Communications - Scientific Letters of the University of Zilina, 2014 (vol. 16), issue 3A

Articles

Articles

Mobility of Multibody Systems in Terms of their Incorrectness

Alzbeta Sapietova, Milan Saga, Alexandr Shimanovsky, Milan Sapieta

Communications - Scientific Letters of the University of Zilina 2014, 16(11):6-12 | DOI: 10.26552/com.C.2014.3A.6-12  

The paper presents examples of incorrectness from the point of view of body and Multibody System (MBS) kinematics. This incorrectness should be kept in mind when modeling Virtual Prototypes (VP) of MBS. During the analysis or synthesis of MBS it is necessary to correctly determine the degree of freedom (DOF) of mechanisms in order to properly design the mechanism. The basic relation for the DOF computation does not include parameters such as special dimensions of links or their mutual configuration and geometric constraints. In many cases, these issues require individual approach, i.e. by analyzing the properties of incorrect MBS to identify the causes...

Numerical Algorithm for Beam Residual Stress Identification

Milan Saga, Milan Vasko, Peter Kopas, Lenka Jakubovicova

Communications - Scientific Letters of the University of Zilina 2014, 16(11):13-18 | DOI: 10.26552/com.C.2014.3A.13-18  

The goal of the paper is the numerical study of the original hysteresis computational material models and their application in beam's bending theory. The paper presents the chosen differential material models and approaches based on step by step solution respecting the elastic and plastic conditions. In the centre of authors´ interest is the numerical method study of the plastic zones identification or study of residual stresses distribution in the beam's cross-section. The results obtained from new MATLAB's programs are compared with FEM models in ADINA.

Effective Finite Element Solution and Post-Processing for Wide Load Spectrum

Marian Handrik, Milan Vasko, Peter Kopas, Milan Saga

Communications - Scientific Letters of the University of Zilina 2014, 16(11):19-26 | DOI: 10.26552/com.C.2014.3A.19-26  

This paper presents a computational algorithm allowing the efficient use of high-performance computing resources to solve nonlinear problems of continuum mechanics using FEM. The algorithm is suitable for solving static problems and tasks of estimating lifetime of structures in cases where the load is defined by the load spectrum. The complexity of the problem increases significantly in the case of nonlinear problems. The principle of the stress superposition cannot be used in that case. For each loading mode a separate FE analysis must be made. A quick and efficient procedure for evaluating the results of mentioned analysis for the static calculation...

Development of Test Stand Prototype for Rail Vehicles Brake Components Testing

Juraj Gerlici, Tomas Lack, Jozef Harusinec

Communications - Scientific Letters of the University of Zilina 2014, 16(11):27-32 | DOI: 10.26552/com.C.2014.3A.27-32  

The paper deals with the new RAILBCOT test stand building reasons explanation. A project features definition is described. There is possible to perform the railway wheel tread profiles wear research under the rail vehicle in operation conditions simulation. This simulation is possible to execute on the test bench. An important feature of the research is the equivalent conicity change analysis. The paper outlines the stand operation principles a main structure components design and components parameters specification, the tests control, data acquisition and data assessment.

Wheel/Rail Tangential Contact Stress Evaluation by Means Of the Modified Strip Method

Tomas Lack, Juraj Gerlici

Communications - Scientific Letters of the University of Zilina 2014, 16(11):33-39 | DOI: 10.26552/com.C.2014.3A.33-39  

The article deals with the way of calculating tangential stresses over non-elliptical contact patch where Kalker's simplified method FASTSIM can be used advantageously. This method named FASTSTRIP is adapted for non-elliptical contact area calculated by means of the Strip method. This method is almost as quick as FASTSIM and the results are similar to the CONTACT results. This method may be useful for rail vehicles in track dynamics computation.

