Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 23
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The paper deals with the problem of force and torque calculation for linear, cylindrical and spherical electromechanical converter.

The electromagnetic field is determined analytically with the help of separation method for each problem. The results obtained can be used as test tasks for electromagnetic field, force and torque numerical calculations. The analytical relations for torque and forces are also convenient for analysis of material parameters influence on electromechanical converter work.

Go to article

Authors and Affiliations

D. Spałek
Download PDF Download RIS Download Bibtex

Abstract

An extension of the modified Jiles-Atherton description to include the effect of anisotropy is presented. Anisotropy is related to the value of the angular momentum quantum number J, which affects the form of the Brillouin function used to describe the anhysteretic magnetization. Moreover the shape of magnetization dependent R(m) function is influenced by the choice of the J value.
Go to article

Authors and Affiliations

Krzysztof Chwastek
Jan Szczygłowski
Download PDF Download RIS Download Bibtex

Abstract

While analyzing shape accuracy of ferroalloy precision castings in terms of ceramic moulds physical anisotropy, low-alloy steel castings

("cover") and cast iron ("plate") were included. The basic parameters in addition to the product linear shape accuracy are flatness

deviations, especially due to the expanded flat surface which is cast plate. For mentioned castings surface micro-geometry analysis was

also carried, favoring surface load capacity tp50 for Rmax = 50%.

Surface load capacity tp50 obtained for the cast cover was compared with machined product, and casting plate surface was compared with

wear part of the conveyor belt. The results were referred to anisotropy of ceramic moulds physical properties, which was evaluated by

studying ceramic moulds samples in computer tomography equipment Metrotom 800.

Go to article

Authors and Affiliations

R. Biernacki
R. Haratym
J. Tomasik
J. Kwapisz
Download PDF Download RIS Download Bibtex

Abstract

The study attempts to investigate the influence of severe plastic deformation (SPD in the hydrostatic extrusion (HE) process on the anisotropy of the structure and mechanical properties of the AA 6060 alloy. Material in isotropic condition was subjected to a single round of hydrostatic extrusion with three different degrees of deformation (ε  = 1.23, 1.57, 2.28). They allowed the grain size to be fragmented to the nanocrystalline level. Mechanical properties of the AA 6060 alloy, examined on mini-samples, showed an increase in ultimate tensile strength (UTS) and yield strength (YS) as compared to the initial material. Significant strengthening of the material results from high grain refinement in transverse section, from »220 μm in the initial material to »300 nm following the HE process. The material was characterized by the occurrence of structure anisotropy, which may determine the potential use of the material. Static tensile tests of mini-samples showed »10% anisotropy of properties between longitudinal and transverse cross-sections. In the AA6060 alloy, impact anisotropy was found depending on the direction of its testing. Higher impact toughness was observed in the cross-section parallel to the HE direction. The results obtained allow to analyze the characteristic structure created during the HE process and result in more efficient use of the AA 6060 alloy in applications.

Go to article

Authors and Affiliations

S. Przybysz
M. Kulczyk
W. Pachla
J. Skiba
M. Wróblewska
J. Mizera
D. Moszczyńska
Download PDF Download RIS Download Bibtex

Abstract

Anisotropy of variations of Polish mineral deposit parameters is rarely the subject of interest of geologists who carry on the assessment projects . However, if the anisotropy is strong its description and mathematical modeling are rational and justified as it may affect the accuracy of many calculations suitably for mining geology and mining engineering, e.g. estimation of resources and grade of particular raw-material, interpolation of deposit parameters values and construction of their contour maps, designing of optimum grade mining operations or densification of sampling grid. In geostatistics anisotropy is described with directional semivariograms which represent average variability of values of particular deposit parameter in various directions, depending on the distance between sampling sites. Convenient graphic presentation of anisotropy is map of directional semivariograms and good mathematical presentation are functions describing the anisotropy models.

The paper presents the results of geostatistical descriptions of various anisotropy types in selected examples of Polish mineral deposits. Taking into account the spherical variability model, the influence of anisotropy on the results of deposit parameters estimations has been theorized for both the interpolation point and calculation block (area). It was found that anisotropy is effective for parameters estimation if three mutually interrelated factors are considered: power of directional diversification of parameters variation, contribution of random component to total, observed variation of parameters and the range of semivariograms (autocorrelation) of parameter referred to the average sampling grid density.

