Wyniki wyszukiwania - Biblioteka Nauki

1

The use of fractal concept in failure simulation and fracture surface analysis

100%

Davydova M. , Davydov D.

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2005

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tom z. 82

45-52

EN

The concept of fractal geometry has found wide application to describe the morphologic and dynamic complexity of many natural processes or objects. This work presents four examples illustrating the use of the fractal concept in studying different aspects of fracture: (i) the percolation model of failure cluster growth; (ii) the statistical investigation of fracture surfaces; (iii) the modelling of the fracture surface; (iv) the analysis of fracture pattern resulting of glass fragmentation.

2

Effect of milling time and addition of alumina powder on the structural properties and fracture surface of nanocrystalline Al

80%

Razavi Tousi S. S. , Yazdani Rad R. , Salahi E. , Razavi M.

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tom Vol. 27, No. 3

875--884

EN

The effects of milling time and the addition of alumina reinforcement on the structural evolution of Al matrix were investigated. By analysing the cross section of powder, cold welding mechanism for both monolithic and composite powders was studied. Results show that presence of the alumina powder has a marked effect on variation of apparent density, preferred orientation, impurity content and thus lattice parameter of Al by milling time. The reduction of the grain size to the nanometeric scale changes the fracture mechanism of Al particles completely, from dimpled into intergranular, though alumina addition does not seem to have notable influence on the fracture mechanism.

3

Microstructure and Properties Evaluation of Ductile Cast Iron Subjected to Hot Plastic Deformation and Ambient Temperature Compression

70%

Chaus A. S. , Čaplovič Ľ. , Pokrovskii A. I. , Sobota R.

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tom Vol. 68, iss. 2

639--648

EN

The as-cast microstructure of ductile cast iron (DI) was investigated using light microscopy (LM) and SEM techniques. Further the influence of hot plastic extrusion at 1000°C with plastic strain in the range of 20-60-80% on the transformation of the as-cast microstructure and on the mechanical properties was studied. Besides this, the microstructure of DI subjected to hot extrusion after the fracture of the corresponding samples induced by compression tests was thoroughly investigated. It was found that compression had a dramatic influence on a shear deformation and hence shear fracture of the compressed samples. It was shown that the shear fracture of the hot deformed ductile iron is accompanied by the occurrence of a narrow zone of severe plastic deformation. The fracture surfaces of the extruded samples subjected to the tensile tests and the compression tests were examined.

4

Analysis of the Properties of EN AC 51200 Aluminum Alloy

70%

Uhríčik M. , Palček P. , Chalupová M. , Hanusová P. , Kuchariková L.

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tom Vol. 65, iss. 4

1437--1445

EN

The article will be focused on analysis of properties of aluminum alloy for the casting of type Al-Mg. As an experimental material was used aluminum alloy EN AC 51200, supplied in a cast state without a heat treatment. It was produced by the continuous casting method. Experiments deal with microstructural material analysis, fractographic analysis, mechanical and fatigue tests. The microstructure of the testing sample was examined using an optical microscope Neophot 32. Fatigue properties of aluminum alloy was tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where sample was observed on various stages of the fatigue process, its characteristics and differences of fracture surfaces.

5

The Influence of the Structure on the Fatigue Properties of Al-Mg Cast Alloy

70%

Uhríčik M. , Palček P. , Chalupová M. , Oravcová M. , Frkáň M.

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2017

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tom Vol. 62, iss. 3

1615--1624

EN

The article will be focused on monitoring the influence of the structure on the fatigue properties of aluminium alloys for the casting of type Al-Mg. As an experimental material were used aluminium alloys EN AC 51200 and EN AC 51500, supplied in a cast state without a heat treatment. They were produced by the continuous casting method. These alloys were selected on the basis of the chemical composition, where the content of most alloying elements is comparable, only in the case of the concentration of magnesium are these alloys significantly different. Fatigue properties of aluminium alloys were tested by three-point bending cyclic loading. The fracture surface of the testing sample was examined using scanning electron microscopy (SEM), where samples were observed on various stages of the fatigue process, their characteristics and differences of fracture surfaces.