Evolution of Maintenance Systems of Passenger and Freight Wagons from the ECM Certification Point of View

Peter Zvolensky, Vladimir Stuchly, Juraj Grencik, Roman Poprocky

Communications - Scientific Letters of the University of Zilina 2014, 16(11):40-47 | DOI: 10.26552/com.C.2014.3A.40-47  

RCM and ECM are abbreviations seemingly the same though the meaning is different. However, they have lot of common as the both are aimed at increased reliability of operation and minimising risk. RCM stands for Reliability Centred Maintenance and ECM stands for Entity in Charge of Maintenance, thus maintenance is the common term for both. Indeed, maintenance is a key for increased safety and reduced risk. The paper presents basic principles and theory behind the RCM - an advanced maintenance concept with its origin in aviation and consequently applied in industries connected with high level of risk, such power generation, etc. The ECM certification...

Mathematical Model for Prediction of Biomass Ash Melting Temperature using Additives

Michal Holubcik, Jozef Jandacka

Communications - Scientific Letters of the University of Zilina 2014, 16(11):48-53 | DOI: 10.26552/com.C.2014.3A.48-53  

Some types of biomass ash have low ash melting temperature which can result in various problems in combustion processes. Ash slags and sinters can avoid heat transfer in heat exchangers, which can also cause corrosion of heat transfer surfaces. One of the ways of burning fuels with low ash melting temperature is to use additives. Ash melting temperature can be determined in a laboratory on the basis of standard STN ISO 540. Meltability of ash is characterized by the physical state of ash occurring during the heating process under well-defined conditions in the furnace. Experimental determination of ash melting temperature is quite expensive. In this...

Criterion Equations of Heat Transfer for "N" Horizontal Pipes One above Another at Natural Convection in Linear Method of Approximation

Andrej Kapjor, Jozef Huzvar, Branislav Ftorek, Martin Vantuch

Communications - Scientific Letters of the University of Zilina 2014, 16(11):54-61 | DOI: 10.26552/com.C.2014.3A.54-61  

The aim of the analysis of heat and fluxional pipe fields"n" pipes one above another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. For creating criteria-relation and calculating the Nusselt number for "n" tubes one above the other were used computational data from Ansys-Fluent software and criterion equations for a single tube. Based on the heat transfer analysis of a single horizontal tube will be used criterial equation for calculating the Nusselt number according to Morgan. For themselves derive...

Condenser Optimization of Heat Pipe

Radovan Nosek, Stanislav Gavlas, Richard Lenhard, Veroslav Sedlak, Havard Mollerhagen Arvesen

Communications - Scientific Letters of the University of Zilina 2014, 16(11):62-66 | DOI: 10.26552/com.C.2014.3A.62-66  

Construction of heat exchanger assembly has important role for efficient operation of energy systems. Within this assembly a heat pipe is utilized for heat transfer. The condensation part of the heat pipe is situated on top of the heating zone. The device placed in the heating zone is condenser which is used for efficient heat transfer from one medium to another. The thermal oil is used as cooling medium in the condenser. This paper analyzes the effect of different operation conditions of thermal oil to thermal performance. From the collected results it is obvious that the larger mass flow and higher temperature cause better thermal performance and...

The Vibrodiagnostics of Damaged Gears of Planetary Gearboxes

Lubos Kucera, Tomas Gajdosik, Jan Bucala

Communications - Scientific Letters of the University of Zilina 2014, 16(11):67-73 | DOI: 10.26552/com.C.2014.3A.67-73  

This article deals with description of a diagnostic device used at the Department of Design and Machine Elements at the University of Zilina which has been built in order to measure, diagnose and evaluate gearbox faults by vibrodiagnostics. The article describes methods and damage creation process for tested gearboxes. Evaluation of different faults is also processed in this article as well as description of comparative measurements between real and artificially created pitting. Comparison of all measured data with SPM methods is also included.

