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Wyświetlanie 1-15 z 21
Tytuł:
Numerical implementation of finite strain elasto-plasticity without yield surface
Autorzy:
Suchocki, C.
Powiązania:
https://bibliotekanauki.pl/articles/949335.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
constitutive equation
tangent moduli
UMAT
plasticity
Opis:
In the present study, the finite element (FE) implementation of elasto-plasticity without a yield surface is discussed. For that purpose, the method of perturbing the deformation gradient tensor is employed to calculate approximate tangent moduli. The development of a user subroutine that enables one to use the proposed model within the FE program ABAQUS is covered. A number of exemplary numerical simulations is conducted in order to check the performance of this subroutine. Material parameter values determined for different materials are utilized. Finally, the presented constitutive equation is examined upon its ability to capture the shear-softening process.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 4; 1113-1126
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hypoplastic modelling of pre-failure behaviour of sand against experimental data
Autorzy:
Głębowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/241400.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
hypoplasticity
constitutive equation
sand
deformation
anisotropy
Opis:
The aim of this article is to compare experimentally determined strains of sand with theoretical calculations made on the base of the theory of hypoplasticity. During the study `Skarpa' sand was examined in the triaxial apparatus with local measurement of vertical and lateral strains. Results obtained were used to calibrate 8-parameter von Wolffersdorff model. Subsequently, the behaviour of loose and dense sandy samples subjected to different stress paths was predicted.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 1; 31-47
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of material parameters of quasi-linear viscoelastic rheological model for thermoplastics and resins
Autorzy:
Suchocki, C.
Pawlikowski, M.
Skalski, K.
Jasiński, C.
Morawiński, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/281326.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
rheology
constitutive equation
quasi-linear viscoelasticity
Opis:
In this study, an algorithm for identification of elastic and viscoelastic constants of a recently developed constitutive equation for thermoplastics and resins is presented. The equation has been applied to model the viscoelastic response of ultra high molecular weigth polyethylene. In order to determine the material parameters, a series of rheological tests has been performed. A set of equations describing one-dimensional processes has been derived and is utilized to determine the material constants. The material parameter identification leads to a set of 9 constants, i.e. 3 constants of elasticity and 6 constants of viscoelasticity. For the determined values of parameters, several validation tests have been performed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 569-580
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite strain formulation of elasto-plasticity without yield surface: theory, parameter identification and applications
Autorzy:
Suchocki, C.
Skoczylas, P.
Powiązania:
https://bibliotekanauki.pl/articles/281580.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
constitutive equation
plasticity
metals
material constants
Opis:
In this study, a finite strain formulation of elasto-plasticity without the yield surface is analyzed. It is found that the presented model allows for a good description of the elasto-plastic response for many metallic materials. Furthermore, it is noted that the model involving a limited number of material parameters is able to capture such effects as indefinite elastic limit, strain hardening, strain softening and the Bauschinger effect. An algorithm for the evaluation of constants is described and the determined values are given for NC high carbon tool steel, copper, brass, Inconel alloy, tungsten heavy alloy and aluminum.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 731-742
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introduction to hypoplasticity (GeoMath1)
Autorzy:
Kolymbas, D.
Powiązania:
https://bibliotekanauki.pl/articles/1954567.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
granular materials
yield
hysteresis
dilatancy
constitutive equation
Opis:
Rational mechanics offers a tool to objectively describe the mechanical behaviour of granular materials by means of non-linear tensorial functions. This new framework is called hypoplasticity and is characterized by the simplicity of the mathematical formulations. The stress dependency of incremental stiffness, yield, loading-unloading hysteresis and dilatancy-contractancy are included. One of the features of hypoplasticity is that yield is a natural outcome of the theory and needs not be calibrated a priori. Also loss of uniqueness and localization of deformation are realistically predicted by hypoplasticity.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 343-366
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deformations and stability of granular soils: Classical triaxial tests and numerical results from an incremental model
Autorzy:
Sławińska-Budzich, Justyna
Mierczyński, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/178180.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
constitutive equation
granular soils
deformation
instability
stability
Opis:
This article presents a modified incremental model describing pre-failure deformations of granular soils under classical triaxial conditions. The original shape of equations has been proposed by Sawicki and Świdziński [40, 41]. A new form of equations that are consistent with the proposed definitions of deviatoric loading and unloading is suggested. Triaxial tests necessary for calibrating the proposed model have been performed. The modified model is used to simulate the deformations and stability of sand for every pre-failure loading path and makes it possible to describe the behaviour of granular soil under both drained and undrained conditions. A comparison of experimental and numerical results is presented. All investigations were performed in a classical tri-axial apparatus.