The results demonstrate that anisotropy influences much more the estimations of parameters value in interpolation points than those of average values of parameters calculated for particular parts of deposit (calculation blocks). Moreover, anisotropy is unimportant when the random component of variability dominates the overall variability of analyzed parameter. Therefore, the simpler, isotropic variability model can be applied to geostatistical estimations of deposit parameters.

Go to article

Authors and Affiliations

Jacek Mucha
ORCID: ORCID
Monika Wasilewska-Błaszczyk
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

For the purpose of making of a solid body of an electric guitar the acoustic- and mechanical properties of walnut- (Juglans regia L.) and ash wood (Fraxinus excelsior L.) were researched. The acoustic properties were determined in a flexural vibration response of laboratory conditioned wood elements of 430 × 186 × 42.8 mm used for making of a solid body of an electric guitar. The velocity of shearand compression ultrasonic waves was additionally determined in parallel small oriented samples of 80 × 40 × 40 mm. The research confirmed better mechanical properties of ash wood, that is, the larger modulus of elasticity and shear modules in all anatomical directions and planes. The acoustic quality of ash wood was better only in the basic vibration mode. Walnut was, on the other hand, lighter and more homogenous and had lower acoustic- and mechanical anisotropy. Additionally, reduced damping of walnut at higher vibration modes is assumed to have a positive impact on the vibration response of future modelled and built solid bodies of electric guitars. When choosing walnut wood, better energy transfer is expected at a similar string playing frequency and a structure resonance of the electric guitar.

Go to article

Authors and Affiliations

Anton Zorič
Jasmin Kaljun
Ervin Žveplan
Aleš Straže
Download PDF Download RIS Download Bibtex

Abstract

Magnetic properties of silicon iron electrical steel are determined by using standardized measurement setups and distinct excitation parameters. Characteristic values for magnetic loss and magnetization are used to select the most appropriate material for its application. This approach is not sufficient, because of the complex material behavior inside electrical machines, which can result in possible discrepancies between estimated and actual machine behavior. The materials’ anisotropy can be one of the problems why simulation and measurement are not in good accordance.With the help of a rotational single sheet tester, the magnetic material can be tested under application relevant field distribution. Thereby, additional effects of hysteresis and anisotropy can be characterized for detailed modelling and simulation.

Go to article

Authors and Affiliations

Gregor Bavendiek
Nora Leuning
ORCID: ORCID
Fabian Müller
Benedikt Schauerte
ORCID: ORCID
Andreas Thul
Kay Hameyer
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

In this study, the effect of the coiling temperature on the tensile properties of API X70 linepipe steel plates is investigated in terms of the microstructure and related anisotropy. Two coiling temperatures are selected to control the microstructure and tensile properties. The API X70 linepipe steels consist mostly of ferritic microstructures such as polygonal ferrite, acicular ferrite, granular bainite, and pearlite irrespective of the coiling temperature. In order to evaluate the anisotropy in the tensile properties, tensile tests in various directions, in this case 0° (rolling direction), 30°, 45° (diagonal direction), 60°, and 90° (transverse direction) are conducted. As the higher coiling temperature, the larger amount of pearlite is formed, resulting in higher strength and better deformability. The steel has higher ductility and lower strength in the rolling direction than in the transverse direction due to the development of γ-fiber, particularly the {111}<112> texture.
Go to article

Authors and Affiliations

Dong-Kyu Oh
1
ORCID: ORCID
Seung-Hyeok Shin
1
ORCID: ORCID
Sang-Min Lee
2
ORCID: ORCID
Byoungchul Hwang
1
ORCID: ORCID

  1. Seoul National University of Science and Technology, Department of Materials Science and Engineering, Seoul, 01811, Republic of Korea
  2. Hyundai Steel Company, Dangjin-Si, Chungnam, 31719, Republic of Korea
Download PDF Download RIS Download Bibtex