Dynamic Analysis of a Rolling Bearing Cage with Respect to the Elastic Properties of the Cage for the Axial and Radial Load Cases

Robert Kohar, Slavomir Hrcek

Communications - Scientific Letters of the University of Zilina 2014, 16(11):74-81 | DOI: 10.26552/com.C.2014.3A.74-81  

The aim of this paper is to detail the creation of a large tapered roller bearing model with flexible body cages in the Adams program suite for subsequent dynamic analysis and to obtain information about kinematic and dynamic relationships of steel and plastic cages under various operating conditions. The bearing model was made to closely resemble its real-life counterpart, which allows us to estimate load conditions, dynamic conditions of individual bearing parts and interactions between them.

Experimental and Numerical Analysis of Crack Propagation in Light Composite Materials under Dynamic Fracturing

Michal Petru, Jozef Broncek, Petr Lepsik, Ondrej Novak

Communications - Scientific Letters of the University of Zilina 2014, 16(11):82-89 | DOI: 10.26552/com.C.2014.3A.82-89  

Research and analysis of mechanical properties including crack propagation in a light composite material is currently very important because composite structures are gradually becoming an alternative material that allows a significant reduction in the weight of car parts. This leads to an increase in efficiency in transport vehicles. This article describes experimental as well as model analysis of damage to composite textiles during dynamic fracturing. The obtained information provides an approach to the complex problem of crack propagation in composite textiles intended for use in car seats. This is especially important from the point of view of safety,...

Studying the Implementation of Potentiometric Methods for the Detection of Cracks in Renovation of Forging Tools

Jozef Pilc, Michal Derbas, Miroslav Janota, Mario Kosut

Communications - Scientific Letters of the University of Zilina 2014, 16(11):90-95 | DOI: 10.26552/com.C.2014.3A.90-95  

Mass production using forging tools leads to an enormous increase in the consumption of forging tools and the need for rapid and flexible tool renovations. A major shortcoming in the renovations is the failure to identify cracks propagating from the surface towards the core of the basic components. Forging tools made from special tool steels are highly cost-intensive. The main cost component is the price of the material, heat treatment and other chemical-heat treatment surfaces. This is the main reason why it is necessary to think about renovation at the design stage, in case of the need for repairs. An important factor in the renovation process is...

Machinability of Nano-Structured Biomaterials for Dental Implants

Dana Stancekova, Jan Semcer, Jozef Holubjak, Mario Drbul

Communications - Scientific Letters of the University of Zilina 2014, 16(11):96-100 | DOI: 10.26552/com.C.2014.3A.96-100  

High quality materials are characterized by increased wear resistance, high strength and hardness, abrasive wear resistance, heat and creep resistance. Due to these properties some materials are considered as hard to machine. This group of materials includes biocompatible materials used for manufacturing implants from commercially pure titanium TiGr2, TiGr5, nano-structured commercially pure titanium nTi and volume-formed titanium alloy TiNbTa. Materials were tested by milling operations with different cutting parameters and force of cutting monitoring.

The Approaches of Advanced Industrial Engineering in Next Generation Manufacturing Systems

Branislav Micieta, Vladimira Binasova, Michal Haluska

Communications - Scientific Letters of the University of Zilina 2014, 16(11):101-105 | DOI: 10.26552/com.C.2014.3A.101-105  

The article deals with new approaches to the development trends in the advanced industrial engineering in manufacturing systems. The authors emphasize the need for integration of advanced industrial engineering in next generation manufacturing systems, which responds to new trends of production, innovation and advanced technology. This integration represents a sustainable development so that humanization of work is increased, more effective use of natural and energy resources are achieved and production costs are reduced. Trends in the products manufacturing must meet both industrial engineering as well as production management. The development trends...

Order Picking Using Augmented Reality

Martin Krajcovic, Gabriela Gabajova, Branislav Micieta

Communications - Scientific Letters of the University of Zilina 2014, 16(11):106-111 | DOI: 10.26552/com.C.2014.3A.106-111  

This article examines the problem of application of augmented reality in terms of picking goods in static systems with the deployment of a man (systems "goods to man"). Article describes a comprehensive methodology for the use of augmented reality in the process of picking starting from the preparation of input data, through optimizing the movement of workers in the warehouse, to actual worker navigation using augmented reality. The problem was solved on the authors´ workplace and the proposed solution has been verified in the experimental workplace built under the concept of ZIMS (Zilina Intelligent Manufacturing System) which is developed at the...

