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Analysis of magnetic field effect on ferromagnetic spheres embedded in elastomer pattern.
(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2010) Boczkowska, Anna; Czechowski, Leszek; Jaroniek, Mieczysław; Niezgoda, Tadeusz
The results of modelling of the magnetorheological elastomers (MREs) microstructure using Finite Elements Method (FEM) are shown. MREs are solids analogous to magnetorheological fluids consisting of carbonyl-iron particles and a soft elastomer matrix. Fabrication of MREs is performed in an external constant magnetic field. Due to the presence of this field, the ferromagnetic particles tend to arrange themselves into elongated chains according to the magnetic field lines. FEM analysis of the MREs microstructure takes into account two cases: magnetic power and elastic vectors as well as their interactions between the components of the composite. The paper describes spatial ordering of the particles based on their interactions with the magnetic field. Two phenomena were taken into account: the force of a magnetic field and the local magnetic dipoles. Both fields have been modelled for a circular conductor with electrical current.
Application of Photoelasticy for Study of Lamellar Cracks.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2013) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
In rolled sheets, non–metallic inclusions are distributed along the thickness of the sheet as narrow lines running parallel to the rolling direction. Such inclusions are the nuclei of lamellar cracks. This work presents the application of the photoelastic method for study of lamellar cracking. Photoelastic models of samples with long artificial fissures set in the area of the sheet axis were studied along with other encountered inclusion distributions. The studied samples were placed in a polariscope and subjected to uniform tension; isochromatic images were obtained. Changes in the stress state in the area of the inclusion were observed as the load increased. Stress concentration leads to the formation of lamellar cracks – the joining of voids in the direction parallel to the exterior surface of the sheet (so–called ”terraces” are formed) and at angles (so–called ”jogs” are formed). The results of photoelastic tests were compared with the results of numerical calculations using the finite element method.
Element Birth and Death Method Application to Lamellar Crack Analysis
(Wydawnictwo Politechniki Łódzkiej ; Katedra Dynamiki Maszyn - Wydział Mechaniczny Politechniki Łódzkiej, 2015) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
Load structure, the maximum permissible load is usually determined by the strength calculation (bearing data. Yield stress or strength of the material), or the parameters of fracture mechanics. The paper analyzes the calculations lamellar cracks formed in the lower crane girders steel belts. These cracks are formed in rolled sheets of non-metallic inclusions. The determination of the cracks in the existing designs are extremely difficult. It requires testing metallographic, ultrasonic or acoustic methods. Based on typical images of metallographic steel plates specified place of occurrence of cracks lamellar and sampling, and has subsequently been adopted for the calculation of numerical models of material structure and distribution of artificial joints. In order to analyze the propagation of cracks and formation of lamellar phase slots and destruction was carried out modeling studies and numerical methods cracking process.
Element Birth and Death Method Application to Lamellar Crack Analysis.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2015) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
Load structure, the maximum permissible load is usually determined by the strength calculation (bearing data. Yield stress or strength of the material), or the parameters of fracture mechanics. The paper analyzes the calculations lamellar cracks formed in the lower crane girders steel belts. These cracks are formed in rolled sheets of non–metallic inclusions. The determination of the cracks in the existing designs are extremely difficult. It requires testing metallographic, ultrasonic or acoustic methods. Based on typical images of metallographic steel plates specified place of occurrence of cracks lamellar and sampling, and has subsequently been adopted for the calculation of numerical models of material structure and distribution of artificial joints. In order to analyze the propagation of cracks and formation of lamellar phase slots and destruction was carried out modeling studies and numerical methods cracking process.
Experimental model of fracture of functionally graded materials.
(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2010) Jaroniek, Mieczysław
Fabrication of functionally graded materials (FGM) can be obtained by layeredmixing of two materials of different thermo-mechanical properties with different volume ratios gradually changing from layer to layer such that the first layer has only a few particles of the second phase and the last has the maximum volume ratio of the first phase. Consider a simple model of the functionally graded materials as a multilayered beam bonded to planes having shear modulus G_i and Poisson's ratio [ni]_I, respectively, subjected to bending. The behaviour of cracks depends on cracks configuration, size, orientation, material properties, and loading characteristic. The fracture mechanics problem will be approached by making use of photoelastic visualisation of fracture events in the model structure.
Fatigue of Steel Plates with Inclusions
(Wydawnictwo Politechniki Łódzkiej ; Katedra Dynamiki Maszyn - Wydział Mechaniczny Politechniki Łódzkiej, 2015) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
Manufactured by the end of the 80s in the last century steel structures were made of steel which contain significant amounts of non-metallic inclusions. As a result of many years of intensive use of the structures made of steel, structural discontinuity material combine to form internal cracks called lamellar cracks. These cracks are formed in rolled sheets with non-metallic inclusions. Studies of lamellar cracks began in the 1960s, but there is still no satisfactory theory explaining their formation.