Abstract

The Goss texture is a characteristic feature of grain-oriented transformer steel sheets. Generator sheets, which are produced as non-oriented steel sheets, should have isotropic features. However, measurement results of generator sheets, confirmed by crystallographic studies, indicate that these sheets are characterized by certain, quite significant anisotropy. The first purpose of this paper is to present the influence of textures of generator and transformer steel sheets on their magnetization characteristics. The second aim is to propose a method which takes into account the sheet textures in the calculations of magnetization curves. In calculations of magnetization processes in electrical steel sheets, models in which the plane of a sheet sample is divided into an assumed number of specified directions are used. To each direction a certain hysteresis loop, the so-called direction hysteresis, is assigned. The parameters of these direction hystereses depend, among other things, on the texture type in these steel sheets. This paper discusses the method which calculates the parameters of these direction hystereses taking into account the given sheet texture. The proposed method gives a possibility of determining the magnetization characteristics for any direction of the field intensity changes.

Go to article

Authors and Affiliations

Witold Mazgaj
Adam Warzecha
Download PDF Download RIS Download Bibtex

Abstract

An axially symmetric, gravity driven, steady flow of a grounded polar ice sheet with a prescribed temperature field is considered.

The ice is treated as an incompressible, non-linearly viscous, anisotropic fluid, the internal structure (fabric) of which evolves as ice descends from the free surface to depth in an ice sheet. The evolution of the ice fabric is described by an orthotropic constitutive law which relates the deviatoric stress to the strain-rate, strain, and three structure tensors based on the current (rotating) principal stretch axes. The solution of the problem is constructed as a leading-order approximation derived from asymptotic expansions in a small parameter that reflects the small ratio of stress and velocity gradients in the lateral direction of the ice sheet to those in the thickness direction. Numerical simulations of the flow problem have been carried out for various sets of rheological parameters defining the limit strength of the anisotropic fabric in ice. The results of calculations illustrate the influence of the ice anisotropy, basal melt conditions and temperature field in ice on the glacier thickness and lateral span, and on the depth profiles of the flow velocity.

Go to article

Authors and Affiliations

R. Staroszczyk
Download PDF Download RIS Download Bibtex

Abstract

A multi-laminate constitutive model for soft soils incorporating structural anisotropy is presented. Stress induced anisotropy of strength, which is present in multi-laminate type constitutive models, is augmented by directionally distributed overconsolidation. The model is presented in theelastic-plastic version in order to simulate strength anisotropy of soft clayey soils and destructuration effects. Performance of the model is shown for some element tests and for the numericalsimulation of a trial road embankment constructed on soft clays at Haarajoki, Finland. The numerical calculations are completed with the commercial finite element code capable to performcoupled static/consolidation analysis of soils. Problems related to the initiation of in situ stress state, conditions of preconsolidation, as well as difficulties linked to estimation of the model parametersare discussed. Despite simple assumptions concerning field conditions and non-viscous formulationof the constitutive model, the obtained final results are of a sufficient accuracy for geotechnical practice.

Go to article

Authors and Affiliations

M. Cudny
Download PDF Download RIS Download Bibtex

Abstract

The behaviour of energy levels and optical spectra of a charged particle (electron or hole) confined within a potential well of ellipsoidal shape is investigated as a function of the shape-anisotropy parameter. If two energy levels of the same symmetry intersect in a perturbation-theory approximation, they move apart on direct diagonalization of the appropriate Hamiltonian. The intersection of the energy levels leads to a discontinuity of the corresponding dipole-moment matrix element. The discontinuity of matrix elements is not reflected in the behaviour of transition probabilities which are continuous functions of the shape-anisotropy parameter. The profiles of a spectral line emitted or absorbed by an ensemble of ellipsoidally shaped nanoparticles with a Gaussian distribution of size are calculated and discussed.

Go to article

Authors and Affiliations

T. Kereselidze
T. Tchelidze
A. Devdariani
Download PDF Download RIS Download Bibtex

Abstract

We have presented dielectric and conductivity studies of two liquid crystal (LC) compounds- p-octyloxybenzoic acid (8OBA) and p-decyloxybenzoic acid (10OBA). Dielectric permittivity study of those compounds gives the evidence of space charge polarization and ionic conductance in the samples. Dielectric permittivity is found to be the highest for 8OBA than 10OBA. Both compounds found to exhibit positive dielectric anisotropy. Splay elastic constant as a function of temperature has also been investigated. Frequency and temperature dependent electrical conductivity of these two LC compounds have been studied in detail. Activation energy has been estimated from both dc and ac conduction process.

