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1
Content available remote

Reliability of the High Strength Pipeline Steel under Corrosion Defect

100%
Ghelloudj O., Zelmati D., Gharbi A., Berdjane D., Ramoul C., Chouchane T.
Acta Physica Polonica A
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2017
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vol. 131
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issue 3
420-422
EN
The demand of energy based on hydrocarbons, such as gas and oil, requires construction of more and more new pipelines. Therefore, the assessment of the remaining life of these pipeline structures became increasingly important to ensure the continuity of production and distribution operations. The reliability of these industrial facilities is largely conditioned by specific characteristics of each system, by its conditions of use and its environment. Generally, the causes of deterioration of hydrocarbon transportation pipelines are related to the presence of apparent defects (pinholes, cracks, corrosion, etc). This study is aimed to estimate the reliability of pipeline structures. The B31G mechanical model of degradation was used to assess the probability of failure through dimensions of defects.
2
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Failure Analysis of a Lower Wishbone

100%
Rutci A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-75-B-77
EN
It is known that wishbone is a hinged suspension link between the chassis and the suspension hub that carries the wheel. This paper describes the failure analysis of a lower wishbone (control arm) in a light commercial vehicle which had been involved in service loading. The wishbone was analyzed in two ways. In order to investigate reason of the failure, finite element modelling was conducted to evaluate stress distribution and reliability of wishbone. Moreover, the metallographic and hardness evaluation were made on weld seam of the failed part. From metallographic observations, the presence of porosity was found in weld seam. Hardness distributions from the parent material to weld region are measured in the expected range. The results of finite element analysis and metallographic examination showed that the fatigue failure was initiated from highly stressed region in weld seam, and the presence of porosity stimulated crack initiation as well as crack growth.
3
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Propagation of Long Fatigue Cracks under Remote Modes II and III in Ferritic-Pearlitic Steel

63%
Vojtek T., Pokluda J., Hohenwarter A., Pippan R.
Acta Physica Polonica A
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2015
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vol. 128
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issue 4
611-614
EN
The aim of this research was to determine the 3D crack path and the related growth micromechanism in specimens made of the ferritic-pearlitic steel loaded in modes II and III. Crack closure effects were minimized at the beginning of the experiments by a special technique of generation of precracks in order to measure effective values of fatigue thresholds. Dependences of the crack growth rate on the stress intensity factor range were plotted for the near-threshold region. The effective mode III threshold ΔK_{IIIeff,th}=4.4 MPam^{1/2} was found to be higher than that for mode II (ΔK_{IIeff,th}=2.9 MPam^{1/2}, the theory predicts 3.1 MPam^{1/2}) which is in agreement with the results for other metallic materials and available theoretical models. Fractographical observations in three dimensions revealed that the remote mode II cracks deflected towards the opening mode I by the mean angle ≈50°, which is significantly different from the low-angle deflections (coplanar growth) previously observed in the ARMCO iron. The simple linear elastic fracture mechanics based criterion for growth of a mode I branch at the crack front loaded in mode II was fulfilled.
4
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Properties and Performance of Tricalcium Silicate Milled in a Planetary Ball Mill

63%
Reformat M., Ludwig H.
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vol. 126
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issue 4
1012-1013
EN
The focus in this study is on the effect of high energy milling on tricalcium silicate, the main constituent of ordinary Portland cement. Changes in the performance, e.g. hydration heat release, due to milling in a planetary ball mill (Pulverisette 5, Fritsch, Germany) were observed. For comparison, carefully milled tricalcium silicate was produced with the almost exactly same particle size distribution by mortar grinding (KM100, Retsch, Germany). In summary, the results indicate that due to high energy milling the performance of tricalcium silicate can be improved significantly: the hydration heat release is much higher at early hydration time. Also the peak and duration of the dormant period was shifted due to high energy milling. The X-ray diffraction analysis shows that the structure of the material changed in such a way that the amorphous content increases. Further results of surface analysis are shown in this study.
5
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Corrosion Influence on the Magnetic Structure of Fe-Based Nanocrystalline Alloys