6

Analysis of the Properties of EN AC 51200 Aluminum Alloy

60%

Uhríčik M. , Palček P. , Chalupová M. , Hanusová P. , Kuchariková L. , Uhríčik M. , Palček P. , Chalupová M. , Hanusová P. , Kuchariková L.

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nr 4

7

Opis powierzchni przełamów wybranych skał metodami morfologii matematycznej

51%

Młynarczuk M. , Ratajczak T. , Aksamit J.

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tom Vol. 6, no. 1-2

79--92

PL

W publikacji przedstawiono wyniki prac mających na celu zbadanie możliwości wykorzystania metod analizy obrazu i morfologii matematycznej do opisu ukształtowania powierzchni przełamów skalnych. Prace te były rozwojem metodyki zaproponowanej w latach 2001-2002 i doprowadziły do częściowej jej modyfikacji oraz uzupełniły ją o nowe parametry. Badania prowadzono na 25 rodzajach przełamów skalnych. W szczególności zbadano zależność zaproponowanych parametrów od: − rodzaju skał różniących się zdecydowanie cechami strukturalno-teksturalnymi (dolomit z Rędzin, piaskowiec z Tumlina, kwarcyt z Wiśniówki, wapień z Czatkowic oraz dolomit z Laskowej Góry), − różnic strukturalno-teksturalnych w ramach skał tego samego typu (12 próbek dolomitów z poziomu wapienia cechsztyńskiego z obszaru kopalni rud miedzi), − sposobu wymuszania przełamów (drobnoziarniste granity ze Strzelina podgrzewane do temperatur 100°, 300° i 500° zostały poddane jednoosiowemu i trójosiowemu ściskaniu). Prowadzone badania wykazały przydatność zaproponowanej metodyki badawczej oraz pozwoliły postawić tezę, że metodyka ta może odpowiedzieć na pytanie czy badana próbka skalna ma podobne cechy strukturalnoteksturalne jak próbka wzorcowa.

EN

The paper presents results of works which aim was to verify a possibility of use the image analysis and mathematical morphology to describing a rock fracture surface. Presented works are continuation of researches started in 2001-2002. The researches were carrying out on 25 different rock samples. In particular the following features were analyzed: – correlation between morphological parameters describing a surface and structural and textural properties of different kinds rock (dolomite from Redzin, sandstone from Tumlin, quartzite from Wisniowka, limestone from Czatkowice and dolomite from Laskowa Gora), – correlation between morphological parameters describing a surface and small structural and textural variation of one rock (12 samples of dolomite from Lubin), – correlation between morphological parameters describing a surface and methodology of brittle crack obtaining (granites from Strzelin heated up to the 100º, 300º and 500ºC, were subject of uiaxial and triaxial loading tests). The researches prove a usefulness of proposed methodology, and lead to the thesis that by means of proposed method it is possible to compare structural and textural properties of analyzed and model rock samples.

8

Mechanical and morphological properties of basalt filled polymer matrix composites

51%

Akinci A.

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tom Vol. 35, nr 1

29-32

EN

Purpose: The aim of this work is to study the effect of basalt on physical, mechanical and morphological of the injection molded LDPE. Design/methodology/approach: In this study, the effect of basalt was investigated as a filler material in polymer matrix composite (PMC) and low density polyethylene (LDPE) was chosen as a matrix material. Findings: A variety of mechanical tests were performed on the resultant composites which has appropriate compositions. Tensile, flexural, density and hardness tests have been carried out and, the relationship between the basalt content and properties were examined. XRD and SEM facilities were applied on polished and fractured surfaces after flexural tests respectively. Research limitations/implications: In present study, it was found that, the content of basalt filler affected structural integrity and mechanical properties of composites. With increasing the amount of the basalt addition to the LDPE results in a decrease in elongation at break values. Originality/value: It is thought that the nucleating effect of the basalt leads to an increased rate in orientation of the polymer. The crystallization was increased by increasing the basalt content. Basalt addition was observed to be an alternative additive to the LDPE. If suitable coupling agents could be added to basalt and LDPE mixtures, the mechanical properties can possibly be increased.