Go to article

Authors and Affiliations

S. Patari
A. Nath
Download PDF Download RIS Download Bibtex

Abstract

In the present investigation optical, electro-optical and dielectric properties have been measured for nematic liquid crystal (NLC) material 1550C which consists of 4’-(trans, trans-4-alkylbicyclohexyl) carbonates and 4’-(4-(trans,trans-4-alkyl)-4-cyanobicyclohexane, dispersed with fluorescent dye (Benzo 2,1,3 Thiadiazole) in two different concentrations. Photoluminescence has been enhanced for a dye dispersed system which is the key finding of this investigation. UV absorbance study has also been performed and found to be increased for composite system. Enhanced birefringence after dispersion of dye into pure NLC is also a prominent result of this investigation. Relative permittivity, threshold voltage and dielectric anisotropy have also been measured and found to be increased. The outcome of the present work may be very useful in the construction of liquid crystal displays (LCDs).

Go to article

Authors and Affiliations

G. Pathak
K. Agrahari
A. Roy
A. Srivastava
O. Strzezysz
K. Garbat
R. Manohar
Download PDF Download RIS Download Bibtex

Abstract

The methods of severe plastic deformation (SPD) of metals and metal alloys are very attractive due to the possibility of refinement of the grains to nanometric sizes, which facilitates obtaining high mechanical properties. This study investigated the influence of SPD in the process of hydrostatic extrusion (HE) on the anisotropy of the mechanical properties of the CuCrZr copper alloy. The method of HE leads to the formation of a characteristic microstructure in deformed materials, which can determine their potential applications. On the longitudinal sections of the extruded bars, a strong morphological texture is observed, manifested by elongated grains in the direction of extrusion. In the transverse direction, these grains are visible as equiaxed. The anisotropy of properties was mainly determined based on the analysis of the static mini-sample static tensile test and the dynamic impact test. The obtained results were correlated with microstructural observations. In the study, three different degrees of deformation were applied at the level necessary to refine the grain size to the ultrafine-grained level. Regardless of the applied degree of deformation, the effect of the formation of a strong morphological texture was demonstrated, as a result of which there is a clear difference between the mechanical properties depending on the test direction, both by the static and dynamic method. The obtained results allow for the identification of the characteristic structure formed during the HE process and the more effective use of the CuCrZr copper alloy in applications.
Go to article

Authors and Affiliations

Sylwia Przybysz
1
Mariusz Kulczyk
1
ORCID: ORCID
Jacek Skiba
1
Monika Skorupska
1

  1. Institute of High Pressure Physics of the Polish Academy of Sciences, Warszawa, Poland
Download PDF Download RIS Download Bibtex

Abstract

The automotive industry requires more and more light materials with good strength and formability at the same time. The answer to this type of demands are, among others, aluminium alloys of the 6xxx series, which are characterized by a high strength-to-weight ratio and good corrosion resistance. Different material state can affect formability of AlMgSi sheets. These study analysed the influence of heat treatment conditions on the drawability of the sheet made of 6082 aluminium alloy. The studies on mechanical properties and plastic anisotropy for three orientations (0, 45, 90°) with respect to the rolling direction were carried out. The highest plasticity was found for the material in the 0 temper condition. The influence of heat treatment conditions on the sheet drawability was analysed using the Erichsen, Engelhardt-Gross, Fukui and AEG cupping tests. It was found that the material state influenced the formability of the sheet. In the case of bulging, the sheet in the annealed state was characterized by greater drawability, and in the deep drawing process, greater formability was found for the naturally aged material.
Go to article

