Showing papers in "International Journal of Automotive and Mechanical Engineering in 2017"

Dynamics Properties of a Go-Kart Chassis Structure and Its Prediction Improvement Using Model Updating Approach

Abstract: Model updating is concerned about the correction of finite element models by processing the record of dynamic response from test structures in order to have an accurate model for any simulated analysis. Finite element model updating had emerged years ago as an important subject in structural dynamics. It has been used frequently and has been successfully applied to many fields especially in detecting the dynamic stiffness of a structure. The purpose of this study is to perform model updating of a go-kart chassis structure in order to reduce the percentage of error between the experimental modal analysis (EMA) and finite element analysis (FEA). Modal properties (natural frequency, mode shapes, and damping ratio) of the go-kart chassis structure were determined using both EMA and FEA. Correlation of the modal parameters gathered in FEA and EMA was carried out before optimizing the data from finite element. By adjusting the selective parameters, incongruities between those two analyses are generally reduced. The sensitivity of selected parameters is also obtained. The significant reduction in percentageof error before and after model updating procedure was carried out in this study clearly shows that model updating technique is a reliable method in reducing the discrepancies between EMA and FEA. Therefore, in cases of high discrepancies between analytical and actual test data, model updating can be considered as an option in order to obtain better correlation between those two sets of data.

Emission from a dual fuel operated diesel engine fuelled with Calophyllum Inophyllum biodiesel and producer gas

Abstract: In recent times, the rapid depletion of diesel fuel has resulted in its rising price and hazardous emission from the vehicles. Hence, an alternative fuel is immediately required for substituting diesel in order to improve the country's economic status and security. Therefore, this paper investigates the performance and emission characteristics of a diesel engine operated in dual fuel mode fuelled with calophyllum inophyllum oil methyl ester blends and rice husk generated producer gas. The engine test analysis was carried out at varying load conditions (0, 2, 4, 6, 8, 10 kW) keeping the producer gas flow rate constant i.e. at 21.69 kg/h. The experimental results depict that maximum diesel savings occurred for diesel with producer gas up to 82%, when correlated with the B20 biodiesel blend showing diesel savings of up to 80.6% at 8 kW of the optimum loading condition. Now, taking into account the emission parameter i.e. CO, CO2 and HC showed an increasing trend while, NOx and the smoke opacity reduced drastically for the dual operated mode. Hence, it might be concluded that the calophyllum inophyllum oil methyl ester with producer gas at a constant gas flow rate up to a 20% blend i.e. B20 can be utilised as potential fuel for current diesel engines without many engine modifications and problems.

A Performance Investigation on IoT Enabled Intra-Vehicular Wireless Sensor Networks

Abstract: The concept of Internet of Things (IoT) can be utilised in vehicles, since the number of sensor nodes in vehicles is rising tremendously because of the uplifting demand of applications for security, safety and convenience. In order to establish the communication among these nodes inside a vehicle, a controller area network with wired architecture provides a prominent solution. However, this solution is not flexible because of the architectural complexity and the demand for a large number of sensors inside the vehicle; hence wired architectures are replaced by wireless ones. Moreover, scalability will be an important issue while introducing the IoT concept in Intra-Vehicular Wireless Sensor Networks (IVWSNs). In this paper, a comprehensive performance investigation on the IoT enabled IVWSNs (IoT-IVWSNs) to be carried out in order to address this issue. The overview of the IoT-IVWSNs with a comparative study of the existing technologies and the design challenges for such network are provided. The link design between an end-device and the control unit is analysed, and the performance of the network has been investigated and some open research issues are addressed. It reveals that the delay in packet transmission increases due to higher traffic loads and the number of end-devices. This result demonstrates that the existing MAC protocol works well for a small network (i.e., a network with a maximum number of 50 nodes) but is not suitable for a large network (i.e., a network with more than 50 nodes). The outcome of this research helps to design a smart car system.