63%
Sitek J., Sedlackova K., Pavlovic M.
Acta Physica Polonica A
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2008
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vol. 113
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issue 1
613-616
EN
Nanocrystalline alloy of FINEMET and NANOPERM-type were studied by the Mössbauer spectroscopy after atmospheric corrosion up to 10 months. Corrosion process has an influence on the magnetic microstructure, which reflects at the Mössbauer parameters as a change in direction of net magnetic moment, intensity, and distribution of internal magnetic field. During corrosion process the most occurring tendency was the rotation of net magnetic moment out of the ribbon plane. This behaviour might result from the internal stress produced during corrosion treatment. The observed changes in the average hyperfine field and shape of its distribution indicated the changes of the microscopic magnetic properties induced by corrosion damage. These results are compared with radiation corrosion.
6
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Physical-Chemical Analysis of Miter Glass Element Decoration

63%
Greiner-Wronowa E., Kalfas B.
Acta Physica Polonica A
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2012
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vol. 122
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issue 4
781-787
EN
This paper refers to the glass elements, belonging to the XIIIth c. miter, called Saint Stanisław from the Wawel Cathedral Museum in Kraków. The miter so-called Saint Stanisław, has been one of small number preserve miters preserved in Europe, and only one Romanesque style bishop miter in Poland. According to decoration composition is very close to the miter of Calvo bishop (1180-1243) from Diocese Museum in Vic. There were decorative motives, created by embroidering by blue glass beads, and surrounding them by gold thread. The exposition conditions have had fundamental meaning on the miter stage. The glass elements from St. Stanisław's miter were analyzed to solve problem of the place of the miter exposition. It was realized by estimation of glass corrosion category. Moreover, obtained data could help to confirm the hypothesis of displaying it on the altar, which was expected by the historians to their historical documentation. That kind of the XIIIth c. material analyses have never been done before.
7
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Hot Compression Test of Heat Resistant Steel

51%
Fedoriková A., Kvačkaj T., Kočiško R., Bidulský R., Petroušek P.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1340-1343
EN
This article deals with the analysis of formability of heat resistant steel type 9Cr-1Mo by physical laboratory simulation - hot compression test. The 9Cr-1Mo steel belongs to modern 9%Cr tempered martensitic steel for high-temperature applications in advanced thermal power plants. The shape of the sample was defined based on numerical simulations. The laboratory simulation of forming process called physical simulation - specifically hot compression test was realized in the temperature range from 500 to 950°C and total deformation in the range from 39 to 52%. Cracks formed during hot compression test in the notches are assessed. Subsequently, the relation between the compression temperature, strain, and crack length was defined. The suitable workability corresponds to the temperature range 650-900°C, it agrees with results of numerical simulations. At a temperature of 900°C there is marginal relative deformation without rupture ε =39.9%, which corresponds to the value according to simulations NCL criteria 0.501.
8
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A Research on Nitinol Alloy Material Fatigue Behavior Analysis of Cardiovascular Stent in Medical Engineering

51%
Karaçalı Ö.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1167-1169
EN
Biocompatible cardiovascular stents are small cylindrical support structures introduced into the stenosed arteries to reopen the lumen and to restore blood flow in treating heart disease, which have revolutionized interventional cardiology. Cardiovascular stent designers are confronted with two basic requirements, such as an "infinite" life and the "thinnest" wires. Pulsatile pressure, repetitive mechanical forces, within the coronary artery may result in stent fatigue and fracture after stent implantation, particularly in patients with complex coronary disease. This research describes the simulation analysis of cardiovascular stents, to provide designers with estimates of their in vivo structural behavior and fatigue properties. Stent material failure or device fatigue remains major concern for stent manufactures and researchers. The objective of this research was to simulate the mechanical behavior of the stent using finite element method. A finite element analysis (FEA) of cardiovascular stent under fatigue cyclic loading conditions is presented. Commercial software was employed to study the fatigue performance of nitinol alloy materials in new stent systems. The effects of deployment, and static cyclic pressure loading on cardiovascular stent fatigue life were simulated and analyzed for nitinol alloy material. The investigation results displayed a significant correlation between material combinations, stent loading, and fatigue behavior.
9
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Influence of Borosilicate Addition on Mechanical Properties and Sinterability of 8YSZ