Bibliography

[1] W. Muzykiewicz, Validation tests for the 6082-grade sheet in the "0" state with an account of its application for deep drawing processes. Rudy i Metale Nieżelazne, 51(7):422–427, 2006. (in Polish).
[2] A.C.S. Reddy, S. Rajesham, P.R. Reddy, and A.C. Umamaheswar. Formability: A review on different sheet metal tests for formability. AIP Conference Proceedings, 2269:030026, 2020. doi: 10.1063/5.0019536.
[3] Y. Dewang, V. Sharma, and Y. Batham. influence of punch velocity on deformation behavior in deep drawing of aluminum alloy. Journal of Failure Analysis and Prevention, 21(2):472–487, 2021. doi: 10.1007/s11668-020-01084-5.
[4] S. Bansal. Study of Deep Drawing Process and its Parameters Using Finite Element Analysis. Master Thesis, Delhi Technological University, India, 2022.
[5] E. Nghishiyeleke, M. Mashingaidze, and A. Ogunmokun, Formability characterization of aluminium AA6082-O sheet metal by uniaxial tension and Erichsen cupping tests. International Journal of Engineering and Technology, 7(4):6768–6777, 2018.
[6] J. Adamus, M. Motyka, and K. Kubiak. Investigation of sheet-titanium drawability. In: 12th World Conference on Titanium (Ti-2011), Beijing, China, 19-24 June 2011.
[7] R.R. Goud, K.E. Prasad, and S.K. Singh. formability limit diagrams of extra-deep-drawing steel at elevated temperatures. Procedia Materials Science, 6:123–128, 2014. doi: 10.1016/j.mspro.2014.07.014.
[8] R. Norz, F.R. Valencia, S. Gerke, M. Brünig, and W. Volk. Experiments on forming behaviour of the aluminium alloy AA6016. IOP Conference Series: Materials Science and Engineering, 1238(1):012023, 2022. doi: 10.1088/1757-899X/1238/1/012023.
[9] W.S. Miller, L. Zhuang, J. Bottema, A.J. Wittebrood, P. De Smet, A. Haszler, and A. Vieregge. Recent development in aluminium alloys for the automotive industry. Materials Science and Engineering: A, 280(1):37–49, 2000. doi: 10.1016/S0921-5093(99)00653-X.
[10] J.C. Benedyk. Aluminum alloys for lightweight automotive structures. In P.K. Mallick (ed.): Materials, Design and Manufacturing for Lightweight Vehicles. Woodhead Publishing, pages 79–113, 2010. doi: 10.1533/9781845697822.1.79.
[11] M. Bloeck. Aluminium sheet for automotive applications. In J. Rowe (ed.): Advanced Materials in Automotive Engineering. Woodhead Publishing Limited, pages 85–108, 2012. doi: 10.1533/9780857095466.85.
[12] N.I. Kolobnev, L.B. Ber, L.B. Khokhlatova, and D.K. Ryabov. Structure, properties and application of alloys of the Al – Mg – Si – (Cu) system. Metal Science and Heat Treatment, 53(9-10):440–444, 2012. doi: 10.1007/s11041-012-9412-8.
[13] P. Lackova, M. Bursak, O. Milkovic, M. Vojtko, and L. Dragosek, Influence of heat treatment on properties of EN AW 6082 aluminium alloy. Acta Metallurgica Slovaca, 21(1):25–34, 2015. doi: 10.12776/ams.v21i1.553.
[14] R. Prillhofer, G. Rank, J. Berneder, H. Antrekowitsch, P. Uggowitzer, and S. Pogatscher. Property criteria for automotive Al-Mg-Si sheet alloys. Materials, 7(7):5047–5068, 2014. doi: 10.3390/ma7075047.
[15] N.C.W. Kuijpers, W.H. Kool, P.T.G. Koenis, K.E. Nilsen, I. Todd, and S. van der Zwaag. Assessment of different techniques for quantification of α-Al(FeMn)Si and β-AlFeSi intermetallics in AA 6xxx alloys. Materials Characterization, 49(5):409–420, 2002. doi: 10.1016/S1044-5803(03)00036-6.
[16] G. Mrówka-Nowotnik. Influence of chemical composition variation and heat treatment on microstructure and mechanical properties of 6xxx alloys. Archives of Materials Science and Engineering, 46(2):98–107, 2010.
[17] G. Mrówka-Nowotnik, J. Sieniawski, and A. Nowotnik. Tensile properties and fracture toughness of heat treated 6082 alloy. Journal of Achievements of Materials and Manufacturing Engineering, 12(1-2):105–108, 2006.
[18] G. Mrówka-Nowotnik, J. Sieniawski, and A. Nowotnik. Effect of heat treatment on tensile and fracture toughness properties of 6082 alloy. Journal of Achievements of Materials and Manufacturing Engineering, 32(2):162–170, 2009.
[19] X. He, Q. Pan, H. Li, Z. Huang, S. Liu, K. Li, and X. Li. Effect of artificial aging, delayed aging, and pre-aging on microstructure and properties of 6082 aluminum alloy. Metals, 9(2):173, 2019. doi: 10.3390/met9020173.