Analysis of a diesel engine fuelled with jojoba blend and coir pith producer gas

Abstract: The emission characteristics of Jojoba biodiesel and preheated Jojoba oil blends along with producer gas from coir pith, in a dual fuel diesel engine under two different experimental conditions, were measured. The present experiment the emission characteristics of a diesel engine that was operated in dual fuel mode. The producer gas is the main fuel and jojoba biodiesel blends and jojoba preheated oil are the injected fuel. Firstly, diesel, biodiesel blends, and preheated oils with coir pith generated producer gas were examined in both individual and dual fuel mode at a constant gas flow rate of 21.69 kg/hour at various loading conditions. Secondly, the same test fuels were taken at constant load and different gas flow rates at 10 KW in dual mode. An engine test analysis was carried out at varying load conditions (0 kW, 2 kW, 4 kW, 6 kW, 8 kW, and 10 kW) by keeping the producer gas flow rate constant i.e. at 21.69 kg/h. All emissions were seen to be on the higher side for preheated oil as compared to biodiesel producer gas dual fuel mode at all load conditions. The nitrogen oxides and smoke opacity were reduced, whereas carbon dioxide, carbon monoxide and hydrocarbon were increased for all test fuels in dual fuel operation as compared to a single style at different loading conditions. All fuel blends showed better emissions than that of diesel in both ways. Utilising jojoba biodiesel producer gas dual fuel mode, emission parameters like CO2, smoke and NOx are higher as compared to diesel producer gas operation. At optimal load condition, smoke emission for preheated oil producer gas dual fuel operation is 62% higher than the diesel producer gas mode. Diesel savings for diesel producer gas operation fetch up to 83% when correlated with B20 biodiesel producer gas blend up to 81.6%, at optimal load condition. Hence, it might be concluded that jojoba biodiesel producer gas up to 20% blend, i.e. B20, can be utilised as potential fuel for presenting diesel engine without much engine modification. Nevertheless, in the second case, with an increase in gas flow rate, all blended fuels showed better emissions with respect to diesel. The current paper also recommends further investigation to improve fuel properties and in-cylinder combustion phenomena of jojoba biodiesel before its usage in a dual fuel operated diesel engine.

A review on the purification and use of biogas in compression ignition engines

Abstract: Biogas is commonly produced during the decay of organic matter. It is a mixture of methane and some non-combustible gases such as CO2 and H2S. Its viability as a renewable alternative fuel for internal combustion engines can be enhanced by methane enrichment, i.e. removal of the non-combustible constituents. One of the common techniques for using biogas in a compression ignition (CI) engine is to mix it with air in the intake manifold, induct, and compress this mixture and ignite it by injecting a small quantity of diesel or bio-diesel, which is termed as the pilot fuel. This is known as the dual fuel mode. The pilot fuel is injected close to the end of the compression stroke as in a conventional CI engine and the injected fuel quantity depends on the operating condition. An alternative approach is the Homogeneous Charged Compression Ignition (HCCI) mode. Here, a homogeneous mixture of biogas and air is inducted and compressed by the piston until it auto-ignites. While this concept combines the benefits of spark ignition (SI) and CI engines, the onset of combustion cannot be controlled directly. A detailed review of recent research pertaining to biogas purification techniques and operation of CI engines with biogas in dual fuel and HCCI modes is presented in this paper. The effects of various operating parameters on engine performance and emissions, and comparison with conventional diesel fuelled CI engines are discussed. Biogas improves combustion efficiency, NOx, and smoke emissions. However, it reduces brake thermal efficiency, volumetric efficiency, and increases HC and CO emissions. Biogas fuelling of CI engines is recommended for achieving high diesel substitution, especially under high torque operation.

Energy saving technologies for urban bus transport

Abstract: Reduction of non-renewable sources of energy and the ecological state of metropolises have become the cause of the search for optimal solutions for introduction of energyefficient and environmentally friendly technologies for urban bus transport, which is the purpose of this work. A review of environmentally friendly buses has shown that electric buses (electrobuses) are the most perspective. However, rapid replacement of all the buses with electrobuses is impossible because of their high cost. A comparative analysis of the operating costs of different types of buses of the same destination and class has been carried out in order to choose the optimal variant. Thus, one route of 4.23 km in length was chosen in Kharkiv (Ukraine). Experimental and calculated data showed that a minibus converted into an electrobus is the most acceptable means for urban passenger transportation. Ultra-capacitors are suggested as an energy source. The conceptual diagram of the model of such a bus is presented and the technical requirements for its components are determined. The data and proposals are useful for Ukraine and for countries with low economic development that cannot quickly replace old diesel buses with new, environmentally friendly, electrobuses. The results of this work are the basis for further research and development.