Źródło:
Studia Geotechnica et Mechanica; 2020, 42, 2; 137-150
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An internal-state-variable based viscoelastic-plastic model for polymers
Autorzy:
Suchocki, C.
Powiązania:
https://bibliotekanauki.pl/articles/279925.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
polymers
rheology
constitutive equation
finite element method
Opis:
In this study, a new viscoelastic-plastic constitutive model which has been formulated by utilizing the formalism of stress-like internal state variables is introduced. The developed constitutive equation allows for a good description of the inelastic material response of polymeric materials over a wide range of strain rates. An algorithm for numerical integration of the model equations has been derived. The FE implementation of the constitutive equation is widely discussed and the results of solving several exemplary problems are presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 593-604
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D and 2D Formulations of Incremental Stress-Strain Relations for Granular Soils
Autorzy:
Sawicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/241028.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
granular soils
pre-failure deformations
instability
anisotropy
constitutive equation
Opis:
3D formulation of incremental relations, describing pre-failure deformations of granular soils, is presented. The starting point are respective equations formulated previously for the axi-symmetrical configuration, as that in the tri-axial apparatus. These relations, proposed for particular configuration, are generalized in the form of tensor equations for the strain increments. Similarly, the loading/unloading criterion and the instability line have been generalized for 3D conditions. A kind of cross-isotropy of granular soil is taken into account. Then, the incremental stress-strain relations for the plane strain state are re-derived from general equations, as such conditions are most often used for simulations of practically important problems. The procedure proposed in this paper is practically oriented, as the soil parameters can be determined just from the tri-axial tests.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2008, 55, 1-2; 45-53
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress distribution in front of the crack – analytical solutions vs. numerical. Can the differences be minimized?
Autorzy:
Neimitz, Andrzej
Lipiec, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/280865.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
stress distribution in front of crack
HRR
constitutive equation calibration
Opis:
It is shown that it is possible to obtain such parameters as α and Q, which, when used in the analytical formulae proposed by O’Dowd and Shih, can lead to stress distributions similar to those obtained numerically. The numerical solution obtained after calibration of the stress-strain uniaxial curve and assuming large strains is expected to be close to the “real” stress distribution. Thus, the analytical solution after correction is also close to the “real” stress distribution. These new values of α and Q can now be used in fracture criteria proposed within the scope of classical nonlinear fracture mechanics.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 713-721
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warm Tensile Deformation Behavior and Constitutive Equation of Supersaturated Solid-Solutionized Al-9Mg Extruded Alloy
Autorzy:
Yang, Seung Y.
Kim, Bong H.
Lee, Da B.
Choi, Kweon H.
Kim, Nam S.
Ha, Seong H.
Yoon, Young O.
Lim, Hyun K.
Kim, Shae
Kim, Young J.
Powiązania:
https://bibliotekanauki.pl/articles/2048882.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum alloy
Al-9Mg alloy
tensile test
constitutive equation
Opis:
In this paper, as a purpose to apply the supersaturated solid-solutionized Al-9Mg alloy to the structural sheet parts of automotive, tensile tests were conducted under the various conditions and a constitutive equation was derived from the tensile test results. Al-9Mg alloy was produced using a special Mg master alloy containing Al2Ca during the casting process and extruded into the sheet. In order to study the deformation behavior of Al-9Mg alloy in warm temperature forming environments, tensile tests were conducted under the temperature of 373 K-573 K and the strain rate of 0.001/s~0.1/s. in addition, by using the raw data obtained from tensile tests, a constitutive equation of the Al-9Mg alloy was derived for predicting the optimized condition of the hot stamping process. Al-9Mg alloy showed uncommon deformation behavior at the 373 K and 473 K temperature conditions. The calculated curves from the constitutive equation well-matched with the measured curves from the experiments particularly under the low temperature and high strain rate conditions.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1013-1018
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A quasi-linear viscoelastic rheological model for thermoplastics and resins
Model reologiczny quasi-liniowej lepkosprężystości dla termoplastów i żywic
Autorzy:
Suchocki, C.