Innovation Performance of Organization

Branislav Micieta, Martin Gaso, Martin Krajcovic

Communications - Scientific Letters of the University of Zilina 2014, 16(11):112-118 | DOI: 10.26552/com.C.2014.3A.112-118  

Globalization has confirmed that the competitive ability of organizations is conditioned by the successful development of innovations. Innovation management and development of innovative potential of organizations are becoming a scientific problem, since the existing approaches in this area do not have satisfactory results. The paper presents a new approach to enhancing innovation performance of the organization that is built on a systematic examination of possible innovation potential of the organization and purposeful creation of a suitable innovative environment in the organization.

Possibilities of Eliminating the Higher Amount of Iron in Secondary AlSi7Mg0.3 Alloy by Chrome

Dana Bolibruchova, Lukas Richtarech, Wladyslaw Orlowicz

Communications - Scientific Letters of the University of Zilina 2014, 16(11):119-123 | DOI: 10.26552/com.C.2014.3A.119-123  

This paper deals with influence on segregation of iron based phases by chrome. Iron is one of the most common impurities that could be found in Al-Si alloys. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition of some other elements that affect the segregation of intermetallics in less harmful type. Realization of experiments and results of analysis show new perspective on solubility of iron based phases during melt preparation with higher iron content and influence of chrome as iron corrector of iron based phases. It could be concluded that higher amount of chrome causes...

Simulation of Roundness, Hardness and Microstructure of Bearing Rings with Thin Cross Sections by Using Sysweld

Peter Fabian, Peter Jankejech, Martina Kyselova

Communications - Scientific Letters of the University of Zilina 2014, 16(11):124-129 | DOI: 10.26552/com.C.2014.3A.124-129  

The roller bearing is a component which helps to reduce friction on relative rotational or sliding movements of the machine parts. Nowadays, there are many kinds of rolling bearings whose production is constantly improving due to increasing demands on the mechanical properties and durability. An important and necessary step in the production of rolling bearings is the heat treatment. Technological heating process must be created rationally for the required mechanical properties such as hardness, toughness and also dimensional accuracy all with respect to the economic efficiency. Because of the economical demands, simulation software is increasingly...

Experimental Measurements and Numerical Simulation of Bridge Construction Welding at Low Temperatures

Radoslav Konar, Marek Patek, Milos Mician

Communications - Scientific Letters of the University of Zilina 2014, 16(11):130-135 | DOI: 10.26552/com.C.2014.3A.130-135  

This article describes experimental measurements and welding simulation by welding of bridge construction with thickness 30 mm. The welded bridge plate was made from steel S355. Welding was carried out at low ambient temperature. Welding parameters and temperature cycles were measured during welding. Deformations of welded construction were obtained using optical system TRITOP before and after welding process. Experimental results except for deformations were used as boundary conditions for FEM simulation in SYSWELD. Temperature cycles, angular deformations and residual stresses were computed. The values of computed and measured angular deformations...

Statistical Analysis of Wind Speed Data Based on Weibull and Rayleigh Distribution

Ivana Pobocikova, Zuzana Sedliackova, Jan Simon

Communications - Scientific Letters of the University of Zilina 2014, 16(11):136-141 | DOI: 10.26552/com.C.2014.3A.136-141  

In this paper the wind speed data from Meteorological observatory Bratislava-Mlynska dolina were statistically analyzed. The data were analyzed based on Weibull and Rayleigh distribution. The distribution parameters were estimated using maximum likelihood method. The both distributions were compared for their performance using the coefficient of determination and the root mean square error. The results indicate that the better performance can be obtained by the Weibull distribution.

