Wyniki wyszukiwania - Biblioteka Nauki

1

Modelling of production chains as a tool for intelligent manufacturing in metal forming

100%

Madej L. , Weglarczyk S. , Rauch L. , Pietrzyk M.

Journal of Machine Engineering

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2008

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tom Vol. 8, No. 2

33--42

EN

The objective of the paper is demonstration of the role of multi scale modelling in the system, which optimizes the whole production chain. Product exploitation and properties are the key parameters for formulation of the objective function in the optimization problem. Such parameters as fatigue resistance, wear resistance or thermal resistance are crucial for extending the life cycle of products, therefore, theoretical prediction of those parameters is inevitable for the optimization of the manufacturing system. Thus, the main focus in the paper is on description of the idea of multi scale modelling and on presentation of the multi scale model developed by the Authors. This model combines finite element (FE) solution of the macro scale problem with the cellular automata (CA) model of the micro scale phenomena. Simulation of the production chain is the second part of the paper. The chain under consideration is composed of stock heating, cold forging, machining and simulation of exploitation conditions. The correlation between the process parameters and the exploitation properties of the product is demonstrated. Finally, the optimization problem which would be the base of intelligent manufacturing, is formulated.

2

Stochastic finite element analysis of transient heat transfer in composite materials with interface defects

70%

Kamiński M. , Hien T.

Archives of Mechanics

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1999

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tom Vol. 51, nr 3-4

399-418

EN

The paper presented is devoted to the application of the probabilistic computational analysis based on the stochastic finite element methods in the transient heat transfer problems; the field of application of the method introduced is the mechanics of composite materials. The composite materials considered have randomly defined thermal characteristics and, moreover, the interface discontinuities appearing between constituents have a probabilistic character. The influence of all these parameters on the first two probabilistic moments of temperature are verified on the example of a two-component layered composite with an interphase between the constituents.

3

Stiffness degradation in gradient-dependent coupled damage-plasticity

70%

Pamin J. , de Borst R.

Archives of Mechanics

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1999

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tom Vol. 51, nr 3-4

419-446

EN

Two gradient-dependent combinations of isotropic plasticity and scalar damage are proposed. The gradient enhancements of either the plasticity or the damage component of the theory are performed by introducing the Laplacian of a strain measure and an internal length parameter. This makes the constitutive models applicable to localization analyses. The models are used for finite element simulations of localization in a one-dimensional tensile bar problem. The coupling of hardening/softening plasticity with damage governed by different damage evolution functions is discussed. Then, attention is focused on the response of the models in unloading from localized deformation states. The model of gradient damage combined with hardening plasticity is used to predict progressive damage of concrete in a beam subjected to four-point bending. The simulated stiffness degradation is compared with experimental results.

4

Dynamic failure mechanism of copper foil in laser dynamic flexible forming

70%

Shen Z. , Zhang L. , Li P. , Liu K. , Lin Y. , Zhou G. , Wang Y. , Zhang J. , Liu H. , Wang X.

Materials Science Poland

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2020

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tom Vol. 38, No. 4

684--692

EN

Laser dynamic flexible forming (LDFF) is a novel high velocity forming (HVF) technology, in which the foil metal is loaded by laser shock wave. Strain localization is readily to occur around the bulge edge, which will result in the ultimate dynamic failure. In this work, the microstructures before and after dynamic fracture are characterized by transmission electron microscopy (TEM) to investigate the dynamic failure mechanism. The plastic deformation regions of copper foil are composed of shock compression, strain localization and bulge. Microstructure refinement was observed in three different plastic deformation regions, particularly, dynamic recrystallization (DRX) occurs in the strain localization and bulge regions. In bulge region, extremely thin secondary twins in the twin/matrix (T/M) lamellae are formed. The microstructure features in the strain localization region show that superplastic flow of material exists until fracture, which may be due to DRX and subsequent grain boundary sliding (GBS) of the recrystallized grains. The grain coarsening in strain localization region may degrade the material flowing ability which results in the dynamic fracture.

5

Experimental investigations of strain localization in concrete using Digital Image Correlation (DIC) technique

70%

Kozicki J. , Tejchman J.

