• Seismic action influence on the pressure parts of the watertube steam boiler construction

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 5, pg(s) 210-213

    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.

  • Gradient structure and methods for their preparation

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 3, pg(s) 147-148

    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.

  • Finite elements method modelling of rolling bearings

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 2, pg(s) 62-65

    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.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    THREE-DIMENSIONAL SIMULATION OF THERMAL STRESSES IN DISCS DURING AN AUTOMOTIVE BRAKING CYCLE

    Trans Motauto World, Vol. 3 (2018), Issue 4, pg(s) 158-161

    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..

  • MATERIALS

    OPTIMIZATION OF THE CIRCULAR MANHOLE COVER MADE OF DUCTILE CAST IRON USING FINITE ELEMENT METHOD

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 5, pg(s) 225-233

    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.

  • INNOVATIVE SOLUTIONS

    STRESS AND STRAIN ANALYSIS OF CONNECTION OF PIPES WITH FLAT ENDS

    Innovations, Vol. 6 (2018), Issue 3, pg(s) 102-105

    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.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    IMPROVING BENDING LOAD CAPACITY OF SPUR GEARS WITH INCREASING ROOT RADIUS

    Trans Motauto World, Vol. 3 (2018), Issue 1, pg(s) 7-2

    Gears are one of the most important machine elements in the industry. They are using many areas such as; automotive, energy, aviation, etc. Gears are exposed to higher loads day by day due to the increase in power and speed on the machines. Therefore, the stress values which are occur on the gear root is also increase. These stresses cause to damage on the teeth root. Thus the stress values have to be decrease to design optimum gear body. In this study, the effects of root radius on the gear bending stress are evaluated by using finite element method. At first, gears with standard root radius is investigated both DIN 3990 and finite element method. After the validation of finite element model, the root radius of the gear is taken as parameter. Gears with different root radiuses are analyzed by using finite element method. It is seen that with the increasement of gear tooth radiuses, the root stress is considerably decreased. With increasement of root radiuses the maximum principal stress reduced nearly 20%.

  • DESIGN AND ANALYSIS OF THE HYDRAULIC ARM FOR MOUNTING ON A LIGHT GOODS VEHICLE

    Trans Motauto World, Vol. 1 (2016), Issue 4, pg(s) 19-23

    This paper is focused on numerical analysis of a hydraulic arm for use on a light goods vehicle. The designed arm is used for loading and manipulation with load up to 300 kg. Its load capacity depends on the light goods vehicle to be placed on. Great operability of this mechanism predetermines its wide application, e.g. in construction, transport, business etc. Firstly, analytical calculations of the forces, moments and reactions are introduced. Further, locations and values of the maximum stress in the structure of the designed hydraulic arm are calculated using the FEM software. These results determine the relevant data necessary for correct design functioning of the machine. After carrying out all the analyses and calculations we will be able to determine the safe use of the designed handling machine and put it into operation.

  • TECHNOLOGIES

    FINITE ELEMENT MODELING OF INCREMENTAL SHEET METAL FORMING OF ALUMINUM ALLOY AL 1100

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 8, pg(s) 397-400

    Incremental sheet metal forming has been well-known as one of the flexible methods of forming metallic sheets, suitable for the production of prototypes or small batch sizes. Apprehending the deformation method in forming processes and selection of route parameters to avoid part failure are of vital importance, because marketing needs standard sound parts in a shortest possible time. This paper presents the study on the use of finite element modeling of incremental sheet metal forming of Al 1100 aluminum alloy to investigate the effect of tool diameter and step over on the forming induced stresses, part thickness distribution and forming forces. The results of finite element analysis are compared with experimental data while producing truncated pyramid parts. It has been shown that the developed finite element model is capable of providing reliable results in the prediction of the final thickness of the part, which matches the experimental results with a maximum discrepancy of 8%.

  • TECHNOLOGIES

    COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS OF STRESS-DEFORMATION STATE IN A PIPELINE BRANCH

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 2, pg(s) 36-62

    The subject of this paper is the analysis of stress distribution of the pipeline branch in hydropower. Pipe branches are widely used and very in complexity of the shape. Behaviour of the pipe branch subjected to the internal pressure was analyzed both numerically and experimentally. Analytical stress calculations are limited on the simpler forms of branches, so numerical calculations had to be used. Focus of numerical analysis was on determining critical locations and its values. Strain gauge method was used to measure greatest stress concentrations on the defined locations. Experimental results were very close to numerical calculations. Material used for manufacture of the pipeline branch is NIOVAL 47. This paper can be used as the base for the future researches concerning stress distribution in other branches among the pipeline both numerically and experimentally.

  • MATERIALS

    ABOUT COMPUTER DESIGN OF MACHINE AND EQUIPMENT THE GENERAL MACHINE BUILDING

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 1, pg(s) 11-14

    We grounded the motivation of students to develop and use catalogue in their work. Examples with family planetary reducers are given and the construction of safety over flow valve is discussed as well as its rotor eccentric crusher in mine industry. A 3D model of rotor crusher is presented with the catalogues numbers of crushing and flywheel head. We made computer investigation of repercussion plates of crusher and their static movement. The results are analysed and recommendation are made about improvement of construction. A conclusion about relationship between competitive power of products and quality of training in higher technical education was made.

  • MODELLING OF PRELOAD DISTRIBUTION IN BOLTED JOINTS WITH THE SPIDER BOLT MODEL

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 7, pg(s) 3-5

    The paper is a part of wider research based on the system approach to the problem of modelling and calculations of bolted flange connections. With this approach it is possible to independent consideration of each system’s element in order to find the best model of this element. The aim of this study is to develop a model of the single-bolted joint separated from the bolted flange connection.
    An analysis is conducted for the spider bolt model which is an equivalent model corresponding to the spatial bolt model. The key problem in the case of modelling bolts with the spider bolt model is adequate distribution of the preload on the bolt head. Accuracy of modelling bolts using the spider bolt model strongly depends on the way of this distribution. The effect of preload distribution in the spider bolt model on stiffness values of the element fastened in the bolted joint has been examined. The result of actions described in the paper is proposal distribution of the preload on nodes belonging to the bolt head which guarantees the best effects of spider bolt model application.