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

This work reports preliminary outlined relations between geometrical parameters and material parameters of smoothbore barrel and projectile during the internal stage of shot depending on the time variation of barrel pressure. Mechanical behaviors of barrel possessing diameter 18.2mm with length 760mm and projectile having cylindrical form with half-spherical form in the nose are 3-D modeled by help of the commercial Finite Element Method program product Ansys LS-DYNA. A barrel and three projectiles with different densities under five different friction conditions are numerically modeled with aims to establish both the projectile displacements and velocities, and related kinetic energy. Four stages in the projectile diagrams “Displacement-Time” and “Velocity–Time” are established correspondingly to the “Barrel Pressure –Time” diagram. Stress and strain states of barrel and projectile are reported.

Development of artificial intelligence in recent years has opened new possibilities in numerical analysis and engineering design. This paper systemizes the main area of applications of artificial intelligence in engineering with emphasis on computational mechanics. Fundamental approaches of machine learning are described including artificial neural networks, convolutional neural networks (CNN) and physics-informed neural networks and their integration with the finite element method. Additionally, a review is given on the platform ANSYS SimAI platform which combines predictive accuracy of numerical simulations with the speed of generative artificial intelligence in a cloud or local computer environment reducing computational time by one or two orders of magnitude. It is worth noting that artificial intelligence is not a replacement for classical analysis, but a powerful tool which speeds up the innovation process and can expand boundaries of numerical modeling in engineering

The present study concerns the simulation, in two dimensions, by the finite element method, of the behaviour of the magnetic field created by sources of equivalent neuronal currents by considering a simplified model of a diagnostic device used in MEG (Magnetoencephalography). The simplified geometric model is composed of the head, the magnetic field sensors and the sources of equivalent currents representing the neurons. The geometric model of the head is represented by 3 layers which are brain, bone and skin. The sensors placed above the part of the skin make it possible to calculate the electric voltage induced by the magnetic field resulting from the sources of equivalent currents produced by the neurons. Neurons are represented by equidistant point current sourcesThe Maxwell-multi physics software has been used.

A group of numerical methods suitable for describing the propagation of light in a Photonic Crystal Fiber (PCF) are discussed. PCFs can be classified according to the mechanism of light propagation. The methodology of the analysis is briefly reviewed to understand how changing the different physical parameters of the fiber and the design affects its optical properties. By analyzing the systematic studies presented, a design with the desired optical fiber properties can be realized.
PCFs can be made from just one material with two-dimensional photonic crystals or periodic arrays of air holes parallel to the fiber axis to form a shell and core shape. Several types of PCFs have been considered. The mechanism for trapping light in the fiber core is explained. The use of the wave methods for electromagnetic field analysis is discussed. The application of variation principles and weighted residual methods is shown. The advantages of the finite element method (FEM) are indicated. The vector FEM for obtaining the modes in photonic crystal fibers is considered.

This paper presents the calculation of the stress and stability of a third-cycle module of a steam boiler during the lifting process. A steam boiler is a key element of a cogeneration plant, so all calculations are performed according to prescribed standards. Before the numerical analysis of the steam boiler, the characteristics, components and function of the boiler are described, as well as the required standards. The 3D model of the boiler was created using the Abaqus/CAE 2016 program package according to the manufacturer’s technical documentation. Using the finite element method, the stresses and stability during lifting of the boiler from the horizontal and vertical positions were calculated and presented. It was found that when lifting from a horizontal position, the structural stress values of the main elements do not exceed the allowable values. On the other hand, when lifting from a vertical position, the stresses exceed the allowable values. In this case, the connection point between the lug and the profile was checked and analytically dimensioned. The obtained values of the stability analysis of the boiler module are satisfactorily defined and there is no risk of buckling in both cases of lifting. The boiler conforms with the standard and fulfils the requirements handed over to the engineer.