[20] Z. Li, L. Chen, J. Tang, G. Zhao, and C. Zhang. Response of mechanical properties and corrosion behavior of Al–Zn–Mg alloy treated by aging and annealing: A comparative study. Journal of Alloys and Compounds, 848:156561, 2020. doi: 10.1016/j.jallcom.2020.156561.
[21] J.R. Hirsch. Automotive trends in aluminium - the European perspective. Materials Forum, 28(1):15–23, 2004.
[22] W. Moćko and Z.L. Kowalewski. Dynamic properties of aluminium alloys used in automotive industry. Journal of KONES Powertrain and Transport, 19(2):345–351, 2012.
[23] N. Kumar, S. Goel, R. Jayaganthan, and H.-G. Brokmeier. Effect of solution treatment on mechanical and corrosion behaviors of 6082-T6 Al alloy. Metallography, Microstructure, and Analysis, 4(5):411–422, 2015. doi: 10.1007/s13632-015-0219-z.
[24] M. Fujda, T. Kvackaj, and K. Nagyová. Improvement of mechanical properties for EN AW 6082 aluminium alloy using equal-channel angular pressing (ECAP) and post-ECAP aging. Journal of Metals, Materials and Minerals, 18(1):81–87, 2008.
[25] I. Torca, A. Aginagalde, J.A. Esnaola, L. Galdos, Z. Azpilgain, and C. Garcia. Tensile behaviour of 6082 aluminium alloy sheet under different conditions of heat treatment, temperature and strain rate. Key Engineering Materials, 423:105–112, 2009. doi: 10.4028/www.scientific.net/KEM.423.105.
[26] O. Çavuşoğlu, H.İ. Sürücü, S. Toros, and M. Alkan, Thickness dependent yielding behavior and formability of AA6082-T6 alloy: experimental observation and modeling. The International Journal of Advanced Manufacturing Technology, 106:4083–4091, 2020. doi: 10.1007/s00170-019-04878-6.
[27] J. Slota, I. Gajdos, T. Jachowicz, M. Siser, and V. Krasinskyi. FEM simulation of deep drawing process of aluminium alloys. Applied Computer Science, 11(4):7–19, 2015.
[28] Ö. Özdilli. An investigation of the effects of a sheet material type and thickness selection on formability in the production of the engine oil pan with the deep drawing method. International Journal of Automotive Science And Technology, 4(4):198–205, 2020. doi: 10.30939/ijastech..773926.
[29] W.T. Lankford, S.C. Snyder, and J.A. Bauscher. New criteria for predicting the press performance of deep drawing sheets. ASM Transactions Quarterly, 42:1197–1232, 1950.
[30] A.C. Sekhara Reddy, S. Rajesham, and P. Ravinder Reddy. Evaluation of limiting drawing ratio (LDR) in deep drawing by rapid determination method. International Journal of Current Engineering and Technology, 4(2):757–762, 2014.
[31] R.U. Kumar. Analysis of Fukui’s conical cup test. International Journal of Innovative Technology and Exploring Engineering, 2(2):30–31, 2013.
[32] Ł. Kuczek, W. Muzykiewicz, M. Mroczkowski, and J. Wiktorowicz. Influence of perforation of the inner layer on the properties of three-layer welded materials. Archives of Metallurgy and Materials, 64(3):991–996, 2019. doi: 10.24425/AMM.2019.129485.
[33] O. Engler and J. Hirsch. Polycrystal-plasticity simulation of six and eight ears in deep-drawn aluminum cups. Materials Science and Engineering: A, 452–453:640–651, 2007. doi: 10.1016/j.msea.2006.10.108.
[34] M. Koç, J. Culp, and T. Altan. Prediction of residual stresses in quenched aluminum blocks and their reduction through cold working processes. Journal of Materials Processing Technology, 174(1-3):342–354, 2006. doi: 10.1016/j.jmatprotec.2006.02.007.
[35] C.S.T. Chang, I. Wieler, N. Wanderka, and J. Banhart. Positive effect of natural pre-ageing on precipitation hardening in Al–0.44 at% Mg–0.38 at% Si alloy. Ultramicroscopy, 109(5):585–592, 2009. doi: 10.1016/j.ultramic.2008.12.002.
[36] S. Jin, T. Ngai, G. Zhang, T. Zhai, S. Jia, and L. Li. Precipitation strengthening mechanisms during natural ageing and subsequent artificial aging in an Al-Mg-Si-Cu alloy. Materials Science and Engineering: A, 724:53–59, 2018. doi: 10.1016/j.msea.2018.03.006.
[37] E. Ishimaru, A. Takahashi, and N. Ono. Effect of material properties and forming conditions on formability of high-purity ferritic stainless steel. Nippon Steel Technical Report. Nippon Steel & Sumikin Stainless Steel Corporation, 2010.
[38] E.H. Atzema. Formability of auto components. In R. Rana and S.B. Singh (eds.): Automotive Steels. Design, Metallurgy, Processing and Applications. Woodhead Publishing, pages 47–93, 2017. doi: 10.1016/B978-0-08-100638-2.00003-1.
Go to article

