developing a weaving device suitable for yarns of thick and coarse natural fibers. In this research, a tabletop natural fiber weaving device was designed and fabricated which capable to weave NF yarns with different fabric degree of tightness. Fabrics characterization was analyzed and the static penetration test was conducted. Results demonstrated that fabrics with lower porosity value had greater puncture resistance and higher deflection rate at failure.

Evaluation of Annoyance and Suitability of a Back-Up Warning Sound for Electric Vehicles

Abstract: This paper describes the evaluation of the annoyance and suitability of a back-up warning sound for electric vehicles (EV). Three back-up signals used for the evaluation were categorized into three types: broadband, tonal and multi-tone. The reversing sound for a Nissan Leaf (EV-first mass production) will also be included as a benchmark for the other three sound signals. The sample sound was generated based on the human hearing threshold in several individual related areas; age-related, normal and working noise exposure frequency range. Each sound was evaluated in turn by the respondents in a nearby neighborhood, college, town area and rural area in terms of level of annoyance and its suitability as an EV back-up sound to alert pedestrians as they run quietly on the road, which can cause a hazard. Every tested sound perception result is based on the place where the respondents live. An appropriate sound for a quiet vehicle can help pedestrians to detect it and at the same time maintain acceptable environmental sound levels.

Modeling of the end milling process for aluminum alloy AA6061T6 using hss tool

Abstract: This study is focused to determine the optimum operating parameters for end milling process of AA6061T6 with wet cooling conditions. Central composite design of response surface methodology is used to develop an effective analytical model for surface roughness. The primary cutting parameters namely; speed, feed rate and depth of cut are considered in this study. Surface roughness is measured using a perthometer. The adequacy of the model is tested using ANOVA at 95 % confidence level. Significant parameters are identified in terms of the cutting parameters. The obtained results show that the most significant parameters for the machining of the mentioned alloy are feed rate and depth of cut. The resultant model is then tested for optimization using genetic algorithm.

Fatigue life prediction of commercially pure titanium after nitrogen ion implantation

Abstract: Prediction of fatigue life has become an interesting issue in biomaterial engineering and design for reliability and quality purposes, particularly for biometallic material with modified surfaces. Commercially pure titanium (Cp-Ti) implanted with nitrogen ions is a potential metallic biomaterial of the future. The effect of nitrogen ion implantation on fatigue behavior of Cp-Ti was investigated by means of axial loading conditions. The as-received and nitrogen-ion implanted specimens with the energy of 100 keV and dose of 2 × 1017 ions cm-2, were used to determine the fatigue properties and to predict the life cycle of the specimens. The effect of nitrogen ion implantation indicated revealed improved the tensile strength due to the formation of nitride phases, TiN and Ti2N. The fatigue strength of Cp-Ti and Nii-Ti was 250 and 260 MPa, respectively. The analytical results show good agreement with experimental results.

Pattern Development for Manufacturing Applications with Fused Deposition Modelling – A Case Study

Abstract: The purpose of this paper is to examine the suitability of fused deposition modelling (FDM), for the production of a pattern that can be used in direct manufacturing applications. In this work, the benchmark was identified and its best part orientation in a FDM machine was located through experimentation. Control charts and process capability histogram were drawn to assess the process capability of the FDM process. The micro hardness of the prepared sample was measured to check the suitability of the process for investment casting applications. Further dimensional accuracy of patterns was established by IT grades as per the ISO standard UNI EN 20286-I (1995). It was observed that the performance indices for all the dimensions in the present study are greater than 1. The study of photo micrographs using SEM gave an insight into the properties of the component (produced by FDM). This study highlights that the tolerance grades for ABS plastics are consistent with the permissible range of tolerance grades as per the ISO standard UNI EN 20286-I (1995) and DIN16901 standard.

Lean Manufacturing Perceptions and Actual Practice Among Malaysian SME’s in Automotive Industry

Abstract: Stiff business challenges and product competition faced by automotive component manufacturers has forced them to look into lean manufacturing (LM). Presently there are more than 100 LM practices. However, small and medium enterprises (SMEs) are not able to implement all LM practices due to financial, expertise and skill constraints. Therefore, in this study the authors investigated the level of perception and actual practice within 24 LM practices, regarding actions believed feasible to be implemented in SMEs. In addition, the authors gathered LM information sources, reasons for implementing LM and its benefits to SMEs. A questionnaire survey was conducted in 35 SMEs involves in manufacturing automotive components. The majority of SMEs have a high perception of the importance of LM practices but in reality are not undertaking them. The SMEs mainly received their LM information from their customers, and they strongly believe that LM practices could improve their long-term business sustainability and competitiveness in the market place.

Vortex Tube Air Cooling: The Effect on Surface Roughness and Power Consumption in Dry Turning

Abstract: There has been an increase awareness to reduce environmental impact in the last 10 years. The manufacturing industry is striving to reduce environmental impact by introducing new materials with better characteristics, consume less processing power and use less amount of processing coolant. The main objective of this paper is to study the effect of Ranque-Hilsch vortex cooling tube on power consumption and surface roughness quality in turning process when machining mild steel material with coated carbide cutting tool. The machining parameters involved in the experiment are cutting speed, feed rate and depth of cut. The cutting speed is fixed at 160 m/min while the feed rate and the depth of cut are varied. The feed rates used are 0.10, 0.18 and 0.28 mm/rev, while the depth of cut is varied from 1.0 to 4.0 mm. During the machining process, the cutting temperatures are measured using an infrared thermometer and the power consumption measured using a Prova 6830 power and harmonics analyzer. The machined parts surface roughnesses are measured using a surface roughness tester. The results show that cooling using Ranque-Hilsch vortex tube air cooling reduces the cutting temperature, but the power consumption and surface roughness is better under ambient condition except at higher feed rate.

Gasification of Coal-Petcoke Blends in a Pilot Scale Gasification Plant

Abstract: This paper investigates the synergistic interaction in a gasification of coal and petcoke blends in a 150 kWth pilot scale gasification plant. Petcoke was used either in combination with coal or separately to produce syngas in an atmospheric fluidized bed gasifier using air as gasifying agent. Syngas composition and carbon conversion efficiency were recorded and calculated. The results show that the increase in petcoke content in the fuel blend tends to lower the syngas composition. In addition, the carbon conversion efficiency also decreased with the increase in petcoke percentage in the blend. However, the conversion efficiency and syngas composition started to increase again when the petcoke percentage in the blend was more than 50%. As far as the mixture of coal and petcoke is concerned, optimum gasification efficiency was obtained at a 90:10 coal:petcoke blend. The lowest heating value was observed when the mixture was at 50:50. Therefore this mixture needs to be avoided when gasifying the coal: petcoke blend because it has the minimum gasification efficiency.