International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The idea of creating and using digital twins has been strongly influenced by the process of integrating artificial intelligence methods with big data analytics of data from Internet of Things (IoT) devices. The concept of “Digital Twin” has become increasingly influential and culminating in the field of CPS. The main objective of the study is to define the basic requirements to the digital twins for cyber-physical system and based on the different definitions and components of digital twins, to summarize and analyze approaches, methods and tools used for their development. This analysis should serve as a basis for the development of a methodology for creating digital twins for cyber-physical manufacturing systems in the process industry.

The article briefly presents the possibilities of the created and verified model of polymer plasticization during injection molding. Exemplary characteristics generated by the model are presented and examples of applications of the described model for supporting the design of plasticizing systems of injection molding machines are indicated.

In the paper are presented theoretical analysis of the methods for industrial processes modeling and a new approach to modeling and simulation of industrial processes in cases of lack of information on the mechanism of the process.

The paper presents dynamic analysis of the Semi-Portal Cranes for the case of Trolley motion travelling on Crane’s Girders. Semi-portal cranes are mainly mounted in the industrial facilities, and they consist of metallic structures with big dimensions and many mechanisms that carry heavy loads. We will analyze the influence of the Trolley motion in the dynamic behavior of Semi-Portal Crane while carrying maximum Load, in particular the influence of Load swinging and oscillations. The method of analysis is acquiring experimental measurements and comparing those results with the results gained through modeling of crane, and carrying simulations. Designing the Crane’s 3D model with software and motion simulations is the method applied in the paper to analyze dynamics and is important to explain the form and intensity of oscillations that can cause accidents, failures of parts, and other concerns about the safety. Analysis will be done for maximal and minimal speed of the Trolley. Conclusions from this paper will be useful about the design, dynamic response and safety of Semi-Portal Cranes. The analysis will be focused to find main kinematic and dynamic parameters influencing the crane dynamics, like forces, moments, speed (velocity), and Load swinging magnitude. The Crane is modeled based on the Data from standard manufacturer of Semi-Portal Cranes.

This paper deals with Dynamic analysis of Scissor Lifts during the Load Lifting to determine their dynamic behavior, find the nature of oscillations, and the regulation of lifting to minimize these oscillations and optimize the work process. During the motion processes, the lift and its main parts undergo heavy forces, moments, and oscillations. The method of research is acquiring results through design, modeling, and simulations, comparing them with analytic calculations, and looking for the optimal motion regulation of the Load Lifting. The analysis will be acquired when the Scissor lift is carrying maximum Load. The study will be concentrated in the finding the nature of dynamic forces and stresses that acts on the main parts of the lift and the extent and the form of oscillations. Results will be shown in the form of diagrams and contour views as the solution results of the tested system. Modeling and simulations will be carried using software SimWise 4D, based on the type of the Scissor Lift taken from Standard Manufacturer. Conclusions of these analyses are useful for design considerations, dynamic behavior, and safety of these types of lifts.

Cyber-physical systems (CPS) integrate computing, networking and physical dynamics and are characterized by a high degree of heterogeneity and parallelism, with high dimensionality and complexity, including a variety of decision-making capabilities and control logic. Modeling and simulation of cyber-physical systems are considered important stages in the design, development and operation of CPS and their components. The main aim of the paper is to describe and analyze the evolution of agent based approach in the field of CPS and to define the basic requirements to the agent based systems regarding CPS. Based on O-MaSE methodology a software process model for agent based development of CPS is proposed. The approach includes the creation of 10 models reflecting various aspects and functionality of the CPS. The suggested approach is analyzed in terms of meeting the basic requirements for agent-based systems, imposed by the peculiarities of cyber-physical systems and fundamental requirements for their introducing, such as flexibility/changeability, reliability, reconfigurability, adaptability/agility and dependability.

This paper presents investigations of vibrations of cantilever beams with piezoelectric layers. The paper discusses the contemporary engineering and scientific software systems in order to select the appropriate for the study of mechanical and electrical dynamic behavior of piezoelectric beams.The system COMSOL has been chosen and a study with it has been stated with a static analysis and an eigenvalue analysis. Conclusions are made and a frequency response and time dependent investigations are planned to be done.

Low operating temperature, compactness, high efficiency as well as low to zero emissions are features that cause large interest in Proton Exchange Membrane (PEM) fuel cells and are reasons that application of this technology is considered in many areas. However, for a massive deployment of the PEM fuel cell technology to the market, good control and monitoring are mandatory to increase efficiency and durability. For the control and monitoring of PEM fuel cell systems, appropriate system models are required. In this study, a review of modeling approaches to the PEM fuel cell systems is considered

The microscopic and macroscopic views of copper electrodeposits obtained on plastically deformed copper substrates of different deformation degrees have been investigated. Experiments have been performed under galvanostatic conditions. There appear, depending upon the degree of reduction realized during substrate rolling, three types of deposit: epitaxial, homogenous and texture. Epitaxial growth is observed on unreformed substrate and on the substrates with lesser deformation degree (up to 60 %). With the increase of the substrate reduction degree, heterogeneous type of the deposit appeared and the phenomenon of twinning was stated. On very much deformed substrates, as well as in presence of organic additives, field oriented texture type of the deposit is obtained. On very deformed substrates macroscopic uneven deposits appeared, with the linear structure which follows the direction of substrate rolling. Possible explanations of this phenomenon are given.

Study the refusal of requests received in a specialized automotive service workshop in the city of Rousse was investigated. The present work analyses the average monthly requests from customers of the workshop and the number of the actual repairs is determined. The work in the service have been seen as a mass service system with a non-stationary mid-month incoming stream with queries. Under nonstationary conditions, the basic values of the system parameters were calculated and Mat Lab application was created. The proposed approach can serve as a methodology for analysing and optimizing the activity of other universal automotive service

An important requirement of digital electronic devices is the comprehensive provision of electromagnetic compatibility. In particular, it is necessary for electrical, electronic and radio equipment to ensure a sufficient level of noise immunity when exposed to microsecond pulse interference. The international standard IEC 61000-4-5 regulates the testing of equipment for microsecond impulse noise. Carrying out such physical tests is quite complicated and requires expensive equipment. The article proposes computer simulation of testing electronic devices in accordance with the requirements of IEC 61000-4-5.

In the last few years there has outlined a well-defined tendency to consider aviation security with regard to the optimal management of its level with the consistent solution of the identification, measurement, evaluation and decision-making problems. For this purpose aviation security is shown as a state related to the object’s under study defined parameters, the quantitative display of which in the dynamics of their changes under the influence of external and internal factors remains in acceptable limits in terms of the object’s operation. However, the environment is formed by the object’s safety equipment, which represent a definite list of technical and other functional elements, solving the problem of the internal and external factors countermeasure. If we consider the situation of counter-strategy as a pseudo field, the proposed model belongs to the class of boundary value problems described by partial differential equations. The problem has no analytical solution, and computational modeling is very limited by mathematical formalization’s issues. It is offered to use hybrid computer tools, which have undoubted advantages in this case.