Experimental Investigation on the Performance of the TiO2 and ZnO Hybrid Nanocoolant in Ethylene Glycol Mixture towards AA6061-T6 Machining

Abstract: This paper presents an experimental investigation on the coated carbide cutting tool performance of aluminium alloy AA6061-T6 machining through end mill processes using the minimum quantity lubrication (MQL) technique. The process parameters including the cutting speed, depth of cut and feed rate are selected. The effect of the base fluid ratio (water: EG) to the hybrid nanocoolant was investigated in this experiment. The hybrid nanocoolant with 80:20 of volume concentration up to 0.1% was prepaid with a 21 nm particle size of TiO2 and 10-30 nm ZnO nanoparticle for measurement purposes and tested at cnc end milling machines. The analysis of the variance method is utilised to validate the experimental data and to check for adequacy. The response surface method was used to develop the mathematical models and to optimise the machining parameters. It is observed that the material removal rate depends significantly on the depth of cut and feed rate, followed by the spindle speed. The results can be used as an example of the minimum quantity lubricants (MQL) technique applied to the machining of aluminium alloys, providing economic advantages in terms of reduced the machining costs and better machinability.

New design concept of a tank made of plastic material for firefighting vehicle

Abstract: Optimisation work has been increasingly directed at commercial vehicles to reduce their weight and thus enhance their performance. This optimisation, which responds to the requirements of various European standards with regard to the reduction of fuel consumption, also involves the elements mounted on these vehicles. This work discusses the development and design of a firefighting vehicle tank made from plastic material instead of the usual structure or stainless steel, essentially to reduce the weight of the structure. The design and construction feasibility of the components have been developed based on the specifications required. These specifications concern the tank capacity to resist at different load conditions and avoid any external vibrations. To ensure this, the tank consists of a number of internal welded plates in order to reduce the sloshing effect and secondly makes it modular and thus highly adaptable to the customer’s needs. Specific method on the production of the component is also provided. Therefore, numerical tests were conducted with linear elastic stress analysis with square brick elements. The boundary conditions applied to the numerical model provide a complete support to the panels and are determined by the load condition of fluid used. This preliminary analysis was conducted to define the thickness of the tank panels and revealed that the use of a plastic tank leads to a weight reduction of about 35% and generates cost savings of about 25-30% compared to the steel equivalent. Therefore, the use of plastic materials compared to the classic materials seems to be very positive and this is critical information to support the final decision in a regulated sector, where the firefighting vehicles are.

Heat Transfer Enhancement Using Hybrid Nanoparticles in Ethylene Glycol Through a Horizontal Heated Tube

Abstract: Heating hybrid nanofluids by the mixing of solid nanoparticles suspended in liquid represents a new class of heat transfer enhancement. To enhance heat transfer for many industrial applications, a computational fluid dynamics modelling simulation using the finite volume method and adopting the SIMPLE algorithm was performed. The mixture of aluminium nitride nanoparticles into ethylene glycol which acts as a base fluid is considered as a new concept of hybrid nanofluids that can increase heat transfer. The hybrid nanofluid was prepared experimentally with a volume fraction range of 1% to 4%. The size diameter of nanoparticles, heat flux around a horizontal straight tube, and Reynolds number is approximately 30 nm, 5000 w/m2 and 5,000 to 17,000, respectively. The computational method had been successfully validated using available experimental data reported in the literature. It was found that 1% to 3% Aluminum nitride hybrid nanofluids can significantly affect efficiency, while more than 3% volume fraction are insignificant as they obtain less than one efficiency. Results show that a combination of aluminium nitride nanoparticles with the EG base fluid tends to augment heat transfer performance significantly.

Analysis of a quarter car suspension system based on nonlinear shock absorber damping models

Abstract: Shock absorber is a critical element of vehicle suspension system with nonlinear characteristics. In the present work, performance of vehicle characteristics was analysed by quarter car model to study the effect of shock absorber, on the basis of linear and nonlinear damping characteristics. In addition to linear and piecewise linear, polynomial damping characteristics were considered to address the nonlinear aspect of damping characteristics. The linear and nonlinear properties of the shock absorber were incorporated in a two degree of freedom quarter car suspension system. The modelling and simulation is carried out in Adams view environment and Matlab/Simulink. A bump road profile was used to excite the quarter car suspension models. The polynomial shock absorber model was validated using experimental data taken from established literature. Simulation was undertaken to study the dynamic performance in terms of sprung mass acceleration, body displacement, suspension deflection and unsprung mass acceleration. Experimental hysteresis characteristics data, taken from established literature, were also modelled in Adams view environment and the simulated results were used for validation purpose. The suspension system response incorporating shock absorber represented by nonlinear model, hysteresis model and piece wise linear model were provided in the result section for comparison. It was observed from quantitative comparisons that the RMS values for body acceleration and body displacement of the polynomial model matched fairly well with the results of experimental hysteresis response. It was concluded that in order to study the dynamic characteristics of the vehicle accurately, nonlinear behaviour of the damper is required to be captured properly. Therefore, the proposed polynomial shock absorber model can be a better option for vehicle dynamic analysis as compared to the complex hysteresis model.