51%
Aktas B.
Acta Physica Polonica A
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2016
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vol. 129
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issue 4
677-679
EN
The influence of borosilicate (BS) addition on the mechanical properties and sinterability of yttria-stabilized zirconia (8YSZ) was investigated using scanning electron microscopy (SEM) and Vickers-hardness test. Undoped and 0.5-10 wt.% BS-doped 8YSZ powders were prepared using a colloidal process. The powders were then pelletized under a pressure of 200 MPa. The BS-doped 8YSZ specimens were sintered at 1200-1400°C for 1 h. SEM results showed that intergranular glass phases were formed at the grain boundaries of 8YSZ, particularly in the 5 and 10 wt.% BS-doped 8YSZ specimens. These intergranular glass phases caused a decrease in grain size of 8YSZ. The grain sizes of the undoped and 0.5 wt% BS-doped 8YSZ specimens were 2.68 μm and 1.83 μm, respectively. The addition of BS to 8YSZ caused a decrease in the relative density. In addition, the relative density was found to be increased with higher sintering temperature. The hardness of 8YSZ decreased with the increase in BS dopant amount, due to presence at the grain boundaries of a BS glassy phase that has a lower hardness than 8YSZ.
10
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Analysis of the Fracture Surfaces of New Development Insulated Iron Powder Compounds

51%
Bidulský R., Bidulská J., Kvačkaj T., Actis Grande M.
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vol. 126
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issue 1
154-155
EN
Goal of the present paper is the analysis of the fracture surfaces of an Insulated Iron Powder Compound (IIPC) with different additions of aluminium alloy (0.25, 0.5 and 0.75 wt.%), in order to improve the mechanical properties, evaluated as the transverse rupture strength (TRS) with sufficient magnetic properties (mainly represented by the iron loss and coercivity force). Investigation of microstructure and porosity development concluded that improvements in bending strength and impact values require the reduction of surface oxides during the heat treatment, in order to get a proper load bearing area between the adjacent particles.
11
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Content available

Calculation of Positron Response from Embedded Nanoparticles

51%
Kuriplach J.
Acta Physica Polonica A
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2005
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vol. 107
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issue 5
784-791
EN
Nanoparticles embedded in a matrix can trap positrons under certain conditions. In such cases nanoparticles can be effectively studied by means of positron annihilation because positron annihilation characteristics contain information related to nanoparticles' electronic and atomic structure. Of great importance is to calculate the positron response from such nanoparticles. Then, nanoparticles can, in principle, be identified by comparing the measured and calculated positron annihilation response. For this purpose we present an efficient computational method based on the well-known atomic superposition technique. This method is explained in detail, justified on the basis of first principles calculations, and applied to Cu nanoparticles embedded in the Fe matrix.
12
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Porosity Behaviour of Insulated Iron Powder Compounds

51%
Bidulská J., Bidulský R., Petroušek P., Fedoriková A., Katreničová I., Pokorný I.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1384-1386
EN
The goal of the present paper is to determine the porosity behavior of new development insulated iron powder compounds without and with different additions of aluminum alloy Alumix 321 (5 and 10 wt%). A significant disadvantage of PM processing is the presence of porosity. Pores act as crack initiators and, due to their presence, the distribution of stress is inhomogeneous across the cross-section and leads to the reduction of the effective load bearing area. Quantitative image analysis of investigated material treats pores as isolated plane two-dimensional objects in solid surroundings. To describe the dimensional and morphological porosity characteristics, the dimensional characteristic D_{circle} and the morphological characteristics f_{shape} and f_{circle} were explored. Both the morphology and the distribution of pores shows a significant effect on the cold welding or appropriate bonds between adjacent particles.
13
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Interparticle Neck Connections in Innovative Insulated Iron Powder Compounds