Authors and Affiliations

Łukasz Kuczek
1
ORCID: ORCID
Marcin Mroczkowski
1
ORCID: ORCID
Paweł Turek
1

  1. AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Cracow, Poland
Download PDF Download RIS Download Bibtex

Abstract

Mechanical properties of the pipeline samples that had been cut in annular and axial directions were investigated. The methodology of modeling and calculation of the real stress-strain state was described. The stable state during in the deformation process was defined. The results of the experimental researches were used as a test variant during examination of pipe strength.

Go to article

Authors and Affiliations

Jerzy Małachowski
Volodymyr Hutsaylyuk
Petr Yukhumets
Roman Dmitryenko
Grigorii Beliaiev
Ihor Prudkii
Download PDF Download RIS Download Bibtex

Abstract

Bełchatów lignite deposit is located in the central partof Poland in the tectonic Kleszczów graben. It is dividedinto several parts, which are mining fields: Kamieńsk area (eastern part of the deposit), Bełchatów area (central partof the deposit) and Szczerców area (western part of the deposit). The subject of this study was the Belchatow area.The main issue of the investigations was the dependence of local, regional and global, horizontal variability of selected lignite qualitative parameters (moisture, ash content, calorific value and sulfur content in the as receivedstate) is a function of viewing direction. There was applied the geostatistical analysis of the lignite variability parameters with use of semivariograms.

The researches which were conducted at different scales of observation: in the locale scale – in small field size8 ́8 m called experimental area (local analysis), in larger homogeneous separated parts of the Belchatow area(regional analysis) and in the whole Bełchatów area scale (general analysis). The results proved the visible anisotropy of variability mine lignite parametres. Anisotropy structure observed in regional and global scale isconnected with tectonic structure of the Bełchatów Graben. The detailed studies show the variated level of anisotropy observed in different areas of Bełchatów field.

However, no dependence of the relative level of ash and total sulfur content anisotropy on the environment of sedimentation of the main coal deposit in different parts of the Belhchatów field has been observed. Both parameters characterize with strong or medium anisotropy level in examined fields. Moreover, anisotropy is alsovisible in the local scale. Conducted researches confirmed the thesis that zonal anisotropy is prevalent kind of anisotropy in the regional scale. In the range of the whole deposit the total sulfur content showed zonal anisotropy,whereas the ash content revealed geometric anisotropy

Go to article

Authors and Affiliations

Tomasz Bartuś
Download PDF Download RIS Download Bibtex

Abstract

The main purpose of the paper is to present a method which allows taking into account the anisotropic properties of dynamo steel sheets. An additional aim is to briefly present anisotropic properties of these sheets which are caused by occurrences of some textures. In order to take into account textures occurring in dynamo sheets, a certain sheet sample is divided into elementary segments. Two matrix equations, describing changes of the magnetic field, are transformed to one non-linear algebraic equation in which the field strength components are unknown. In this transformation the flux densities assigned to individual elementary segments are replaced by functions of flux densities of easy magnetization axes of all textures occurring in the given dynamo sheet. The procedure presented in the paper allows determining one non-linear matrix equation of the magnetic field distribution; in this equation all textures occurring in a dynamo sheet are included. Information about textures occurring in typical dynamo sheets may be used in various approaches regarding the inclusion of anisotropic properties of these sheets, but above all, the presented method can be helpful in calculations of the magnetic field distribution in anisotropic dynamo sheets.

