Applied Engineering Letters

133-142

Authors: Tran Van Dua

For a machining processes, the material selection that is very important, greatly affect both on the economic and technical efficiency of these processes. The selection of each material often was considered many criteria, which have different values in different materials. Multi-criteria decision making that is a technique is used to slove with situations of this type. The collaborative unbiased rank list integration that is a recently proposed multi-criteria decision making method and has only used in a handful of published studies. In this study, this method was used to select the materials for the industrial fields. Material selection in three different areas was performed. In each case, the ranking results of the solutions by the collaborative unbiased rank list integration method were compared with those ones of other methods. The results showed that this method is completely reliable when using for material selection with the considering of multiple criteria. Moreover, the strength of this method is that it does not occur any ranking reversion phenomenon even when considered in different scenarios.

154-162

Authors: Ahmad K. Jassim, Raheem Al-Subar, Dhia Ch. Ali

Sustainable manufacturing technology is one of the requirements of the current industrial fields to reduce the weight and energy used. Friction stir welding (FSW) can be considered a quantum leap in the development of welding technology. A solid-state process utilizes a non-consumable tool and less electrical energy. Friction stir spot welding (FSSW) is a particular case of FSW that began to spread rapidly, especially for similar and dissimilar metals, which has extended to weld the polymers. The increase of FSSW use in different fields needs to simplify the equipment. This study used a portable drilling machine to construct an FSSW apparatus with a rotational speed between 1500 and 3000 rpm with a pin diameter of 2, 3 and 4 mm. The results indicated that the joints welded by the developed apparatus have good strength and hardness. Furthermore, many specimens succeeded in the bending test, especially when the rotational speed was set at 2250 rpm and the pin diameter was 3 mm. In addition, it was found that the mechanical properties increased with the rotational speed and pin diameter, then gradually decreased. Finally, the Response Surface Methodology (RSM), besides the analysis of variation (ANOVA), was utilized to maximize the lap-shear fracture load. The results indicated that the maximum lap-shear fracture load can be achieved at a tool speed N of {2300>N>1600} rpm with a pin diameter (d) of {2.75>N>3.75 mm}.

172-180

Authors: Kayode Saka, Bankole Adebanji , Paul Olulope, Taiwo Fasina, Adewale Abe, Wilfred Ajeba

In this work, a grid-connected small hydro-solar PV hybrid power system (HPS) was modeled to complement electricity supply in Ado-Ekiti metropolis in Nigeria, and hence, investigated the steady state stability of the distribution networks with and without HPS integration. Consumers’ load audit was carried out through measurement of apparent load at peak periods on each outgoing cable riser from the low voltage circuit of the distribution transformer using clamp-on ammeter which represents loads on respective 11 kV feeders. The solar PV system employed the use of JAP6- 72-30/4BB solar PV module and average solar radiation intensity of 4.95 w/m2 was considered when sizing the solar PV power system. The designed and modeled HPS was integrated into the grid through a hydro inverter and five numbers of parallel-connected 2000 kVA grid-tie solar PV inverters. Simulation analysis of the distribution networks with and without renewable energy integration was carried out using DigSILENT power factory. This work analyzed two scenarios for each of the distribution networks. Simulation results indicated that the networks were stable as evident in the analyses of the renewable grid integration and notable improvement on profile voltage (pu) of all the 11 kV distribution networks were observed.

89-99

Authors: Miloš Pešić, Nikola Jović, Vladimir Milovanović, Danilo Savić, Aleksa Aničić, Miroslav Živković, Slobodan Savić

The safety of the troop in an armored vehicle is paramount. The most serious threat to armored vehicles is a buried charge explosion or an improvised explosive device. The use of numerical approaches in the validation of armored vehicles minimizes the number of prototypes needed and speeds up the design process. This research focuses on blast simulation utilizing the ConWep (which stands for conventional weapon) method for STRENX armor steel used for blast protection in ALM (which stands for antilandmine) vehicles. The plate is modeled as a deformable solid with the Johnson-Cook plasticity model. In this paper protective plates were examined in order to determine which geometry gives the best protective conditions for the troop in an armored vehicle. Three different geometries were numerically tested, and two of them represent combined geometry. The maximal value of the plastic strain and maximal value of the vertical displacement of the central node on the protective plate was chosen as the parameters to represent the obtained results.

108-117

Authors: Yusra Jasim, Ghazwan Alwan, Tahseen Othman

Hydroforming has gained increasing attention in the manufacturing industry in recent years due to the demand for fast yet reliable production for parts, the applications of which accept a wide range of dimensional tolerances. In this study, tube hydroforming in conical dies has been analyzed. The study consists of two parts: computer simulations and experimental work. The simulation results were utilized to find the load paths which produce successful hydroforming for the selected tube specimens. Twelve load paths were identified and implemented with two friction coefficients and three pressure ranges. During the simulation process, the tubes were given an end movement that ranged from a sealing distance to twice that distance. The experimental work was implemented to verify some of the simulation results. The results showed that the best hydroforming limit was reached when the axial feeding was twice as much as the sealing distance. Also, the maximum amount of deformation rate happens shortly after the specimendie interface starts having relative motion, and it is at its slowest when the hydroforming reaches the fully-formed specimen’s shape.

125-131

Authors: Filip Klejch, Eva Schmidová, Tomáš Mejtský

Interstitial Free (IF) steels are nowadays commonly used for stamping complex parts of outer automotive bodies. Current requirements for fast production lead to the need of monitoring the real state of the material after stamping based on its real material conditions. It is desirable to describe and quantify the evolution of microstructure deformation and plastic conditions before and after the stamping process. This paper presents Electron Backscatter Diffraction analyses of deformed and non-deformed IF steel, including the quantitative measurement of the localized plastic response of the real stamped part, using an unconventional indentation method. The effect of strain rate was evaluated using the highspeed tensile tests. The increased ratio of the Low Angle Grain Boundaries was found as a good parameter to quantify the depletion of plasticity.

