Abstract: In order to obtain good quality of the machining surfaces, it is necessary for the cutting tools to be correctly positioned in relation to the workpiece. In the case of turning on CNC machines, the tip of the cutting insert must be placed in the axis of the semi-finished product without additional adjustments on this axis. The paper analyzes the precision of a turning tool because the problem (studied for an insert) can be used for a larger number of inserts placed on more complex tools. The key point that allows the correct design of the insert pocket on the tool body is specified. Also, the dimensional chain on the Y direction of the turning tool and the non-linear tolerance specifications of the cutting tool body have been established. PubDate: Sat, 07 Jan 2023 00:00:00 GMT
Abstract: Nowadays, there is a high demand for rapid prototyping parts and for products manufactured through plastic cold deformation. Incremental forming process is one of many which presents numerous advantages for fast production of complex shape parts. The purpose of this study is to develop a numerical model through finite element analysis to simulate the incremental forming process. For this analysis a variable wall angle part (VWA) which ranges from a 45° wall angle at the higher base of frustrum cone to a 70° wall angle at the base of the shape was proposed. The numerical model showed where the maximum strains are localized, how big the forces are during the process and how much the material thinned. Although the model does not indicate a possible failure of the material, the integrity of the structural stiffness was altered due to a minimum thickness reached of just 0.26mm. PubDate: Sat, 07 Jan 2023 00:00:00 GMT
Abstract: In this paper, the operation of a two-phase induction motor (TPIM) with non-orthogonal stator windings is studied, in a stationary reference frame. Through modeling and simulation on the Matlab/Simulink environment, the influence of the electrical shift angle stator windings on the magnetic and electromechanical quantities of the machine, in transient mode, will be highlighted. Also, another problem studied refers to the determination of the rotor flux of the TPIM by the estimation method, thus avoiding the use of the flux sensor. It was decided to use estimators derived directly from the machine equations written in motor mode, estimators used in electrical drives with analog control. And in this case, simulation was used to highlight, in a transient regime, the performance of using these flux estimators. PubDate: Sat, 07 Jan 2023 00:00:00 GMT
Abstract: In general, a large part of the time is devoted to the design and production of reliable parts where extensive knowledge is required for the design engineers to come up with an optimal solution for the tooling and sheet metal forming processes. Most of the time, the principle of trial and error is used to get the desired shapes for the products. This is because the prediction of deformations occurring in sheet metal elements is not available and is highly dependent on the geometry of the part, the tools and the deformation process. Prediction is limited by the proper location of necking, shear breakage, and puckering of the material. Searching for a robust deformation process by trial and error is expensive and inefficient. The use of numerical simulations provides engineers with an alternative efficiency for developing a tool and process to produce quality parts in a more efficient and lower cost. Computer simulation is an extension of theoretical science that is based on mathematical models. Such models attempt to characterize the physical prediction or consequences of scientific theories. The purpose of this work is to present the way of determining the forming limit diagram by various experimental methods. PubDate: Sat, 07 Jan 2023 00:00:00 GMT
Abstract: The paper presents the particularities of wire electric discharge machining (WEDM) regarding electrode tool vibration (wire tool vibration). It shows how the electrode tool vibrates and the vibration shape. The presented mathematical model can be successfully used in practice to improve the accuracy of processing through the wire electric discharge machining. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: The SPIF is a promising procedure in achieving unique and small series production. The paper’s aim is to present a succinct review of the latest research of the SPIF of polymers regarding process parameters and failure mechanisms. There are also presented some considerations regarding costs and energy consumption and the differences between SPIF of polymers and metallic materials. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: The aim of this paper is to present a system capable of modifying the human voice: volume by direct amplification/attenuation, duration of the voice signal and pitch using the Phase Vocoder, and timbre with the help of cepstral analysis. The system is also able to dynamically modify the aforementioned parameters in real-time. The proposed system was evaluated using a set of “clean” speech samples from the LibriSpeech ASR corpus of English speech with the Perceptual Evaluation of Speech Quality (PESQ) standard. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: Under discussion is the matter of processing hyperboloid surfaces using wire electrode discharge machining (WEDM). Let us consider a random hyperboloid surface which will help define the kinetics engaged in generating it. There will be illustrated the mathematical relations that make possible the engendering of hyperboloid surfaces, ensued by an exemplification of the way the processing works, highlighting its industrial role. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: In this paper, an open-loop speed estimation algorithm is proposed for an induction machine. The model used is based on the monitoring of stator voltages and currents, specific to a three-phase induction machine (TPIM) with known parameters. The performances of the proposed model will be tested on the MATLAB / Simulink simulation environment,[11] where it is observed that the open-loop speed estimator depends on the variation of the induction machine parameters. In order to improve the operating performance of the induction machine, this paper also uses a rotor flux estimator. Thus, the results obtained in this case will be verified on the used simulation environment. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: Since the beginning of the Covid-19 pandemic, carrying out of practical applications, it has been a challenge for technical higher education. Several technical disciplines, such as the strength of materials, requires students to access the laboratories and perform specific tests. Among these, the photoelasticity method is established for determination of the isocline and isochromatic families of curves. The method involves the analyze of an optically transparent, homogeneous and isotropic material, in an unsolicited state, through polarized light. This requires that the test specimen to be fixed into the polariscope, which implies the physical access of the students into the laboratory. The result obtained, as an image, is often blurred or hard to interpret. On the other hand, the determination of the above-mentioned families of curve by the finite element method (FEM) may be carried out remotely on any PC on which a specific finite element analysis program is installed, if the result of a tensile test on an identical specimen in shape and dimensions, as that one used for photoelasticity is transmitted to the users. In addition to the advantage of remote work, which can be overseen on a platform such as Microsoft Teams or Google Meat, once the analysis with the finite elements is completed, several additional results are available. In this paper, the authors aim to present the usefulness of using the finite elements method (FEM) as opposed to the photoelasticity method, especially under the circumstances of the Covid-19 pandemic. Also, at the end of the paper, a comparative table is presented containing the results that can be obtained by the two methods. PubDate: Thu, 30 Dec 2021 00:00:00 GMT
