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1
Content available Simplified estimate of fatigue damage based on dynamic analysis
Dekys V., Kriska P, Lietava L., Kopas P., Stalmach O.
Zeszyty Naukowe. Transport / Politechnika Śląska
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2018
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z. 99
15--23
EN
The article presents a procedure for vibration analysis of the device based on measured data in simulated operating modes. Subsequently, the criterion of fatigue damage is formulated because this mechanism can be induced or accelerated by recognized operating deflection shapes. The criterion is used to select an optimal set of control device parameter values, which control each device’s operating modes and transitions between these modes and affect the excitation of the frame vibration due to possible shocks in the system. The criterion is formulated based on the vibration displacement processing from these dynamic measurements, the modified Goodman and Palmgren-Miner rules, and the results of static computational analyse. This criterion compares the effect of damage to the modes that control these sets of parameters, while the selection of the optimal control set is performed. At the end of the article, the limitations resulting from the simplifications used are described. The application of this procedure is also useful, for example, when further data are obtained by subsequent experimental stress-strain analysis methods and when we want to reduce the number of possible operating modes by which we carry out subsequent measurements among the most damaging modes.
2
Content available Parallel and distributed implementation of optimization algorithms in fe analyses
Handrik M., Vasko M., Kopas P.
Zeszyty Naukowe. Transport / Politechnika Śląska
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2012
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z. 76
67--74
EN
The aim of this paper is analysis of optimization algorithms in terms of their possible solutions in parallelization and distributed computing systems. Main goal is using of evolutionary algorithms and implementation of parallel algorithms. As the software platform for application of distributed optimization algorithms is using software package BOINC. For evaluation of the objective function is used FEM program ADINA.
PL
Artykuł analizuje algorytmy optymalizacyjne pod kątem ich możliwości obliczeń równoległych oraz rozproszonych systemów obliczeniowych. Ukierunkowany jest przede wszystkim na algorytmy ewolucyjne oraz ich implementację równoległą. Jako platforma softwarowa do zastosowania rozproszonego systemu obliczeniowego algorytmu zostało zastosowane oprogramowanie pośredniczące BOINC. W celu oceny funkcji docelowej został zastosowany w MES program ADINA.
3
Content available remote The Vector Autoregressive Moving Average Models as a Tool for Adaptive Identification of Structures Dynamic Systems
Leitner B., Kopas P.
Machine Dynamics Research
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2010
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Vol. 34, No. 4
32-41
EN
The paper deals with one of possible ways of an identification of stochastically loaded mechanically structures. The purpose of this approach is to find an algorithm of a forecasting control of their working in real working conditions. It deals with a proposal of an application of vector time series moving average models (VARMA). Their parameters are possible to determine using the nonlinear modification of the least squares method. The paper contains a theoretical principle of problems solved and a description of a real testing methodise.
4
Content available remote Structure Analysis and Fatigue Life Prediction of the Large Scale Handling Device
Vaško M., Handrik M., Sága M., Kopas P., Vaško A.
Machine Dynamics Research
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2010
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Vol. 34, No. 4
102-109
EN
The goal of the paper was to present predictions of the fatigue lifetime of the large scale welded construction. The structural modelling and the stress-strain analysis were realised using finite element method. To determine the fatigue damage or the residual lifetime the "von Mises" equivalent stress was compared with normal stress from classical S-N (Wohler) curve (Fig. 5). The results were compared with reality, i.e. with measuring on real equipment. Distribution of the critical points confirmed consensus between both approaches (computational and experimental).
5
Content available remote Some Notes on Analysis of Bending and Torsion Combined Loading
Jakubovičová L., Sága M., Kopas P., Handrik M., Vaško M.
Machine Dynamics Research
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2010
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Vol. 34, No. 3
97-105
EN
The purpose of this paper is to present procedure of stress and strain distribution analyses at the testing sample. Experimental device is designed for combined bending - torque loading. Structural design of the equipment allows loading by constant turn of the clamping parts. The stress and strain magnitude in test sample depends on the shape and material sample. To obtain the exact solution of the stress and strain values is generally very difficult and therefore for their specification was used FE method and experimental measurement using optical system ARAMIS.
6
Content available remote Identification of the BW Hysteric Material Model Parameters and Application on Energy Fatigue Curve
Sága M., Vaško M., Kopas P., Jakubovičová L.
Machine Dynamics Research
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2010
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Vol. 34, No. 4
79-87
EN
The paper deals with the numerical computational tools application for the hysteretic curve identification using Karray-Bouc (KB) and Ramberg-Osgood (RO) material models. The Karray-Bouc model parameters was determined from Ramberg-Osgood model and Manson-Coffin curve parameters. Using special Matlab's procedures we can calculate dissipative (hysteretic) energy density per cycle and express Manson-Coffin curve in energy version.
7
Content available remote Computational Simulations of Stress Distribution in Surrounding of Graphite Particles
Kopas P., Handrik M., Jakubovičová L., Sága M.
Machine Dynamics Research
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2010
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Vol. 34, No. 3
115-123
EN
The goal of the paper has been to present a computational simulation of the stress distribution in the surrounding of graphite particles. There were designed four algorithms for creation fields with random shape of graphite particles. Based on quantitative and qualitative evaluating of these algorithms it can be seen that the only appropriate field generation procedure with graphite particles is algorithm call "diffusion of carbon". Main objective of statistical processing of analysis result is determination of the 99.8% quantile stress concentration function for one or more graphite particles.
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