51%
Bidulský R., Bidulská J., de Oro R., Hryha E., Maccarini M., Forno I., Actis Grande M.
Acta Physica Polonica A
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2015
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vol. 128
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issue 4
647-650
EN
Goal of the present paper is the analysis of the interparticle neck connections in a system made of insulated iron powder compounds with different additions of an Al-Mg-Si-Cu alloy (0.25, 0.5 and 0.75 wt%). The introduction of the aluminium alloy powder has been made in order to improve the mechanical properties, evaluated as the transverse rupture strength, without decreasing the magnetic properties (evaluated in terms of iron loss and coercivity force). The fracture analysis of investigated systems puts into evidence the breaking of interparticle neck connections. Heat treatment (at the temperature of 500°C) contributes to the early stages of interparticle neck developments. The chosen aluminium alloy presents a sort of pre-sintering behaviour at 500°C, with the possibility of mass-transport processes around the insulated iron powder compounds. The air heat treatment applied aims at providing an increase in the mechanical behaviour of the material, with a final good rigidity after the cooling process. Fracture surfaces and transverse rupture strength values show that, at 500 MPa, the strength and the area related to the inter-particle necks can be correlated to the occasional broken insulated point-to-point surfaces that hinder the development of inter-particles necks.
14
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Effect of Co₃O₄ on the Fracture Toughness and Microstructure of Yttria-Stabilized Cubic Zirconia (8YSZ)

51%
Aktas B., Tekeli S.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1384-1387
EN
The effects of the addition of Co₃O₄ to yttria-stabilized zirconia (8YSZ) on fracture toughness and microstructure was investigated using micro-indentation and scanning electron microscopy (SEM). Undoped and 1-15 wt.% Co₃O₄-doped 8YSZ powders were prepared using a colloidal process and then pelletized under a pressure of 200 MPa. The 8YSZ specimens were sintered at 1400°C for 1 h. SEM results showed that Co₃O₄ precipitated as a secondary phase among the primary 8YSZ grains. Furthermore, because of the presence of Co₃O₄ secondary phases at the grain boundaries of 8YSZ, the grain sizes of the 8YSZ samples increased with the addition of 1-15 wt.% Co₃O₄. The fracture toughness values of the undoped and 1 wt.% Co₃O₄-doped 8YSZ were determined to be 1.64 and 2.86 MPa m^{1/2}, respectively, indicating the fracture toughness of 8YSZ increased in 1 wt.% Co₃O₄ addition. The fracture toughness of 8YSZ increased upon the addition of 1 wt.% Co₃O₄.
15
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Microdeformation Processes in Soft Magnetic Compounds

51%
Bidulský R., Bidulská J., Petroušek P., Fedoriková A., Dudrová E., Actis Grande M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1367-1370
EN
Porosity can be defined in different ways. The most frequently used definition is the total porosity, which is the total volume fraction of empty space in the specimen. The presence of pores strongly affects the fracture mode. Besides the evaluation of geometry and quality of connections, fractographic analysis enables a quantification of the important microstructural characteristics of the plane porosity. This quantity allows to quantify the existing relations between microstructure and properties. The fractographic evaluation of the distribution of microdeformation processes in the volume of experimental material demonstrates the influence of porosity on the concentration of deformation flows into the microvolume of connections. Plain porosity contributes to the recognition of critical microstructural defects and therefore, to enable evaluating the relationship between the processing parameters, microstructural constituents, and pores. In the fractography evaluation, the analysis of the quality of interparticle bonding using determination of elementary types of fracture facets allows to interpret the mechanical and plastic properties of investigated materials.
16
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Fatigue Test with Stochastic Differential Equation Modeling

51%
Eroglu E., Guney I., Gunes I.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1
36-38
EN
In this study, a mathematically polymeric insulator material is modeled which is used as a solid insulator in the industry. ASTM D 2303 in inclined plane test method is utilized in order to observe mechanical effect of vibration. The materials have different deformation times before they are fatigued or not fatigued. Our goal is the mathematical model which has materials at progressive times.
17
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Evaluation of Fracture Toughness of Thermal Sprayed and Hard Chrome Coated Aluminium-Zinc Alloy