Fatigue of Steel Plates with Inclusions
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2015) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
Manufactured by the end of the 80s in the last century steel structures were made of steel which contain signi cant amounts of non-metallic inclusions. As a result of many years of intensive use of the structures made of steel, structural discontinuity material combine to form internal cracks called lamellar cracks. These cracks are formed in rolled sheets with non-metallic inclusions. Studies of lamellar cracks began in the 1960s, but there is still no satisfactory theory explaining their formation.
Mathematical and Experimental Analysis Tension of Steel in Bi-Polar Coordinates.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2016) Jaroniek, Mieczysław
A series of experiments was carried out to examine the effects of elastic–plastic deformation on the state of stress and the flow stress mechanism under static tension. The strain distribution determined from the fringe pattern using the Moire method allows one to determine the strain and the crack propagation of not–notched specimens an isotropic and elastic–plastic materials. In the analysis of stress the method of calculating using the bipolar coordinate is proposed. The theoretical model is divided into two elements and the condition of incompressibility is satisfied in each element. The proposed method is compared with the elastic-plastic FEM (ANSYS 12, 14) and it is satisfied approximately. The tensile test is aimed to verify the mathematical model that can be applied in the logarithmic stain in further computations.
Modeling Lamellar Cracks.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2013) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
In this work, studies of models simulating lamellar cracks were conducted. These cracks are formed in rolled sheets with non-metallic inclusions. Studies of lamellar cracks began in the 1960s, but there is still no satisfactory theory explaining their formation. In this work, the application of modeling of samples with non-metallic inclusions for the study of lamellar cracking has been presented. Studies were conducted using two research methods: the photoelastic method and the finite element method. The possibility of crack formation was analyzed in models generated from images obtained from metallographic specimens.
Podstawy mechaniki technicznej : dla studentów wydziału elektrotechniki i elektroniki
(Wydawnictwo Politechniki Łódzkiej, 2004) Jaroniek, Mieczysław; Red. nauk. Wydz. : Ostalczyk, Piotr; Królak, Marian
Książka ma na celu ułatwienie opanowania podstaw mechaniki ogólnej oraz wytrzymałości materiałów. W innych podręcznikach, zwłaszcza przeznaczonych dla studentów wydziałów mechanicznych i budowlanych, (podanych w literaturze) zakres materiału jest znacznie szerszy, natomiast w niniejszym skrypcie przedstawiono w zarysie jedynie podstawowe metody obliczeń. Celem skryptu jest przedstawienie w możliwie skróconej formie podstawowych wiadomości z mechaniki teoretycznej i wytrzymałości materiałów z uwzględnieniem zastosowania podanych elementów teorii do badań i obliczeń współczesnych konstrukcji.
Propagation of the Lamellar Cracks.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2014) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
The aim of the study is to include studying the effects of the interaction of lamellar cracks and their effect on the degradation of the structure. Lamellar cracking phenomenon is most common in the construction of welded ship hulls, bridges, pressure vessels and piping. The structures of these, as a result of errors in production and welding cracks. The sudden breakage occurs in the construction of real time, although they have been designed properly in terms of both the volume of the stress and strain. The growth of these cracks, at a rate equal to the speed of sound in the material, it is a sudden breakage.
Stan naprężenia w elastomerze zawierającym cząstki ferromagnetyczne w polu magnetycznym.
(Stowarzyszenie Inżynierów i Techników Mechaników Polskich, 2010) Boczkowska, Anna; Czechowski, Leszek; Jaroniek, Mieczysław; Niezgoda, Tadeusz
Przedstawiono wyniki analizy modelowania metodą elementów skończonych oraz badań metodą elastooptyki magnetoreologicznego elastomeru w obecności pola magnetycznego. Celem przeprowadzonych symulacji numerycznych i badań eksperymentalnych było uzyskanie wiedzy o wzajemnym oddziaływaniu elastomeru i kulek żelaza (wyznaczenie wartości odkształcenia i naprężenia) oraz zdobycie doświadczenia niezbędnego do modelowania takich oddziaływań na poziomie mikrostruktury w rzeczywistym elastomerze zawierającym cząstki żelaza o wymiarach mikronowych.
Study of the Formation of Lamellar Cracks.
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2014) Jaroniek, Mieczysław; Niezgodziński, Tadeusz
In rolled sheets, non-metallic inclusions are distributed along the thickness of the sheet as narrow lines running parallel to the rolling direction. Such inclusions are the nuclei of lamellar cracks. This work presents the application of the numerical method for study of lamellar cracking. Numerical models of samples with long artificial fissures set in the area of the sheet axis were studied along with other encountered inclusion distributions. Changes in the stress state in the area of the inclusion were observed as the load increased. Stress concentration leads to the formation of lamellar cracks - the joining of voids in the direction parallel to the exterior surface of the sheet (so-called "terraces" are formed) and at angles (so-called "jogs" are formed). The results of experimental tests were compared with the results of numerical calculations using the finite element method.