Technical Transactions iss. 5. Mechanics iss. 1-M

Technical Transactions iss. 5. Mechanics iss. 1-M

Type: Collection of magazine numbers
Release date

Collection items (52)


Strategy of maintenance system in industrial company

Žilka, Miroslav
Article
2013
This paper introduces the main conclusions of the doctoral thesis “Strategy of maintenance system in industrial company”, which focuses on improving of economic efficiency of the maintenance system by selecting the appropriate maintenance strategy for production machines. In the paper I characterise outputs of the survey, which focuses on characterization of maintenance management level, maintenance cost control and allocation level and range of modern maintenance management tools (Computerized Maintenance Management Systems = CMMS) utilization in industrial enterprises in Czech Republic. This article also deals with proposed methodology for selecting the appropriate maintenance strategy and with the brief characteristic of the model MAM (Maintenance Analytical Module), which was developed as a decision support tool for maintenance managers.

Biometric watermarking for medical images – example of iris code

Wójtowicz, Wioletta
Article
2013
This paper presents a preliminary investigation on medical image watermarking using biometric watermarks. The goal is to elaborate simple watermarking system based on discrete wavelet transform (DWT) decomposition and binary iris code insertion. The performance of proposed algorithm is evaluated by Hamming distance between embedded and extracted iris code.

From concept to product – application of Inventium suite system in the design new technology of sink stamping process

Woźniak, Dawid, Hojny, Marcin, Głowacki, Mirosław
Article
2013
This paper shows example results of computer simulations supporting the production process of sink. Design and verification of deep drawing process and tools design were carried out using finite element models implemented in Inventium Suite. Wrinkling and fracture of the material were the main phenomena subjected to the investigation using numerical analysis. A number of computer simulations were carried out in order to eliminate defects and analyze the shape of the final product.

Computer aided of experiments determining the characteristics of cutting steel deformed at high temperatures

Woźniak, Dawid, Głowacki, Mirosław, Hojny, Marcin
Article
2013
The main goal of the paper is modelling of phenomena accompanying the steel subjected to deformation in very high temperature. Analysis of the phenomena in solid surface part and semi-solid core is necessary due to inhomogeneity of material properties in both the zones of the sample. Experimental basis of the work were TESTS done in IMZ Gliwice using Gleeble 3800 physical simulator. The interpretation of the tests was done using Def_Semi_Solid software. This program allows the numerical analysis of steel behaviour during deformation of axial-symmetrical samples at very high temperatures. The paper presents the comparison of experimental and numerical results.

Research study of state-of-the-art algorithms for flexible job-shop scheduling problem

Wojakowski, Paweł, Warżołek, Dorota
Article
2013
The paper discusses various approaches used to solve flexible job-shop scheduling problem concentrating on formulations proposed in the last ten years. It mainly refers to the applied metaheuristic techniques which have been exploited in this research area. A comparison of presented approaches is attempted, some concluding insights are highlighted. Finally future research directions are suggested.

Some aspects of visual management systems applied in modern industrial plant

Wojakowski, Paweł
Article
2013
The paper describes the main features of visual management systems applied to track production state inside manufacturing cells. The description is restricted to the class of the systems called electronic andon system. The way of gathering data from manufacturing cell about process performance is depicted. Integration of electronic andon with ERP systems is presented.

Regulation of flow rate generated by cross flow fan with use of internal vane. Experimental and numerical results

Stacharska-Targosz, Jolanta
Article
2013
In this paper the problem of volumetric flow rate regulation is considered. The change of angular position of an element mounted axially inside of the cross flow fan impeller creates different aerodynamic performances: Ψt = f (φ), Ψs = f (φ) at the same rotational speed and in consequence the qualitative diversification of fan operation is obtained. It gives possibility to use a cross flow fan for several applications depending on an actual requirement respecting to volumetric flow rate or pressure coefficient. The shape of inner element as well as its angular position have an important influence on the flow structures so a method of volumetric flow rate control without necessity of rotational speed change is proposed. This way of cross flow fan flow rate control, commonly made with use of frequency converter, seems to be more effective for reduction of an energy consumption and gives an evident economic advantage.

Evaluating the influence of generation methods on the quality of the smart designs of experiment

Skowronek, Andrzej
Article
2013
This paper presents results of computer simulation made to evaluate how the quality of the smart designs of experiment depends on the methods of generating. The quality of smart designs was evaluated by comparing the known values of special testing functions simulating the real research object and approximated values predicted by neural networks trained with the sets based on smart designs of experiment. The results suggest the possibility of significant reducing the number of experiments runs using studied smart designs.

Flow forces acting on the spool of directional control valve

Rajda, Janusz, Lisowski, Edward
Article
2013
This paper presents a method with the use of CFD analysis for calculating the forces acting on the spool during the flow of working liquid stream through the electro-hydraulic pilot operated directional control valve. The liquid stream flowing through the directional valve causes hydrodynamic response according to the principle of conservation of momentum. Liquid pressure acting on the spool surface affects the forces balance of valve spool as well. An object of the research is the pilot operated directional control valve WEH22 type with flow rate up to 450 dm3/min. For the analysis ANSYS/Fluent software was used.

Analysis of switching time for pilot operated directional control valve

Rajda, Janusz, Lisowski, Edward
Article
2013
The paper presents an analysis of switching time for pilot operated directional control valve [1–3] in a typical hydraulic system, in which the actuator is a hydraulic cylinder. A mathematical model has been built which contains equations of motion for the valve and actuator components, the balance of fluid flow, flow through the gap, and the principle of conservation of momentum and the flow curves of pressure relief valves [6, 8]. The system of equations is solved by fourth-order Runge-Kutta method. A survey to find minimal switching time has been conducted [4]. Positive overlap value, the coefficient of its movement resistance and control pressure value have significant impact on the switching time in the tested valve.