| Product Design and Development According to the Project of Equipping the Summer Kitchen and Bar using Sheet metal Bending Tools |
| Sandra Bedžeti, Graciela Šterpin Valić, Goran Cukor |
Abstract: The use of CAD/CAM programs has significantly reduced the time required for designing products, creating the necessary documentation, optimizing machines and creating CNC programs. The paper briefly describes the physical bases of sheet metal forming, then is stated the division of sheet metal forming processes into deep drawing, cutting (shearing, blanking and punching) and bending. In the following is started with modeling of the parts according to the project of equipping the summer kitchen and bar, and description of two modeling principles - bottom-up and top-down. Material chosen for production of the parts is austenitic stainless steel X5CrNi18-10. This is followed by a description of the procedures for 3D modeling of the parts and creating assembly in Autodesk Inventor program, the procedures for creating modeled positions, i.e. nesting, laser cutting and creating a CNC program for bending, and finally assembling and welding with the TIG process. Keywords: 3D modeling, assembly, bending, nesting, sheet metal forming |
| DOI: 10.47978/TUS.2023.73.04.001 |
| The Corrosion Behavior of Low-Alloy Steel 51CrV4 |
| Sunčana Smokvina Hanza, Mirta Uljar, Dario Kvrgić |
Abstract: The aim of this research was to analyze the corrosion behavior of low-alloy steel 51CrV4. To accomplish this, a series of electrochemical tests were conducted to estimate the corrosion rate of the steel samples. These tests were carried out in a 3.5% NaCl solution both before and after subjecting the steel to specific heat treatments, which included quenching, as well as quenching and tempering. Furthermore, an additional set of electrochemical tests was performed on 51CrV4 low-alloy steel samples that had previously undergone quenching and tempering process. These tests were designed to evaluate the corrosion rate under various environmental conditions, encompassing tap water, a 1% NaCl solution, a 3.5% NaCl solution, and a 5% NaCl solution. Additionally, a separate electrochemical test was conducted in a 3.5% NaCl solution, introducing two distinct inhibitors: glycerol and sodium thiosulfate pentahydrate. From the experimental results, it can be concluded that samples immersed in solutions with a higher NaCl concentration exhibited a higher corrosion rate than those in solutions with a lower concentration. It can also be concluded that sodium thiosulfate pentahydrate served as an effective corrosion inhibitor. In contrast, glycerol proved to be an ineffective inhibitor and actually increased the corrosion rate. Keywords: Corrosion, Corrosion rate, Electrochemical testing, Heat treatment, Inhibitors |
| DOI: 10.47978/TUS.2023.73.04.002 |
| Planetary Gear Trains Design Parameters Selection |
| Jelena Stefanović-Marinović |
Abstract: There are many benefits that are inherent to planetary gear trains (PGTs) which make them more suitable than classical gear trains. The most important of these advantages is a considerable reduction of mass and dimensions for the same torque rating. Because of that, the application of PGTs has been significantly expanded in various engineering applications. PGTs as a totality, and particularly complex multi-carrier PGTs cover a vast area of technical knowledge. Planetary gear trains the basic parameter is number of teeth of all gears, because the same or close transmission ratio can be achieved by different number of gear teeth. The uniqueness of the planetary gear trains puts on the need to also include the number of satellites. Thus, the number of satellites is also an important design parameter. All dimensions of gears are determined through gear module. It is the reason for selection gear module for significative design parameter. Face width is responsible for uniform distribution of load along the contact line. Center distance and addendum modification coefficients represent the measure of the train size. This paper gives the procedure for planetary gear transmissions design parameters selection which are predicted for using as variables in multicriteria optimization adjusted for basic type of planetary gear train. Keywords: the numbers of teeth of gears, number of satellites, module, center distance, face width |
| DOI: 10.47978/TUS.2023.73.04.003 |
| Application of the VIBROT Software for the Diagnosis of Rolling Bearing Failures |
| R. Tomović, D. Bratić, A. Tomović |
Abstract: The aim of this paper is to present the possibilities of using the VIBROT software for diagnosing failures that may occur in rolling bearings. The VIBROT is complex software for the diagnostics of rotary machines that was developed in the Laboratory for Mechanical Design at the Faculty of Mechanical Engineering in Podgorica. The software was developed inside the LabVIEW™ development environment, with the support of MATLAB®, which are the two most significant tools for signal acquisition and processing. The developed software was tested using an experiment. Real vibrations, that originate from faulty rolling element bearings, have been used in order to test the efficiency of the developed software. The obtained results suggest that vibration diagnostics of rolling element bearings could be performed efficiently with the use of signal processing techniques of VIBROT software. Keywords: VIBROT, software for vibro diagnostics, rotation machine, rolling bearing, Fourier transform, Envelope analysis, Cepstrum analysis, Spectral Kurtosis |
| DOI: 10.47978/TUS.2023.73.04.004 |
| Application of Two-Carrier Planetary Gear Trains to Shifting Gearboxes |
| Sanjin Troha, Željko Vrcan, Kristina Marković, Milan Tica, Miroslav Milutinović |
Abstract: This article deals with two-carrier planetary gearsets having two connecting and two external shafts, which may operate as two-speed gearboxes when brakes are placed on two external shafts. Analysis of the S16WN(S/E) gearbox is performed using the torque method, the specific torques are determined on all shafts, and then used to calculate both transmission ratios. The kinematic scheme of the gearbox has been synthesized, and the relative power flows have been identified. Efficiency functions are calculated for both gear ratios. The graphical representation of the transmission ratio functions for both gear ratios was used to obtain the diagram of the shifting capabilities of the S16WN(S/E) gearbox. The importance and utility of such diagrams and the relevant equations for the determination of ideal torque ratios of the component gear trains is explained. The size of the transmission ratio domain suggests that the S16WN(S/E) gearbox has a wide area of possible applications. Keywords: planetary gear train, gearbox, two-carrier, two-speed, ideal torque ratio, transmission ratio, efficiency |
| DOI: 10.47978/TUS.2023.73.04.005 |
| Željko Vrcan, Sanjin Troha, Kristina Marković, Milan Tica, Miroslav Milutinović |
Abstract: This paper deals with the comparison of two different simple planetary gearsets. The first type is a 2k-h, variant A geartrain, while the other is a simple planetary gearset with coplanar paired planets. Methods for the kinematic synthesis of both gear trains are explored, together with the analysis of the transmission ratios that can be achieved by the gearsets. Both gear trains are analysed for the possibility of operating as a reversing gear train within their design limitations. The type with paired planets is of particular interest, as it can be built in a configuration that will have a transmission ratio of -1. This also enables compound gear trains having equal transmission ratios in both directions of rotation of the output shaft to be built. Keywords: planetary gear train, simple gear train, coplanar paired planet gears, reversing gear train, compound planetary gear train |
| DOI: 10.47978/TUS.2023.73.04.006 |