This paper shows the approach of submodeling in finite element analysis in process of designing the horizontal tank for storing petroleum products. Those kinds of tanks are made at exact standards or slightly altered by customers’ demands. Before the numerical analysis of the tank, the tank standards are described as well as numerical analysis. In the paper, the methods which will be used in obtaining solutions by finite element method were described. 3D finite elements have been used for numerical analysis. After getting the results of full tank model meshed with 3D tetrahedral final elements, the technique of submodeling has been used to achieve more accurate results in critical locations of the tank. In the final aspect, result analysis was conducted, where the results were confirmed so that the tank complies with the standard and meets all the criteria given to the designer.

The main aim of this paper is to analyze seismic action influence on the pressure parts of the watertube steam boiler construction. Design of the structures in earthquake areas according to Eurocode 8 (EN 1998-1) has been explained and performed on pressure parts construction of one watertube steam boiler. Using the finite element method, reaction forces in the supports, which occur under the influence of boiler weight and during the earthquake in the Abaqus / CAE 2016., have been calculated. At the end, the comparison of the results is shown and analysis of the results is given. Comparison of the European standard EN 1998-1: Design of structures for earthquake resistance and Turkish TEC-07: Turkish Earthquake Code in analysis of the watertube steam boiler is also done, in order to determine whether structures analyzed by EN 1998-1 can also be built on the territory of Republic of Turkey.

The development of new technological methods of SPD for the production of mass production with improved properties due to the deep grinding of the original structure is an important task. The purpose of this work was to study the active bending to grind the structure and create promising, for operational use, gradient structural states in long rods of copper grade M1. Active bending was performed using an extruder according to the “Conform” scheme. The results of the analysis stress-strain state is using computer simulation and structures using optical microscopy. It is established that the active bending method provides over four processing cycles high strain accumulation (e = 3-4) and formation subgrained- structure UFG type.

This study presents to determine the contact stress in rolling bearings by using analytical and numerical method. Analytical solution is obtained by using Hertizan contact theory. Obtained analytical solution by this theory require comparison with the numerical calculations to obtain more accurate results for contact problems. Because of that the same problems are also examined by using finite element method. The geometry of the model being studied gives different type of contact configurations such as a point or line of contact. In cylindrical roller bearing the contact form is line contact and for the ball bearing the contact characteristic is point contact. High stress occurs on both of these two contact areas. Contact stress causes elastic or plastic deformation and the contact area will change depending on the magnitude of the contact stress. Therefore, it is really important to calculate more accurate stress at the contact area.

In this study, a 3-Dimensional finite element simulation of a braking cycle including braking and cooling steps is presented. In order to induce thermal stresses, thermo-mechanical material behaviour and interactions between pad and discs are considered in the simulation. The results reveal that compressive and tensile stresses are happening in the braking and cooling steps respectively. Cyclic tensile stresses in the disc of heavy trucks would lead to the initiation of superficial radial cracks in them. The occurrence of hot spot phenomenon in the discs are also observed and discussed thoroughly. The proposed model could be utilized to estimate fatigue life of the braking discs in the automobiles and heavy vehicles..

In this paper, in order to dimension the position and the number of vertical reinforcement, several numerical linear static simulations of bending circular manhole cover of ductile cast iron (grade EN-GJS-500-7) with 600 mm diameter are performed. The analysis of displacement and stress using the finite element method in the software package Autodesk Simulation Mechanical were conducted. Verification of numerical results for the solution of thin circular plate was performed with analytical bending solutions. After checking the numerical procedure on the thin circular plate, two circular vertical reinforcements were added on the underside: internal and external. Numerical simulations investigated the influence of the inner circular reinforcement position on the strength of the circular manhole cover, while equivalent stresses followed by energy theory of strength (von Mises) were monitored. Since maximal equivalent stresses remain on the plate by varying the position of the inner circular reinforcement, simulations with added radial reinforcements are performed. Finally, by optimizing the number of radial reinforcements, the optimum plate design is chosen.

This paper investigates stress state in connection of pipes with flat ends used in pressurized pipelines and steam boiler connections. Flat ends are designed according standard EN 12952-3 and later numerically checked using linear elastic material model. These analyses showed areas with increased stress. Therefore, additional analyses were performed using linear elastic-ideally plastic material. The maximal pressure loads are obtained for series of pipes with flat ends and compared to calculated results according EN 12952-3 norm.