Performance and emission characteristics of micro gas turbine engine fuelled with bioethanol-diesel-biodiesel blends

Abstract: Biodiesel is receiving increasing attention as an alternative fuel due to the ever-growing demand for energy. However, the inferior physiochemical properties of biodiesel render it incompatible for gas turbine application, which needs to meet the standard requirement of gas turbine fuel accordance to ASTM D2880. In this quest, the biodiesel-diesel– bioethanol blends might be a good option. In this paper, the research work was carried out to study experimentally the performance and exhaust emission characteristics of a 25kW micro gas turbine engine (Capstone Model C30) fuelled with biodiesel-dieselbioethanol blends. The assessment on the improved fuel properties of biodiesel by blending with bio-ethanol had shown more superior atomisation characteristics performance compared to unmodified biodiesel. Moreover, the performance test in the micro gas turbine was limited up to 20% blend of biofuel, which showed improved thermal efficiency during the test. Subsequently, the emission test carried out in this work also showed significant enhancement in emissions, except nitrogen oxides (NOx) which contributed to the higher formation in comparison with the distillate diesel. Finally, B80E20 (80:20 of biodiesel-bioethanol) was proposed to be selected as an ideal blended fuel ratio to be applied in micro gas turbine engine due to its adaptability to replace diesel fuel, while showed better performance and emission properties as compared to the pure petroleum diesel.

Physico-mechanical properties of coir and jute fibre reinforced hybrid polyethylene composites

Abstract: Composite materials are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components. A hybrid composite refers to a special type of composite which contains more than one fibre material as reinforcing filler. Multiple fibre reinforced composites give a wide variety of mechanical properties with respect to a single fibre containing composite. The ecofriendly nature as well as the processing advantage, light weight and low cost have enhanced the attraction and interest of the natural fibre reinforced composite. The objective of the present research is to study the mechanical properties of the jute-coir fibre reinforced hybrid polyethylene composite. Composites were manufactured by using a hot press machine at three levels of fibre loading (5, 10 and 15 wt%). The tensile, flexural, impact and hardness tests were conducted for the purpose of mechanical characterisation. A water absorption and scanning electron microscopic analysis was carried out as part of the physical evaluation. The tensile test of the composite showed a decreasing trend of tensile strength and an increasing trend for Young’s modulus with an increasing fibre content. During the flexural, impact and hardness tests, the flexural strength, flexural modulus, impact strength and hardness were found to be increased with the increasing fibre loading. Water absorption increased with the increase in fibre loading. The scanning electron microscopic analysis showed the strongest adhesion between the fibre and the matrix in the 15% fibre reinforced composite. Based on the fibre loading used in this study, the 15% fibre reinforced composite exhibited the best set of mechanical properties.

Performance and emissions of diesel engine fuelled with preheated biodiesel fuel derived from crude palm, jatropha, and waste cooking oils

Abstract: Biodiesel is typically made by chemically reacting lipids of palm, vegetable, and waste cooking oils and animal fat with an alcohol producing fatty acid esters. Biodiesel is not efficient in cold weather and this is biodiesel’s major problem. Viscosity has influences on the fuel flow rate and leads to poor fuel atomisation during the combustion process. The aim of this study is to determine the effects of biodiesel temperature in the range fom 40 °C and 60 °C on engine performance such as torque, brake power, brake mean effective pressure, and fuel consumption. Three types of biodiesel oil were used (crude palm oil (CPO), waste cooking oil (WCO), and jatropha oil) under biodiesel blending ratio of 5vol%. A single cylinder four-stroke engine was used and operated under different load conditions of 0% and 50% and observed emission of CO, CO2, NOx, and HC. The engine operated at 0% and 50% dynamometer load conditions and running speeds of the engine of 800 rpm, 1200 rpm, 1600 rpm, and 2000 rpm. The results of this study showed that the heating temperatures in the range from 40 °C and 60 °C in CPO10 produced the highest brake power as well as torque and BMEP. For the experimental results of exhaust emission, the preheated temperature affected the degradation of the exhaust emission. In addition, preheated biodiesel increased the pressure on the cylinder combustion chamber. It can be concluded that the biodiesel preheated blend influences the performance and emission. For CPO biodiesel, the preheated biodiesel decreased CO and NOx while the standard diesel produced the lower emission of CO2 and HC. WCO biodiesel blend produced a lower emission with increasing fuel temperature.

