Wyniki wyszukiwania - Biblioteka Nauki

1

Contribution to random vibration numerical simulation and optimisation of nonlinear mechanical systems

100%

Sága M. , Vaško M. , Handrik M. , Kopas P.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2019

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tom z. 103

143--154

EN

This study considered the solution of the stochastic vibration of non-linear mechanical systems with Gaussian random excitations. It realised a short review of linearisations techniques in stochastic dynamics mainly with application in the area of truss finite element modelling. The presented method of statistical linearisation is applied to numerical testing. In the second part of the article, the sensitivity analysis of the first two stress statistical moments and structural weight minimising subjected to the random stress constrains presented by mean value and standard deviation was brought to the fore. Cross-sectional areas were used as optimising parameters.

2

The simulation and the experimental verification of the influence of the tig - welding of the aluminium alloy AlMgSi07 on changes of the mechanical properties in comparison with the basic material

100%

Blatnický M. , Kopas P. , Sága M.

Studia i Materiały Informatyki Stosowanej

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2011

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tom nr 4

49--54

EN

The aim of this investigation is to evaluate the influence on fatigue behavior of the welded aluminum alloy AlMgSi07. For the experimental measurement of fatigue of these welds, it is needed to analyse all the changes, which will occur in the weld material in comparison with the basic material. The modern computer simulation and the experimental verification are strong tools for achievement of the required results, for instance a change of the structure, residual stress, a range of the heat affected zone, a deformation of the workpiece etc.

3

Modeling of multiaxial state of stress and determine the fatigue lifetime for aluminum alloy during cyclic loadingunder in-and-out of phase shift Φ = 0° and Φ = 90

100%

Uhríčik M. , Kopas P. , Sága M.

Studia i Materiały Informatyki Stosowanej

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2011

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tom nr 5

9--13

EN

This article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with the criterions for evaluation of multiaxial fatigue lifetime. The experimental part deals with modeling of combined bending - torsion loading and determining the number of cycles to fracture in region low-cycle and high-cycle fatigue and also during of loading with the sinusoidal wave form under in phase Φ = 0° and out phase Φ = 90°.

4

Multiaxial fatigue experimental analysis of 6063-T66 aluminum alloy of the base material and the welded material

88%

Uhríčik M. , Kopas P. , Palček P. , Oršulová T. , Hanusová P.

Quality Production Improvement - QPI

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2019

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tom Vol. 1, Iss. 1

334--341

EN

This article deals with determining of fatigue lifetime of aluminum alloy 6063-T66 during by multiaxial cyclic loading. The experiments deal with the testing of specimens for identification of the strain-life behavior of material, the modeling of combined loading and determining the number of cycles to fracture in the region of low-cycle fatigue. Fatigue tests under constant amplitude loading were performed in a standard electromechanical machine with a suitable gripping system. Based on the experimental results the fatigue design curves are compared to the fatigue data from the base material and the welded material and also multiaxial fatigue models, which are able to predict fatigue life at different loads.

5

Influence of a Directional Dependenceon Mechanical Properties of Composites Reinforced with Chopped Carbon Fibre Produced by Additive Manufacturing

75%

Majko J. , Handrik M. , Vaško M. , Sága M. , Kopas P. , Dorčiak F. , Sapietová A.

Archives of Metallurgy and Materials

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2023

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tom Vol. 68, iss. 2

455--461

EN

Progress in the industry is accompanied by the development of new materials and more efficient technological production processes. At present, additive production is becoming very attractive in all industries (research, development, production), which brings a number of advantages compared to subtractive methods (customization, production speed, control of material properties by users, etc.). The main advantage of 3D printing is the controlled deposition of material in defined places. Instead of demanding manual labour, fully automated production via computers leads to the manufacturing of complex components from materials whose production in conventional ways would be problematic or even impossible. Because these are new technologies, the main direction of research at present is to identify the basic physical properties of these materials under different types of loading. The main goal of this article is to observe the dependence of the behaviour of the extruded material (thermoplastic reinforced with chopped carbon fibre) on the printing parameters (thickness of the lamina, the orientation of the fibres of the printed material, etc.). Based on published scientific works, it appears that these settings have a significant impact on the achieved physical properties. This is the reason why the authors decided to analyze the influence of these parameters on the basis of processed data from experimental measurements of mechanical properties in the MATLAB program. As this is FFF printing, an essential condition is to identify and specify the directional dependence of the behavior of the printed material. This physical phenomenon is a necessary condition for gradual knowledge for the purposes of a subsequent mathematical description of the material properties. According to the authors, for the purposes of modeling these materials in FEM-based programs, it is essential to define the directional dependence in the plane of the lamina.