Numerical Finite Element Method Homogenization of Composite Materials Reinforced With Fibers

Daniel Riecky, Milan Zmindak, Zoran Pelagic

Communications - Scientific Letters of the University of Zilina 2014, 16(11):142-147 | DOI: 10.26552/com.C.2014.3A.142-147  

The paper presents the micromechanical modelling of fiber-reinforced composites in order to determine elastic properties of the homogenized material. For this purpose implementation of homogenization theory was required and analyses were performed. The polymer matrix of three-dimensional representative volume element (RVE) of the composites is modelled by the finite element method (FEM). Software for homogenization of material properties uses direct homogenization method which is based on volume average of stresses in the RVE. Homogenization of composite plate is performed by linking MATLAB and ANSYS software. Calculated elastic properties of the homogenized...

Approach to the Problem of Bio-Inspired Robotic Gripper Designing

Darina Kumicakova, Zdenek Konecny

Communications - Scientific Letters of the University of Zilina 2014, 16(11):148-153 | DOI: 10.26552/com.C.2014.3A.148-153  

The article with its content belongs to the field of bio-inspired robotics. This main focus is aimed at the problem of a specialised human-like robotic gripper designing. The article presents our approaches to solution of the chosen problems of multifunctional robotic grippers designing on the example of a proposed 3D model of three-fingered bio-robotic gripper. Attention is devoted to utilisation of CAD/CAE tools for exploring characteristics of the design using computer simulation.

The Calculation of Inverse Kinematics for 6DOF Serial Robot

Juraj Uricek, Tibor Galbavy, Vladimir Bulej, Peter Durec

Communications - Scientific Letters of the University of Zilina 2014, 16(11):154-160 | DOI: 10.26552/com.C.2014.3A.154-160  

This article deals with the inverse kinematic model of robot devices which was implemented into the simulation software RoboSim designed at the Department of Automation and Production Systems - Faculty of Mechanical Engineering, University of Zilina. Concretely there is shown the technique how to develop the system of equations for serial kinematic mechanism with 6 degrees of freedom (DOFs). Further this software can be used as universal platform for simulation of mechanisms with serial, parallel as well as hybrid kinematic structure. This flexibility can be considered as a main advantage of the software RoboSim. Its specific feature is that there...

Observation of Dynamic Processes on Cutting Zone when Machining Nickel Alloys

Andrej Czan, Michal Sajgalik, Anton Martikan, Jozef Mrazik

Communications - Scientific Letters of the University of Zilina 2014, 16(11):161-168 | DOI: 10.26552/com.C.2014.3A.161-168  

Process models of super alloys and included finite element modelling simulations are important for optimizing the metal cutting process, allowing industry to make parts faster, better, and at less cost. Innovative measurement methods of the process can be used to improve and verify the accuracy of these models. With these methods, there are many sources of error when using empirical or exact methods such as infrared radiation thermography to measure the temperature distribution of the tool, workpiece, and chip during metal cutting. Furthermore, metal cutting presents unique measurement challenges due to factors such as the high magnification required,...

Laser Interferometer Diagnostics of CNC Machine Tools

Jerzy Jozwik, Ivan Kuric, Leszek Semotiuk

Communications - Scientific Letters of the University of Zilina 2014, 16(11):169-175 | DOI: 10.26552/com.C.2014.3A.169-175  

This paper presents diagnostics of selected CNC machine tools performed with XL80 laser interferometer with XC80 environmental compensation unit, temperature sensors and XR20-W rotary axis calibrator, working together with XL80 laser. Furthermore, the paper includes the methodology and results of conducted linear and angular error measurements, which supplied data for further analysis. The conclusion section presents results of conducted experiment. Measurement results were presented in figures, charts and tables.

Data Structures Implementation of the Protocol Step-NC at CNC Machines Programming

Nadezda Cubonova, Ivan Kuric

Communications - Scientific Letters of the University of Zilina 2014, 16(11):176-183 | DOI: 10.26552/com.C.2014.3A.176-183  

Standard STEP-NC (ISO 14649) presents a new model for data transmission between CAD/CAM systems and CNC machines. This standard eliminates the shortcomings of the standard G-code and provides new possibilities in their management. At the Department of Automation and Production Systems, Faculty of Mechanical Engineering, University of Zilina in the framework of the research activities was solved a project for the implementation options of STEP-NC format by programming of CNC machines. This paper presents the results of research solutions which focused mainly on the analysis of standard STEP-NC, a methodology on the model data according to the standard...