45-53

Authors: S. Grazion, V. Spiryagin, M. Erofeev, I. Kravchenko, Y. Kuznetsov, M. Mukomela, S. Velichko, A. Ašonja, L. Kalashnikova

The article presents the results of experimental estimation of the possibility of early registration of structural defects using the acoustic-emission method of control, based on the phenomenon of acoustic emission, which is the excitation of elastic vibrations of the material, caused by the formation and development of defects. To confirm the possibility of recording the processes of predestruction, such as the development of crack-like defects and plastic deformation using the acoustic-emission method of control, full-scale tests of the pressure vessel were carried out and the physical model of the shell-and-tube heat exchanger specially designed for this process was verified. It has been determined that the most informative frequency range for recording acoustic emission signals is the range of 100-200 kHz. The relationship of acoustic emission with the characteristics of defect development during plastic deformation has been studied. It was found that for reliable determination of the plastic deformation process, shared usage of amplitude and the count rate of acoustic emission is advisable.

67-73

Authors: M. Vite-Torres, M. Moreno-Ríos, A. Villanueva-Zavala, E. A. Gallardo-Hernández, L. Farfán-Cabrera, D. H. Mesa-Grajales

The phenomenon of cavitation erosion consists of the formation, growth, and collapse of bubbles in liquid media. The bubbles are responsible for the damage generated to metal and non-metal materials. Consequently, there is a pronounced degradation on the material surface, producing a scar in the impact area of the bubbles, and eventually the detachment of material. This experimental work aims to determine the performance of AISI 304 stainless steel base and coated with SiC. The SiC coating was obtained by the Chemical Vapor Deposition technique assisted by plasma. The tests were done through an ultrasonic cavitometer with a frequency of 28 kHz in an aqueous medium using tap water. According to the evidence of mass loss, results indicate that the stainless steel coated with SiC have better wear resistance than stainless steel base. In addition, failure mechanisms as cracking, plastic deformation, pits and others, were identified.

81-88

Authors: A. A. Patil, S. S. Desai, L. N. Patil, S. A. Patil

In the industry, ball bearings are the most widely used machine element. The ball materials may differ in various bearing applications. Wear of the ball and recess after a period of use is the most common cause of ball bearing failure. The present study aims to develop the artificial neural network model for assessing the wear of different ball bearing materials. A wear test method has been followed as suggested by the ASTM-G99 standard. The pin on disc apparatus was selected to conduct numerous trials. L9 array was considered to design the experiments. The factors considered for this study were load, time, and sliding speed. Based on the results obtained, ANN code was proposed to evaluate wear using numerous test parameters. The results obtained from the proposed model are nearly similar to experimental results, which would be evidence for the correctness of the model. The proposed neural network model can be used in numerous applications with given parameters.

1-9

Authors: D. D. Trung

This paper presents a research on investigating the effect of cutting parameters on the surface roughness (Ra) and roundness error (RE) when turning the interrupted surface of 40X steel. The TiN coated high speed steel (HSS-TiN) inserts were used in this research. The cutting parameters include cutting velocity, feed rate, and depth of cut. The Box-Behnken method was applied to develop an experimental matrix with fifteen experiments. The influences of cutting parameters on Ra and RE were found using Pareto chart. Two equations that presented the relationship between Ra, RE and cutting parameters were established. These two equations were used to predict Ra and RE. Genetic algorithm (GA) was also used to determine the optimal values of cutting parameters to simultaneously ensure the minimum values of Ra and RE. The further works of this study was also mentioned in this paper.

17-24

Authors: M. A. Kuznetsov, D. P. Il’yashchenko, E. V. Lavrova, S. A. Solodsky, О. А. Podgornyh, E. V. Verkhoturova

This paper presents the results of working out the modes of obtaining micro range powders according to the developed method. It is based on the navigation on the material of the vortex plasma flows of heterogeneous plasma and synchronized high-frequency impact on the electrode. The formation of powders is derived from individual particles heated and accelerated using a high-temperature gas jet - plasma. It is obtained in a special original plasma generator by blowing the plasma-forming inert gas into an electric arc resulting between two electrodes. The possibility of obtaining powders of various sizes and chemical composition by this method on the developed technology has been established. The design of the executive equipment that implements the studied generation process of the micro-size range is best suited for steel wires. Experimental studies made it possible to determine the optimal modes for wires of various chemical composition (steel wire, with a diameter of 1.2 mm, OK Autrod 347Si with a diameter of 0.8 mm). Range of parameters and modes of actuating equipment: current of 70-80A; Plasma-forming gas pressure 0.7-0.8 atm., Wire feed rate 20-40 mm/s, the frequency of ultrasonic oscillations of 50 MHz and 100 MHz. In these conditions, powders are obtained with a dimension of 50-100 μm.

32-44

Authors: M. Stanojević, R. Tomović, L. Ivanović, B. Stojanović

Planetary gear trains have been applied for a long time in the automotive industry as an irreplaceable part of automatic gearboxes. This paper presents, based on existing research, the kinematic analysis and evaluation of Ravigneaux gear trains, effects of power flow analysis and power loss, evaluation of utility effects of energy utilization through analysis of efficiency. It also illustrates research topics that analyse technical challenges of understanding and predicting dynamics and vibrations of planetary gear trains in the process of design of their configuration, optimization of given gear trains in reference to set criteria and affirmation of validity of their constructions by prototyping and prototype testing on the test stand.