Archives of Hydro-Engineering and Environmental Mechanics

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2007

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tom Vol. 54, nr 1

3-24

EN

The paper presents results of experimental investigations of strain localization in concrete using a non-destructive method called Digital Image Correlation (DIC) technique. This technique measures surface displacements from digital images. The model tests were carried out with notched concrete specimens under three-point bending. Three different beam sizes and two different concrete mixes were used. During experiments, load--deflection curves and evolution of fracture process zone were determined. The measured size effect in strength was compared with the deterministic size effect law by Bazant (1984) and experimental results by Le Bellégo et al (2003).

6

Analysis of strain localization in porous media with transversely isotropic elasticity under undrained conditions

70%

Zhang Y. Q. , Wang L. Z. , Pang M. , Fan L. F.

Journal of Theoretical and Applied Mechanics

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2017

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tom Vol. 55 nr 1

199--211

EN

The properties of strain localization for elastic-plastic porous media with transversely isotropic elasticity under undrained conditions are investigated. Under non-associated plasticity and tri-axial stress states, the conditions for strain localization of elastic-plastic porous media are derived, in which the effects of deviation from isotropic elasticity and pore fluid compressibility are included. Based on the Mohr-Coulomb yield criterion, the influences of the deviation from isotropic elasticity and pore fluid compressibility on the direction angle of localized band initiation and the corresponding critical hardening modulus for the case of plane strain are discussed. As a result, the properties of strain localization are dependent upon the deviation from isotropic elasticity and pore fluid compressibility. The deviation from isotropic elasticity and pore fluid compressibility has significant impacts on the direction angle of localized band initiation and the corresponding critical hardening modulus.

7

Concurrent and upscaling methods in multi scale modelling - case studies

60%

Madej Ł. , Mrozek A. , Kuś W. , Burczyński T. , Pietrzyk M.

Computer Methods in Materials Science

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2008

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tom Vol. 8, No. 1

1-15

EN

Selected examples of applications of multi scale modeling in various areas of mechanics and materials science are presented in the paper. Advantages and disadvantages of these approaches are shown. Based on the literature review a classification of multi scale methods into two groups was pointed out. The first is upscaling group based on representative volume element. The second is concurrent group, where the method used to describe the fine scale is usually applied to a part of the whole domain of the solution. Detailed discussion of these two groups is based on the multi scale models developed by the Authors. The concurrent model is based on the combination of the molecular dynamic with the boundary element method and is applied to simulation of material failure. The upscaling model is called CAFE and is based on the combination of the cellular automata with the finite element method. Applications of this model to prediction strain localization in materials subjected to plastic deformation are also demonstrated in the paper.

PL

W pracy zaprezentowano dynamicznie rozwijające się nowe metody obliczeniowe do analizy wieloskalowej, umożliwiające opis zjawisk zachodzących w materiale, niemożliwych do przewidywania tradycyjnymi metodami modelowania. Dokonano klasyfikacji metod na dwie grupy różniące się sposobem podejścia do symulacji w różnych skalach oraz do interakcji między nimi. Pierwsza z nich to grupa metod hierarchicznych, która bazuje na reprezentatywnym elemencie objętości. Druga grupa to metody symulujące dane zjawisko w całej lub w części objętości badanego materiału równocześnie w kilku skalach. Przyjęto nazywać je metodami hybrydowymi odzwierciedlając współbieżne prowadzenie obliczeń różnymi metodami w przeciwieństwie do metod hierarchicznych, gdzie obliczenia prowadzone są w reprezentacyjnych elementach objętości. Opisano interesujące modele bazujące na połączeniu metod analizy mikro np. Automatów Komórkowych (ang. CA), Monte Carlo (ang. MC) czy Dynamiki Molekularnej (ang. MD) z metodami analizy makro np. Metodą Elementów Skończonych (ang. FE) czy też Metodą Elementów Brzegowych (ang. BE). Przykłady tworzenia i zastosowania modeli hierarchicznych i hybrydowych w zastosowaniu do symulacji zjawisk zachodzących w materiale podczas odkształcania przedstawiono bazując na połączeniu metod CA i FE oraz MD i BE.