Powiązania:
https://bibliotekanauki.pl/articles/279870.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
polymers
rheology
constitutive equation
quasi-linear viscoelasticity
finite element method
Opis:
A new rheological model for polymeric materials has been proposed. The model is based on the concept of utilizing the Knowles stored-energy potential within the framework of quasi-linear viscoelasticity theory. The quasi-linear viscoelastic constitutive equation in its general form has been formulated using the formalism of the internal state variables. The developed constitutive equation allows for capturing the nonlinear-viscoelastic behavior of many polymeric materials such as thermoplastics or resins. The model has been implemented into a FE system. An application of the developed constitutive equation to modeling of the short-term, dissipative response of polyethylene has been presented.
Zaproponowano nowy model reologiczny dla materiałów polimerowych. Model bazuje na koncepcji wykorzystania funkcji potencjalnej energii akumulowanej typu Knowlesa w ramach teorii quasi-liniowej lepkosprężystości. Równanie konstytutywne quasi-liniowej lepkosprężystości w ogólnej postaci sformułowano, wykorzystując formalizm wewnętrznych zmiennych stanu. Opracowane równanie konstytutywne pozwala na opis nieliniowo lepkosprężystych własności wielu materiałów polimerowych, takich jak termoplasty czy żywice. Model wprowadzono do systemu MES. W pracy zaprezentowano zastosowanie opracowanego równania konstytutywnego do modelowania krótkookresowej i dyssypatywnej odpowiedzi polietylenu.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 117-129
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyper-elastic modelling of intervertebral disc polyurethane implant
Autorzy:
Pawlikowski, M.
Skalski, K.
Sowiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/306535.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
constitutive equation
curve fitting
hyper-elastic constants
równanie konstytutywne
dopasowywanie krzywej
Opis:
Artificial materials including various kinds of polymers like polyurethanes are more and more widely used in different branches of science and also in biomedical engineering. The paper presents the process of creating a constitutive equation for a polyurethane nanocomposite which is considered to be hyper-elastic. The constitutive modelling was conducted within the range of application of the material as one of the components of lumbar intervertebral disc prosthesis. In the paper, the biomechanics of the lumbar spine and the most frequently applied intervertebral disc prostheses are described. Also a polyurethane nanocomposite as a new material to be applied in prostheses is presented. The way of formulating a constitutive equation by means of mathematical formulae is described. Four various hyper-elastic potential functions are considered, i.e., Ogden, Neo-Hookean, Yeoh and Mooney–Rivlin. On the basis of monotonic compression tests the best hyper-elastic model for the material considered was chosen and hyper-elastic constants were calibrated. Finally, the constitutive model was validated on the basis of FE analysis. The paper ends with a conclusion and presentation of further plans of research directed towards the development of a constitutive equation and its application in computer simulations by means of the finite element method.
Źródło:
Acta of Bioengineering and Biomechanics; 2013, 15, 2; 43-50
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comprehensive constitutive equation for granular materials
Autorzy:
Gudehus, G.
Powiązania:
https://bibliotekanauki.pl/articles/1954568.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
constitutive equation of soil
critical state
deformation
granular materials
stability analysis
Opis:
constitutive equation is proposed for describing changes of states of granular materials, which are sufficiently characterised by the void ratio and the stress tensor. It may be considered as an extension of the Critical State concept. It is based on recently published hypoplastic equations and covers a wide range of densities, pressures and deformations. A factorial decomposition allows a rather easy separation and determination of material parameters. Two factors depend on a relative void ratio so that it remains within lower and upper bounds. The bounding void ratios decrease monotonously from maximal values to zero with increasing pressure. The same reduction of the void ratio is proposed for an isotropic compression starting from a suspension. Thus a granulate hardness is defined, and a stiffness factor can be determined. Four material parameters can be estimated from classification tests and determined from the asymptotic behaviour in element tests. Four further parameters are determined by calibration; they are rather constant for wide groups of materials. Strength and stiffness values can be derived and used for the analysis of deformations, stability, and flow. The viscous behaviour is modelled by a rate dependent factor with one further parameter. Limitations and possible extensions of this comprehensive approach are also outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 319-342
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the high-temperature behaviour of aluminium alloy EN AW 2014
Wysokotemperaturowe zachowanie stopu aluminium EN AW 2014
Autorzy:
Bidulská, J.