Energy analysis of a stepped cascade solar still connected to photovoltaic thermal collector

Abstract: In this paper, the performance evaluation of a stepped cascade solar still connected to photovoltaic thermal (PV/T) collector was carried out. The governing equations of problem was a set of initial value ordinary differential equations which were obtained by writing energy balance for the various components of solar still system (i.e. glass cover, brackish water, absorber plate, and PV/T collector). The numerical model of problem was solved by the 4th-order Runge-Kutta method under real climatic conditions sample. The validation of numerical model was carried out by the experimental data of previous literature. Parametric studies showed that the energy efficiency of stepped cascade solar still maximised in the desired brackish water flow of 0.03 kg/min and the PV/T collector area of 1.3 m. The daily energy efficiency and accumulated freshwater were about 26% and 5.71 kg/(m.day), respectively. An increase of about 20% was obtained in freshwater productivity by the connection of PV/T collector to the stepped cascade solar still. Also, PV/T collector, in addition to providing pumping power, can supply electrical power of about 0.918 kW/day for other uses. In order to produce freshwater during the night time, the usage of the phase change materials below the absorber plate was suggested.

Multidisciplinary design optimisation methods for automotive structures

Abstract: Multidisciplinary design optimisation (MDO) can be used as an effective tool to improve the design of automotive structures. Large-scale MDO problems typically involve several groups who must work ...

Automobile spare-parts forecasting: A comparative study of time series methods

Abstract: In Mexico, the automotive industry is considered to be strategic in the industrial and economic development of the country because it generates production, employment and foreign exchange. Good demand forecasts are needed for better manufacturing management. The time series modelling tools applied to the monthly demand forecasting of automobile spare parts in Mexico are assessed, for the case of a transnational enterprise, considering affordability. The classic methods of moving averages, final value and exponential smoothing, the prestigious autoregressive integrated models of moving averages (ARIMA), the rarely implemented artificial neural networks (ANNs) and the very little explored ARIMA-ANNs hybrid models are compared. A good performance of the models involving ANNs is observed, but they were not as steady as the ARIMA models in the post-sample periods. The mean absolute percentage error (MAPE) was reduced from an original 57% to 32.65%. The obtained results could help demonstrate the importance of improving industrial forecasting methodologies for better planning.

Characterisation of Activity Based Costing on Remanufacturing Crankshaft

Abstract: Traditional cost accounting applied by most remanufacturing industries assumes that manufacturing overheads are driven by the volume of production. However, this would not give a good measure of the actual manufacturing cost per unit because the overheads should actually be apportioned over the number of activities that are required to perform. Eventually, the cost of remanufactured crankshaft becomes obviously incorrect while the profitability becomes vague. The aim of this work is to estimate the cost of remanufactured crankshaft using activity based costing. The overhead costs are apportioned to activity drivers in accordance with the way resources are consumed and then, the overhead costs are apportioned from each activity driver to each cost object in proportion to the amount of the cost driver consumed by the product. The proposed method is validated by an industrial practitioner and expected to be able to serve as a useful approach because it produces a cost with accurate allocation of overhead, provides cost information on the cost drivers and produces accurate manufacturing cost and profitability information. This work is also supported by the Ministry of International Trade and Industry of Malaysia by proposing accurate allocation of overhead to strengthen the national remanufacturing policies for the development of remanufacturing industries as these industries need to sustain their end of life products.