8

Modeling of strain localization in quasi-brittle materials with a coupled elasto-plastic-damage model

60%

Bobiński J. , Tejchman J.

Journal of Theoretical and Applied Mechanics

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2006

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tom Vol. 44 nr 4

767-782

EN

The paper presents results of numerical simulations of strain localization in quasi-brittle materials (like concrete) under plane strain conditions. To model the material behaviour, an isotropic elasto-plastic-damage model combining elasto-plasticity and scalar damage was used. An elasto-plastic constitutive law using a Drucker-Prager yield surface (in compression) and Rankine yield surface (in tension) was defined. A modified failure criterion by Rankine for the equivalent strain using an exponential evolution law was assumed within damage mechanics. To obtain mesh-independent results of strain localization, the model was enhanced by non-local terms in the softening regime. A four-point bending test of a concrete beam with a single notch was numerically simulated using the finite element method. FE-results were compared with laboratory experiments.

PL

W artykule przedstawiono wyniki symulacji numerycznych lokalizacji odkształceń w materiałach quasi-kruchych (jak beton) w płaskim stanie odkształcenia. Do opisu materiału przyjęto izotropowy model sprężysto-plastyczno-zniszczeniowy uwzględniający prawo sprężysto-plastyczne ze skalarną degradacją sztywności. W przypadku prawa sprężysto-plastycznego przyjęto kryterium plastyczności Druckera-Pragera w ściskaniu i kryterium plastyczności Rankine'a w rozciąganiu. Degradację sprężystą opisano z wykorzystaniem definicji odkształcenia zastępczego wegług warunku Rankine'a i wykładniczym prawem ewolucji. W celu otrzymania wyników niezależnych od siatki elementów skończonych, w obszarze osłabienia przyjęto teorię nielokalną. Przedstawiono wyniki symulacji numerycznych dla belki betonowej z nacięciem obciążonej dwoma siłami skupionymi. Wyniki numeryczne porównane z wynikami doświadczalnymi.

9

Umocnienie odkształceniowe materiału w próbach jedno- oraz dwuosiowego rozciągania blach

60%

Stachowicz F.

Rudy i Metale Nieżelazne

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2007

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tom R. 52, nr 11

722-727

PL

Przebiegi zależności naprężenie-odkształcenie blach stalowych, aluminiowych oraz mosiężnych zostały wyznaczone w próbach jednoosiowego rozciągania oraz dwuosiowego równomiernego rozciągania (wybrzuszanie hydrauliczne). Przeprowadzona została analiza rozkładu grubości blachy w różnych punktach czaszy uformowanej podczas wybrzuszania hydraulicznego. Zarówno wartość średnia wykładnika krzywej umocnienia n (opisująca skłonność do umocnienia w całym zakresie odkształcenia), wyznaczona przy zastosowaniu równania Hollomona, jak również jego wartości chwilowe nt (zależne od wielkości odkształcenia materiału), zostały wyznaczone na podstawie wyników prób jedno- oraz dwuosiowego rozciągania. Przeanalizowano wpływ stanu odkształcenia na wartości chwilowe wykładnika krzywej umocnienia oraz na proces lokalizacji odkształcenia dla obydwu rodzajów testów.

EN

The stress-strain relationship of the steel, aluminium and brass sheets were determined by uniaxial and balanced biaxial (hydraulic bulging) tensile tests. Sheet thickness gradation in different points of hemisphere formed in bulge test was analyzed. Both the mean value of strain hardening exponent n (which describe the strain hardening of the whole strain range) according to the Hollomon equation and differential nt-value were determined on the base of the results of uniaxial and biaxial testing. The influence of the stress-state on the value of differential strain hardening exponent, as well as strain localization process, under both deformation modes was analyzed.

10

Wpływ stanu metalurgicznego i sposobu odkształcenia na strukturę i teksturę stopu AA7075

60%

Stalony-Dobrzański F. , Pieła K. , Błaż L. , Ostachowski P.