51%
Altuncu E., İriç S.
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EN
The determination of fracture toughness of aluminium alloy aviation parts, exposed to cyclic mechanical loading, is an important engineering issue. The service life and crack resistance of such unprotected metallic parts is limited under corrosive operating conditions. The resistance against fracture cracking and corrosion resistance can be increased by the surface coatings. The scientific research of fracture toughness of coated metallic parts is being carried out in a comprehensive way. In this research, fracture toughness behaviour of high velocity oxy-fuel (HVOF) spray coated and conventional hard chrome plated aluminium-zinc alloy parts were compared and the results are discussed. The fracture surfaces are investigated and fracture toughness values are calculated. Electron microscopy analysis revealed significant differences in crack growth morphology and toughness values. As a result, the fracture toughness value is higher in hard chrome plated parts.
18
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Fatigue Analysis of Ti-55 Alloy Material for Multifunctional Surgical Instruments in Medical Engineering

51%
Karaçalı Ö.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1199-1201
EN
A new approach is proposed for fatigue prediction in medical engineering of multifunctional microforceps-scissors (MFS), transconjunctival sutureless vitroretinal metal surgical instrument that removes, grasp, chops tissues and inserts new in a cell. Cyclic loads can result in the fatigue failure of MFS at stress levels below the yielding stress of material. Hence, research of the material and mechanical behavior of a MFS structure under a cyclic load is required. The numerical modeling of a cyclic load fatigue test was performed for a biocompatible MFS, by using finite element analysis (FEA). To verify the data gathered from von Mises' yield condition, Haigh diagram was developed to predict fatigue life. Fatigue behavior of the MFS was analyzed in ANSYS LS-DYNA under operation load conditions in vitrectomy. This research analyzes the application of forces to the examined MFS, resulting in different movements, which cause fatigue during surgery. The numerical analysis consisted in solving the strains and stresses distribution in the operating part of the MFS, made of Ti-55 alloy (Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd) medical material. The maximum values of strain and stress were calculated for the Ti-55 alloy, using values of elasticity modulus of 119 GPa, and Poisson's ratio of 0.32. The outcomes of the fatigue analysis from this research will be beneficial for micro component manufacturers in medical engineering and for clinic surgeons.
19
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Material Fatigue Research for Zirconia Ceramic Dental Implant: a Comparative Laboratory and Simulation Study in Dentistry

51%
Karaçalı Ö.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1195-1198
EN
This research focuses on the biocompatible zirconia ceramic (ZrO₂) material and load behavior causing fatigue on the surface of the dental implant in dentistry. Fatigue fracture and wear have been identified as some of the major problems associated with implant loosening, stress-shielding and ultimate implant failure. A static and cyclic fatigue testing of ceramic dental implant in laboratory conditions for this investigation were carried out according to the ISO protocol 14801 under worst-case conditions. A finite element analysis (FEA) of dental implant with accurate geometry and material properties were developed to make realistic investigations on biocompatibility of the implant biomaterial properties and mechanical fatigue behavior of new dental implant comparing Von-Mises criteria and maximum stress levels. The comparison of calculated fatigue life simulation data of and experimental data for the biocompatible zirconia ceramic dental implants is presented. As a conclusion zirconium implant exceeded the established values for maximum incisal bite forces reported in the literature and and also shows better performance than titanium implant material. The results of fatigue of biocompatible zirconia analysis are helpful for implant biomaterial selection and design for clinical interest in dentistry.
20
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Investigation of Fracture Surfaces of Soft Magnetic Materials

51%
Bidulská J., Kvačkaj T., Bidulský R., Actis Grande M., Ferraris L.
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issue 5
800-801
EN
The present paper focused on the analysis of the fracture surfaces of a new development insulated iron powder compound with the addition of the aluminium alloy in order to improve the mechanical properties. Results show that in the pressed state, mainly pores act as crack initiators and due to their presence the distribution of stress is inhomogeneous across the cross-section and leads to the reduction of the effective load bearing area. Investigation of fracture surfaces concluded that improvements in bonding during the pressing process and heat treatment can be helpful in the development of soft magnetic materials to give a suitable combination between pressing pressure, annealing temperature and time as well as magnetic properties.
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