Otakar Bokůvka, Michal Jambor, Libor Trško, František Nový and Barbara Lisiecka
M iková , K. et al . 2013. Int. J. of Fatigue, 55, 33.
S kočovský , P. et al . 2014. Náuka o materiáli. EDIS ŽU v Žiline. (in Slovak).
T rško , L. et al . 2014. Dynamic Stength and Fatigue Lifetime, EDIS ŽU v Žiline.
T rško , L. et al . 2014. Materials & Design, 57, 103.
T rško , L. et al . 2017. J. of Mat. Eng. and Performance, 26, 6, 2784.
U lewicz , R. M azur , M. Production Engineering Archives, No.1, 32.
Gregor Izrael, Juraj Bukoveczky and Ladislav Gulan
Utilisation of Modeling, Stress Analysis, Kinematics Optimisation, and Hypothetical Estimation of Lifetime in the Design Process of Mobile Working Machines
The contribution deals with several methods used in the construction process such as model creation, verification of technical parameters of the machine, and life estimation of the selected modules. Determination of life cycle for mobile working machines, and their carrying modules respectively by investigation and subsequent processing of results gained by service measurements. Machine life claimed by a producer is only relative, because life of these machines depends not only on the way of work on that particular machine but also the state of material which is manipulated by the machine and in great extent the operator, their observance of security regulations, and prescribed working conditions.
Ana Diana Ancas, M. Profire, I. L. Cirstolovean, M. Hornet and G. Cojocaru
The lifetime of glass reinforced plastic pipes is 50 years. Extensive use of this type of pipe in its various applications, led to investigate their behavior in land that anthropogenic or natural causes, shows the different values of pH to neutral. The paper presents experimental results conducted on three samples of a PN SN10000 DN150 PN10 pipe buried in three different types of terrain: neutral, acidic, basic. They were subjected to axial load, measuring the force applied deformation force function. On the basis of the calculation formulas determined rigidity of the pipeline, the deformation speed of 50 mm / min. This concludes the type of land affects the rigidity of the pipe so its length of life decreases to that provided by suppliers in order to be taken compensatory measures in this regard such as choosing a higher class of pressure and stiffness pipeline than those arising discounted. This will allow for long-term value (50 years) in the mechanical characteristics sufficient for safe operation.
Miroslava Ťavodová, Daniela Kalincová, Martin Kotus and Ľubomír Pavlík
/0826/15, scientific peer-reviewed collection, pp. 80-89. ISBN 978-80-228-2920-5.
MÜLLER, M. - HRABĚ, P. 2013. Overlay materials used for increasing lifetime of machine parts working under conditions of intensive abrasion. In Research in Agricultural Engineering, vol. 59, no. 1, pp. 16-22.
STN 01 5084. 1974. Determination of metal material resistance against wear by abrasive cloth. SÚTN Bratislava.
STN 41 4220. 1976 Manganese-chromium steel 14 220. SÚTN Bratislava.
STN EN ISO 148-1. 2017 Metallic materials - Charpy
If the electrons and holes in excess are created in a semiconductor, either by means of light absorption, or using other methods, the thermic balance is disturbed, therefore these electrons and holes should be nullified after the source had been stopped. This process is named recombination. There are three main recombination types: radioactive, Auger and deep energy level recombination. All three are based on the doping concentration to a certain point. The life time is determined using the three recombination processes in semiconductor.
This paper focuses on a better understanding of the process of reflective cracking propagation through the pavement structure. A series of finite element numerical simulations were conducted to investigate the initial stress and strain states in typical semi-rigid pavements with and without reflective cracks under traffic loading. It was assumed that reflective-cracks propagate from the base layer to the pavement surface. The influence of selected parameters, such as the load position, overlay thickness, and subgrade quality on stress and strain concentrations was investigated. The behaviour of the pavement structure under repeated traffic loading was analyzed in terms of ground compaction. The original theoretical model proposed by Prof. Andrzej Sawicki was used to predict the deformation of a pavement subgrade subjected to traffic loading. The damaging effect of cracks appearing in the pavement structure was investigated. It was found that even a single crack in the pavement structure may significantly reduce the pavement lifetime.
The power cables passing through penetration leads to growth of the thermal ageing mechanisms rate. The paper presents the results of the laboratory tests when the real environmental service conditions for penetration are simulated comparison with the result of the thermal computation of the power cables heating and of the temperature influence evaluation of temperature increase of the power cable components on the cable lifetime. For this particular case, a power cable with PVC insulation, we estimated a lifetime decrease about 20 years referring to lifetime (30÷40 years) for location in air.
Michal Šajgalík, Andrej Czán, Juraj Martinček, Daniel Varga, Pavel Hemžský and David Pitela
Machined surface is one of the most used indicators of workpiece quality. But machined surface is influenced by several factors such as cutting parameters, cutting material, shape of cutting tool or cutting insert, micro-structure of machined material and other known as technological parameters. By improving of these parameters, we can improve machined surface. In the machining, there is important to identify the characteristics of main product of these processes – workpiece, but also the byproduct - the chip. Size and shape of chip has impact on lifetime of cutting tools and its inappropriate form can influence the machine functionality and lifetime, too. This article deals with elimination of long chip created when machining of shaft in automotive industry and with impact of shape of chip-breaker on shape of chip in various cutting conditions based on production requirements.
Constance Moretti, Xuyuan Tao, Vladan Koncar and Ludovic Koehl
Using their ability to change their color according to an external stimulation, chromic materials can be used to form a color-changing textile. Electrochromism, more particularly, is a colour change phenomenon caused by the application of an electrical potential. A flexible textile electrochromic device composed of four layers is presented. In order to improve the lifetime of this structure, the electrical performances of the electrolyte layer are studied. A method to measure and calculate the resistance variations of the electrolyte applied on a textile cotton substrate is given. Relations between the electrical performances of the electrolyte and the electrochromic effect of the device are also highlighted.
A Synthetic Method for Examination of Potential Reliability and Safety Level Demonstrated by Technical Facilities During Their Lifetime
The paper presents fundamentals for an innovative method that takes advantage of diagnostic information defined with participation of an expert. (presented as a score of points). Defined number of points is assigned to each signal change, depending on the signal value and the moment when the change occurs, whilst the number of points is preliminary defined by an expert. The proposed innovative method consists in the use of signals represented by the scores to determine combined status equations [3, 5] for parameters of the adjustment control state and technical state (equations 3 and 4) and then parameters of reliability and safety (equations 5 and 6). Such an approach enables continuous monitoring of the reliability and safety states of facilities during their lifetime. The presented approach may prove to be extremely useful as it unambiguously presents wear and tear of the facilities and enables to predict when the facilities should be repaired (overhauled).