Tension Mechanism Dynamic Analysis

Michal Lukac, Frantisek Brumercik, Leszek Krzywonos, Pawel Drozdziel

Communications - Scientific Letters of the University of Zilina 2014, 16(11):184-188 | DOI: 10.26552/com.C.2014.3A.184-188  

The aim of the presented article is to show how to create a mathematical model of the tension mechanism working by a spring motion generation and contacting a rigid body at the end of the motion.

Biodegradation Properties Of Az31 Magnesium Alloy Coated by Dicalcium Phosphate Dihydrate

Filip Pastorek, Miroslav Omasta, Lenka Bukovinova, Pavel Dolezal, Branislav Hadzima

Communications - Scientific Letters of the University of Zilina 2014, 16(11):189-193 | DOI: 10.26552/com.C.2014.3A.189-193  

Biodegradation properties of magnesium and its alloys that can be used for implants are not satisfactory and cause serious problems. These problems can be solved by biodegradable surface coatings. Evaluation of biodegradation process of Mg-3Al-1Zn alloy surfaces after grinding and grinding followed by potential controlled electrodeposition of dicalcium phosphate dihydrate (DCPD) was investigated by electrochemical impedance spectroscopy measurements in this study. The potentiostatic electrodeposition treatment process was performed in water solution of Ca(NO3)2.4H2O, NH4H2PO4 and H2O2. The corrosion process on treated and nontreated samples after various...

Corrosion Properties of Various Copper Pipes Joints

Tatiana Liptakova, Monika Halamova, Ayman Alaskari, Martin Lovisek, Maxim Puchnin

Communications - Scientific Letters of the University of Zilina 2014, 16(11):194-199 | DOI: 10.26552/com.C.2014.3A.194-199  

The paper presents the experimental results of various Cu pipes joint corrosion behavior. Joining of copper pipes used for liquid media transport can be made as demountable and fixed joints. The object is to study corrosion resistance of the joints created by soft soldering, hard soldering and fitting. Corrosion properties were investigated by long-term experiment in two identical experimental devices in stagnant and flowing conditions. The experimental environment was water solution of the 3% NaCl, temperature was kept 20° C for 16 hours and 8 hours 80° C per day. In one of the devices for 8 hours the experimental solution was flowing by the input...

Influence of Tool-Workpiece Interface on Surface Integrity after Turning

Jaroslav Dubec, Miroslav Neslusan, Anna Micietova, Maria Cillikova

Communications - Scientific Letters of the University of Zilina 2014, 16(11):200-205 | DOI: 10.26552/com.C.2014.3A.200-205  

This paper deals with influence of flank wear on decomposition of cutting force in turning roll bearing steel. The decomposition is carried out to evaluate the components of cutting force in the tool-chip as well as tool-workpiece interface. The decomposition enables evaluation of the shear and normal forces in the both interfaces. The results of experiments and the following calculations show that while conditions for chip separation in the tool-chip interface stay nearly untouched due to progressive development of flank wear, mechanical load of machined surface associated with components of cutting forces progressively increases with flank wear....

Ergonomics in Practice and its Influence on Employees´ Performance

Luboslav Dulina, Miroslava Bartanusova

Communications - Scientific Letters of the University of Zilina 2014, 16(11):206-211 | DOI: 10.26552/com.C.2014.3A.206-211  

The article deals with the human performance and the factors that affect job performance. During the performance of work a person is exposed to risk factors which to some extent adversely affect his health. It is necessary to note that two views of the position of man in the process currently prevail in the company. The first one, promoted by particular employers, puts the emphasis on performance increase of workers and productivity growth. The second one view is supported by employees and emphasizes the need for safety of a man and health at work. The aim of ergonomics is currently referred to harmonise these views.