Go to article

Authors and Affiliations

Witold Mazgaj
ORCID: ORCID
Zbigniew Szular
Michał Sierżęga
ORCID: ORCID
Paweł Szczurek
Download PDF Download RIS Download Bibtex

Abstract

In the past ten years, InAs/InAsSb type-II superlattice has emerged as a promising technology for high-temperature mid-wave infrared photodetector. Nevertheless, transport properties are still poorly understood in this type of material. In this paper, optical and electro-optical measurements have been realised on InAs/InAsSb type-II superlattice mid-wave infrared photodetectors. Quantum efficiency of 50% is measured at 150 K, on the front side illumination and simple pass configuration. Absorption measurement, as well as lifetime measurement are used to theoretically calculate the quantum efficiency thanks to Hovel’s equation. Diffusion length values have been extracted from this model ranging from 1.55 µm at 90 K to 7.44 µm at 200 K. Hole mobility values, deduced from both diffusion length and lifetime measurements, varied from 3.64 cm²/Vs at 90 K to 37.7 cm²/Vs at 200 K. The authors then discuss the hole diffusion length and mobility variations within temperature and try to identify the intrinsic transport mechanisms involved in the superlattice structure.
Go to article

Authors and Affiliations

Maxime Bouschet
1 2
Vignesh Arounassalame
3
Anthony Ramiandrasoa
3
Jean-Philippe Perez
1
Nicolas Péré-Laperne
2
Isabelle Ribet-Mohamed
3
Philippe Christol
1

  1. IES, Université de Montpellier, CNRS, 860 Saint Priest St., F-34000 Montpellier, CEDEX 5, France
  2. LYNRED, BP 21, 364 de Valence Ave., 38113 Veurey-Voroize, France
  3. ONERA, Chemin de la Hunière, F-91761 Palaiseau Cedex, France
Download PDF Download RIS Download Bibtex

Abstract

The aim of the paper is to formulate physically well founded yield condition for initially anisotropic solids revealing the asymmetry of elastic range. The initial anisotropy occurs in material primarily due to thermo-mechanical pre-processing and plastic deformation during the manufacturing processes. Therefore, materials in the “as-received” state become usually anisotropic. After short account of the known limit criteria for anisotropic solids and discussion of mathematical preliminaries the energy-based criterion for orthotropic materials was formulated and confronted with experimental data and numerical predictions of other theories. Finally, possible simplifications are discussed and certain model of isotropic material with yield condition accounting for a correction of shear strength due to initial anisotropy is presented. The experimental verification is provided and the comparison with existing approach based on the transformed-tensor method is discussed.

Go to article

Authors and Affiliations

R.B. Pęcherski
A. Rusinek
T. Fras
M. Nowak
Z. Nowak
Download PDF Download RIS Download Bibtex

Abstract

In this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable to reproduce mixed variable stress-induced anisotropy and constant inherent cross-anisotropy of the small strain stiffness. The degradation of stiffness depending on strain is modelled with the Brick-type model. The model formulation and parameters are briefly presented. General deformation pattern obtained in the exemplary 2D boundary value problem of an open pit excavation is investigated considering different values of inherent cross-anisotropy coefficient of small strain stiffness. The numerical simulations are performed as a coupled deformation-flow analysis which allows to properly model the drainage conditions. The excavation phases are simulated by removal of soil layers according to the realistic time schedule. Finally, the monitored case of the trial open pit excavation in heavily overconsolidated Oxford Clay at Elstow, UK is simulated with proposed material model both in 2D and 3D conditions. The obtained calculation results are compared with displacement measurements and discussed.
Go to article

Authors and Affiliations

Katarzyna Lisewska
1
ORCID: ORCID
Marcin Cudny
1
ORCID: ORCID

  1. Gdansk University of Technology, Faculty of Civil and Environmental Engineering, ul. Gabriela Narutowicza 11/12, 80-233 Gdansk, Poland

This page uses 'cookies'. Learn more