Investigation and optimization for the dynamical behaviour of the vehicle structure

Abstract: Conceptual modelling is known as a well suited alternative approach for Computer-Aided Engineering (CAE) analysis in automotive industry. In this paper, an improved conceptual modelling method in which beams and panels of the structure are modelled as simplified beam elements has been proposed. To explore the advantage of conceptual modeling in determining the resonant frequencies/mode-shapes, a case study for wheelhouse was performed. Firstly, an experimental test and advanced CAE analysis were carried out to measure the wheelhouse dynamic characteristics. The advanced CAE model was then validated by means of Modal Assurance Criterion and natural frequencies by associated experimental measurements. The results of wheelhouse concept model compared to the advanced CAE and experimental model in low frequency range, showed that the error percent of natural frequency is lower than 10% and the Modal Assurance Criterion is above 0.75 for the first four mode shapes of wheelhouse structure. Finally, the conceptual model is used as a baseline for optimization. The genetic algorithm was implemented to maximize the first natural frequency to 41.74 Hz. So The genetic algorithm successfully provided new possibility for optimization by attempting to influence the first mode shape by means of the cross section characteristics. Due to the accuracy and reliability of developed conceptual model, this modelling approach can be a crucial tool in CAE and vibration analysis of vehicle in the early design phase. The proposed method allows the designer to give the results of design changes very quickly by neglecting details. Therefore, for the analysis of the vehicle performance in NVH domain, the proposed method could be considered in the conceptual design phase.

Morphological analysis of injected sprays of different bio-diesel fuels by using a common rail setup controlled by a programmable electronic system

Abstract: Biodiesel fuels are increasingly attracting interest in the scientific community and in the world motor industry. The morphological analysis of injected sprays is a key factor to increase engine performances using new biodiesel fuels and to compare them with those related to the use of conventional fuels. In this paper, an experimental setup is realised to carry out test campaigns, in order to analyse and compare the spray injections of different fuel typologies. A PC-interfaced electronic system was realised for driving BOSCH injectors and for varying the injection pressure and opening time. Hence, the morphological analysis was performed for each tested fuel by characterising the shaperatio and penetration depth inside the velocimetric chamber. The results show higher penetration values for biodiesel fuels due to their viscosity and drops in superficial tension, which facilitate a deeper penetration compared to those obtained with conventional diesel fuels. Although used biodiesels contain only 20% of renewable vegetable-origin diesel fuels, the viscosity and superficial tension are slightly higher than those of petroleum diesel, thus determining a weak vaporisation and formation of larger drops. By knowing the morphological behaviour of sprays using biofuels and conventional fuel, it is possible, by using programmable electronic systems, to adjust and improve the spray parameters in order to obtain better engine performances. The results reported in this instance could be utilised by future research works for choosing the most suitable biofuel based on the desired morphological behaviour of the injected sprays.

Archachatina marginata bio-shells as reinforcement material in metal matrix composites

Abstract: Snail shells (SnS), which represent the discarded bio-shell waste of snails’ remnants from restaurants and eateries constitute a serious degree of environmental threat with little or economic value. The effective utilisation of this waste into a green metal matrix composite as a low cost reinforcement material applicable in the automotive industry in lieu of its present hazardous impact had stimulated the research interest. Hence, this paper studies the potential utilisation of SnS as a low cost reinforcement material in the metal matrix composites (MMCs) by means of a characterisation technique. The mineralogical composition and physical properties of the snail shell powder was carried out using the density determination, thermogravimetric analysis (TGA), refractoriness, energy dispersive X-ray (SEM/EDX), X-ray fluorescent (XRF) and the X-ray diffraction (XRD) analysis at 0, 800, 850 and 900 C calcined temperatures for 3hrs. The results obtained show that the snail shell powder possesses chemical hard phase oxides (CaO, Fe2O3, Al2O3, Cr2O3, SiO2, MnO and NiO) at all calcined temperature values. The maximum amount of these phases was formed at a 900 C calcined temperature. The XRD analysis also confirmed the presence of calcite (Ca6C6O8), lime (Ca4O4) and portlandite (CaO2H2) as the thermally stable major hard phases of the SnS calcined at 900 C. The density and refractoriness temperature of the snail shell powder as obtained in this study are 1.63 g/cm and 1400 C. The TGA result shows that the SnS attained its thermal stability at 840C. The above results imply that SnS with (9.4-25.9) % lesser density when compared with agro or industrial wastes reinforcement material (flyash, coconut shell ash, maize husk, bagasse) in the metal matrix composite looks promising as a reinforcing material in the production of light weight metal matrix composites at low costs. Also, the high refractoriness temperature of the snail shell particle suggested it as a suitable candidate reinforcement material in the production of thermal resistance MMCs applicable in automotive components such as pistons and connecting rods.