Abstract: This paper presents a technological breakthrough in the manufacturing of miniature revolving surfaces using wire electrical discharge machining (WEDM). The principle of manufacturing highlights specific aspects of the technology concerning the necessary equipment and the steps taken during production. The process of manufacturing is presented mathematically, concerning the surplus of material that is to be removed. The technological solution proposed was validated in practice and it features some experimental results that were obtained. This solution puts forward a new alternative to the manufacturing of small-sized revolving surfaces for hard and extra-hard material parts. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: Identifying birds in audio signals has been a challenge because the marking of certain species influences their classification. The proposed method consists of a mixture of sound processing for extracting useful signals from longer recordings with dynamic energy thresholds, image processing such as filtering and compression through image resizing for the treatment of the spectrogram and multilayer perceptron networks for the classification. The method shows encouraging results and flexibility, allowing the extension to a larger number of species, as well as applications to other fields involving sound or sound-like signals. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: Structural Health Monitoring (SHM) represents a method of monitoring and assessment of the structural state of a certain component, in terms of damage identification, damage classification and monitoring of deformations and loads. The structure and purpose of different SHM methods are presented, with a review of the main types of sensors and monitoring methods available. Recent trends in implementing SHM methods in composite applications are presented, especially in aerospace structures. Also, the main advantages and disadvantages of SHM methods are being highlighted and the potential that these systems have in the technological future. The main purpose of the presented survey is to assess the best method to realize a future model of a new composite blade, equipped with sensors, that will replace the current metal tail rotor blade which equips the IAR330 military transport helicopter used by the Romanian Air Force. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: The paper introduces some considerations on theoretical aspects focusing on increasing the degree of customer satisfaction in the field of public transportation, aiming to improve public relation by augmenting satisfaction. Ensuing the introduction of certain general aspects of the issue, opportunities offered by the EN 13816 European norm are presented, the latter providing useful instruments for improving the quality of public transportation services (the quality loop and the ways of evaluation of internal and external quality of transportation services). Throughout the paper, there have been briefly introduced characteristic elements of the European norm, its objectives, the preconditions for the application of the norm mentioned and the benefits of its implementation. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: This paper presents a brief description of the main systems found in a platform or in an autonomous omnidirectional mobile robot. Each system is described and presents its important role for the functionality of the robot and what are the advantages and disadvantages of using these systems. Concrete examples are presented for the omnidirectional locomotion system, the kinematics of the omnidirectional locomotion, the sensory system of the robot and the navigation systems that can be implemented. The paper wants to highlight the main systems that we must take into account in creating an autonomous mobile robot with omnidirectional wheels. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: The paper presents some generalities regarding business communication followed by a brief outline of the latter subject taught at the Faculty of Engineering Faculty, Sibiu, inflicting on its role upon the education of the future engineers. It also evaluates the effect of the skills acquired by students in the field of business communication regarding the valorization of specific professional competences. Based on several tests and surveys, this work presents aspects regarding the improvement of certain special skills such as: group communication, meetings, interpersonal, public and written communication. It seeks to evince communication-related issues which the students find most helpful in finding a job and also in their day-to-day business activity. To sum up, it is obvious that a continuous improvement of students’ knowledge and abilities in this field is imperative, so that the future specialists make the most of their technical knowledge. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: Single point incremental forming (SPIF) is a cold metal forming process, which is well known among researchers in the last years. This process differentiates itself from other classic cold forming processes due to the relatively low number of elements involved in the process, being suitable for small batches and prototypes parts. Taking advantage of their high flexibility, but at the same time losing the rigidity of CNC machines, industrial robots can be used in the incremental forming process, a process known as “roboforming”. One area of interest among researchers is represented by the forces which take place during the process, because they dictate whether an equipment is suitable or not in regards with material strenght. The aim of this paper is to investigate the influence of different toolpaths over the forces measured in SPIF which took place when DC04 sheet metal blanks were deformed with the help of KUKA KR210 robot. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: In this paper is presented a model of locomotion system with omnidirectional wheels for mobile platforms for the industrial environment. In the first part of the paper is made a brief description of the type of wheels used, what are their advantages and disadvantages. In the paper the emphasis is placed on omnidirectional wheels of Mecanum type and all their possibilities of movement are presented. Also presented is the design and sizing of a complete locomotion system for an omnidirectional mobile platform that serves the industrial environment. The chosen kinematic scheme and the calculation of the dimensioning of the necessary motors, the determination of the forces acting on the platform when moving in horizontal plane and the determination of the forces acting on the platform when moving on the ramp are presented. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
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