Pokorný, I.
Kvačkaj, T.
Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/352627.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stopy aluminium
naprężenie płynięcia
równanie konstytutywne
aluminium alloy
flow stress
constitutive equation
hot working
Opis:
The high-temperature behaviour of aluminium alloy EN AW 2014 was investigated in a wide range of deformation temperatures and strain rates. The influence of strain rate and temperature on the peak stress was analysed using the conventional constitutive equation (relating strain rate, flow stress, and temperature) and by means of precise definition of the peak stress value, in the non-linear regression model. Moreover, a study on apparent activation energy of EN AW 2014 stabilized by zirconium was carried out using Arrhenius-type plot. The stress-strain curves exhibit rapid increase up to the peak value followed by a gradual softening up to the material fracture, without the steady state usually observed before the fracture. In terms of formability maps, the presented experimental results exhibit a decrease of ductility, respectively with an increase of strain rate and a decrease of temperature, respectively.
Wysokotemperaturowe zachowanie stopu aluminium EN AW 2014 badane było w szerokim zakresie temperatur i predkości odkształcenia. Wpływ prędkości odkształcenia i temperatury na maksymalne naprężenie analizowany był z użyciem konwencjonalnego podstawowego równania (wiazacego predkość odkształcenia, naprezenie płyniecia i temperature) oraz za pomocą precyzyjnej definicji wartości maksymalnego naprężenia w modelu regresji nieliniowej. Ponadto, analiza obserwowanej energii aktywacji stopu EN AW 2014 stabilizowanego cyrkonem przeprowadzono z użyciem wykresu typu Arrheniusa. Krzywe naprężenie-odkształcenie wykazują gwałtowny wzrost do maksymalnego naprężenia, po którym następuje stopniowe mięknięcie aż do zerwania materiału, bez obszaru stałego zwykle obserwowanego przed zerwaniem. Jesli chodzi o mapy plastycznosci, przedstawione wyniki doświadczalne wykazują spadek plastycznosci, odpowiednio ze wzrostem szybkości odkształcenia oraz ze spadkiem temperatury.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 4; 981-981
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelowanie i analiza numeryczna procesu cięcia blach karoseryjnych z uwzględnieniem efektów termicznych
Modelling and numerical analysis of the autobody sheet cutting regarding thermal effects
Autorzy:
Bohdal, Ł.
Kukiełka, L.
Powiązania:
https://bibliotekanauki.pl/articles/317317.pdf
Data publikacji:
2013
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
modelowanie
cięcie
MES (metoda elementów skończonych)
równanie konstytutywne Johnsona-Cooka
modeling
cutting
FEM
Johnson-Cook constitutive equation
Opis:
W artykule przedstawiono sposób modelowania procesu cięcia blach karoseryjnych z wykorzystaniem metody elementów skończonych z uwzględnieniem wpływu temperatury na naprężenia uplastyczniające materiału. W celu analizy rozkładów naprężeń i odkształceń w czasie trwania i po procesie, opracowano trójwymiarowy model numeryczny procesu cięcia na gilotynie w środowisku Ansys/LS-Dyna z wykorzystaniem metody explicit. Do opisu własności ciętego materiału wykorzystano równanie konstytutywne Johnsona-Cooke’a. Otrzymano mapy intensywności naprężeń i odkształceń dla dowolnej chwili czasowej z uwzględnieniem nieliniowości występujących w procesie. Przedstawiono wybrane wyniki analizy numerycznej, które mogą być wykorzystane do projektowania procesu i jego optymalizacji.
In this paper, the modelling of the autobody sheet cutting process regarding the influence of temperature on the yield stress was presented. For the purpose to states of stresses and strains analysis during and after the process 3D model of guillotining process was built in Ansys/LS-Dyna code. Johnson-Cook’s constitutive equation was used for the description of the properties of the sheet cut. Obtained results can be used for the purpose of designing cutting process and its optimization.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2013, 14, 10; 38-42
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 21

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