Safety assessment of corroded jacket platform considering decommissioning event

Abstract: Continuous assessment of aged offshore structures is becoming extremely important to avoid any hazardous consequences throughout their design life. In Malaysian waters where most of the offshore structures are jacket platforms, it was found that many of these structures are currently operating beyond their design life. With continuous corrosion taking place, structural reliability and operation will be affected. Therefore, for the safety evaluation, this study focuses on the reassessment of an existing aged jacket platform in Malaysian waters pertaining to corrosion effect. In this study, pushover analysis was carried out to determine the ultimate strength of the corroded jacket platform by quantifying the reserve strength ratio value. Two different time-dependent corrosion wastage models were used in the present study to simulate the corrosion behaviour at the splash zone of the jacket platform. It was observed that average corrosion condition relatively simulated the calm waters of Malaysia and by applying this corrosion, the jacket platform can withstand the environmental load acting on it. The results developed in the present study will be useful for future study in predicting and modelling corrosion tolerance of jacket platforms in Malaysian waters.

The effect of oxygen content in soapnut biodiesel-diesel blends on performance of a diesel engine

Abstract: In this study, 18 soapnut biodiesel-diesel blends along with soapnut oil as an additive in some blends were prepared and used in a diesel engine to investigate the effect of oxygen content in the fuel blends on engine performance and emission characteristics. Considering the large variations in the oxygen content of these fuel blends, the obtained results were demonstrated based on varying fuel oxygen content. Findings showed that the best engine performance was achieved with a fuel oxygen content in the range of 1.8%–3.0%, whereas the best engine emissions were obtained with a fuel oxygen content in the range of 0.71%–2.37%. Hence, considering both engine performance and emissions, the optimal zone of fuel oxygen content was found to be in the range of 1.80%– 2.37%. Thus, it can be concluded that biodiesel blended fuels having an oxygen content in the aforesaid range can be successfully used in diesel engines with comparable engine performance and emissions to those using diesel fuel. Nevertheless, further research is required to reduce the fuel oxygen content to this optimal range if the blends consist of higher biofuel components. Besides that, the use of suitable additives in the biodiesel blended fuels may be a viable option to achieve the said purpose, which needs further research.

Experiments on the wear characteristics of A356 MMNCs fabricated using ultrasonic cavitation

Abstract: The wear properties of nanocomposites are evaluated in the present work. Owing to its good castability, A356 has been chosen as matrix material. Since Nano silicon carbide (SiC) and A356 are close in terms of density, SiC has been selected as reinforcement material. The dispersion of nano sized reinforcements in the metal matrix composite is challenging due to their higher surface to volume ratio of particles which results in agglomeration and clustering. Hence, the author had proposed an ultrasonic probeassisted stir-casting method in this work for a uniform distribution of particles in the melt. Due to the nano sized reinforcements, interaction at the phase interface becomes enhanced due to the increased surface area which leads to improved material properties, even at a low weight fraction of the reinforcement. So, Nano SiC particles of size 50nm (from 0.1 to 0.5 by wt %) were added. Through SEM microstructures, it has been observed that reinforcements were well-dispersed in the aluminium matrix. Test specimens were prepared and tested as per ASTM standard. The experiments were conducted using a pin on the disc wear tester at different loads (30N & 40N) and at constant speed. With the addition of 0.5 wt % of nanoparticles, the wear resistance of the nanocomposites improved by 53.735% and 47.04% at 30N and 40N respectively compared to pure aluminium alloy.

Optimisation of gate location based on weld line in plastic injection moulding using computer-aided engineering, artificial neural network, and genetic algorithm

Abstract: Gate location is one of the most important design elements of an injection mould. Injection moulding is a very complex process with several parameters having interactive effects on each other; hence, computer-aided engineering and artificial intelligence were utilised to optimise mould design based on weld line. Therefore, the finite element analysis, artificial neural network and genetic algorithm were linked to find optimum gate location in a plastic product. A reliable numerical model was developed by Moldflow software based on a real product to simulate injection process. Moldflow was used to predict weld line length and position of the part. Weld lines are visually undesirable and a plastic part is structurally weak at weld line positions. This study describes how the weld line was formed on the part. Polyamide-6 (PA-66) was used as the plastic material. To find optimum gate location, the finite element predictions were implemented to train a neural network, which was used later in the genetic algorithm. The optimisation objective was to find gate location which led to minimum weld line length. This research concluded that the developed procedure can efficiently optimise complex manufacturing processes and prevent flaws in products and thus, can be applied practically in the injection moulding process.

MHD slip flow and heat transfer of Casson nanofluid over an exponentially stretching permeable sheet

Abstract: The aim of the present paper is to discuss the boundary layer flow induced in a nanofluid due to a stretching permeable sheet in the presence of a magnetic field. Instead of no-slip boundary conditions, slips at the boundary have been considered. Casson fluid model was used to characterise the non-Newtonian fluid behaviour. The effects of Brownian motion and thermophoresis on heat and mass transfer were considered. Using similarity transformations, the governing partial differential equations were transformed into ordinary ones. The self-similar equations were then solved numerically using shooting technique with fourth order Runge-Kutta method. The solutions for velocity, temperature and concentration fields depended on the pertinent parameters. It was observed that the velocity decreased but the temperature and nanoparticle volume fraction increased with the increase of Casson fluid parameter. With the increase in velocity slip parameter as well as magnetic parameter, fluid velocity decreased. Due to increase in thermal slip, temperature decreased and with the increase in mass slip parameter, concentration also decreased. Temperature was found to increase but the nanoparticle volume fraction decreased due to the Brownian motion. On the other hand, temperature and nanoparticle volume fraction were both found to increase with the increase of thermophorosis parameter as well as with the increasing strength of magnetic parameter. Thus, velocity slip at the boundary and magnetic parameter acted as flow controlling parameters. It is believed that this type of investigation is very much helpful for the manufacturing of complex fluids and also for cleaning oil from surfaces.

Comparison of properties of mwcnt/carbon fibre/ epoxy laminated composites prepared by solvent spraying method

Abstract: The incorporation of multi-walled carbon nanotubes (MWCNT) in laminated composites is believed to improve the mechanical and thermal properties of the composites. However, the nature of the MWCNT, which tend to agglomerate and form into ropes, restricts their dispersion in the composites. MWCNT-filled carbon fibre laminated composite was fabricated via hand lay-up followed by the vacuum bagging technique. MWCNT at different loadings of 0.5 to 1.0 vol% was dispersed by a solvent spraying method with two different dispersing agents, namely ethanol and Triton X100. The flexural and thermal properties of the hybrid laminated composites were investigated. The CF laminated composites filled with 1.0 vol% of MWCNT dispersed in ethanol possessed better mechanical properties than other hybrid CF composites. Keywords: Carbon fiber; multi-walled carbon nanotubes; flexural properties; thermogravimetry analysis

A progress review in wire electrical discharge machining process

Abstract: Wire Electrical Discharge Machining (WEDM) is an electrothermal non-traditional machining process used for machining electrically conductive materials that are difficult to machine. Material removal in WEDM is by means of spark erosion. WEDM is proven to be the alternative for producing complex parts with higher degree of dimensional accuracy and better surface finish. Over the years, a significant amount of research was globally carried out to explore the WEDM process capability. This paper aims to explore the research work carried on parametric influence of WEDM process variables on various output performance measures. The paper also highlights various modelling techniques to predict optimal machining conditions and explore the feasibility of applying WEDM process to machine advanced materials. Combined technology that benefits from the virtues of WEDM and conventional method is also highlighted in this paper. The final section discusses the development and possible research trend in WEDM process.

Analysis and study of the influence of the geometrical parameters of mini unmanned quad-rotor helicopters to optimise energy saving

Abstract: The article discusses lift force generated by mini UAVs (Unmanned Aerial Vehicles). CFD (Computational Fluid Dynamics) simulations were made on the base of a 3D scanned propeller model. Influence of some geometrical parameters of propeller (like velocity or pitch) and quadcopter (like gap) on lifting force was considered. Different propeller pitches were used and pitch influence on propeller lift force was analysed. Normally, lifting force will increase with the increasing of propeller pitch but for different rotation velocities, this increasing is different and in all cases, it can be approximated by a linear relationship. To obtain dependency functions, an equation for calculation of lift force given took into account the correction coefficients. This equation gave reliable results at pitch values equal to 0.3 – 0.7 of the propeller diameter and at rotation velocities of 2000 min – 8000 min. Lift force dependency from distance between rotors was also considered. Simulations and experiments showed that the lifting force of a quadcopter increased about 15% on gap distances from 5 mm to 35 mm. From a distance of 70 mm, the lifting force will decrease about 2% and then will stabilise. At increasing of distance between propellers from 5 mm until 25 mm, the power consumption decreased 8% 10% and after the gap distance equal to 40 mm, it will be stable and minimal. It can be asserted that quadcopters have different optimal distances between the propellers at different rotation speeds to generate the same force. Equations for calculation of optimal gap distances for different multicopters were derived and calculation results are presented in graphs and