Rudy i Metale Nieżelazne

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2010

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tom R. 55, nr 2

99-107

PL

W artykule poddano analizie relację między obrazem tekstury, uzyskanym z precyzyjnego pomiaru dyfraktometrycznego, a strukturą walcowanego stopu AA7075. Wykazano, że zarówno sposób walcowania (jednokierunkowy lub ze zmianą kierunku walcowania o 90 stopni - tzw. "krzyżowy"), jak również stan metalurgiczny stopu (przesycony lub homogenizowany) determinują typ formowanej tekstury. W przypadku materiału w stanie przesyconym, zmiany tekstury można rozpatrywać jako rezultat lokalizacji plastycznego płynięcia w pasmach ścinania, powodującego "fragmentację" stopu na bloki, zachowujące się jak quasi-monokryształy. Prowadzi to do tekstury, opisywanej jako tekstura typu metalu lub typu stopu tworzącej się w wyniku walcowania odpowiednio: jednokierunkowego lub krzyżowego. W stopie homogenizowanym deformacja plastyczna jest realizowana przez homogenicznie dystrybuowane drobne, cienkie pasma poślizgu (mikropasma ścinania), co niezależnie od sposobu walcowania skutkuje formowaniem się tekstury "mieszanej" (typu metalu + typu stopu).

EN

The relation between the texture analyzed by means of precise diffractometric method, and the structure of cold rolled AA7075 aluminum alloy was discussed. It was stated that both the deformation mode, i.e. unidirectional rolling or crossrolling, and the initial metallurgical state (supersaturated or homogenized material) determine the kind of the formed texture. Observed change of the texture for the supersaturated and cold rolled alloy can be considered as a result of plastic flow localization and shear bands development, which causes the "fragmentation" of material into the blocks, behaving like quasi-single crystals. As a result, the texture called as a metal-type or an alloy-type, are created during unidirectional rolling or cross-rolling, respectively. On the other hand, the plastic deformation of homogenized material is accompanied by the development of uniformly distributed fine slip bands (microshear bands), which leads to the formation of "mixed" texture (metal type + alloy type) for the two tested modes of rolling procedure.

11

Fe analysis of strain localization in concrete in elasto-plasticity and damage mechanics with non-local softening

60%

Bobiński J.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2006

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tom Vol. 10, No 4

353-375

EN

Results of Finite Element Method (FEM) simulations of a strain localization in concrete specimens are presented. Two different continuum approaches have been used to model to behaviour of concrete: (i) an elasto-plastic constitutive law with the Drucker-Prager criterion in the compression regime and the Rankine criterion in the tensile regime, with isotropic hardening and softening and (ii) an isotropic continuum damage model with the equivalent strain corresponding to the Rankine failure criterion and modified Huber-Mises criterion in terms of strains, with exponential softening. Both constitutive models were enriched by non-local terms to describe strain localization properly, ensure mesh-independence in the softening regime and capture the deterministic size effect. The constitutive models were used to simulate strain localization in concrete in two boundary value problems under plane strain conditions, viz. uniaxial tension and three-point bending. The effect of the characteristic length on load-displacement curves and widths of strain localization is discussed.

12

Notched concrete beams under bending -- calculations of size effects within stochastic elasto-plasticity with non-local softening

60%

Bobiński J. , Tejchman J. , Górski J.

Archives of Mechanics

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2009

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tom Vol. 61, nr 3-4

283-307

EN

Numerical FE investigations of a deterministic and statistical size effect in notched concrete beams of a similar geometry under three-point bending were performed. The FE analyses were carried out with four different beam sizes. Deterministic calculations were performed assuming constant values of tensile strength. In turn, in statistical calculations, the tensile strength took the form of random spatial fields described by a truncated Gaussian random distribution. In order to reduce the number of stochastic realizations without loosing the accuracy of the calculations, Latin hypercube sampling was applied. The numerical results were compared with the corresponding laboratory tests. The numerical outcomes show that the bearing capacity of beams and their ductility increase with decreasing specimen size. If the distribution of the tensile strength is stochastically distributed, the mean beam strength is always smaller than the deterministic value.

13

Numerical simulations of strain localization for large strain damage - plasticity model

60%

Wcisło B. , Pamin J.

Computer Methods in Materials Science

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2013

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tom Vol. 13, No. 2

231--237

EN

This paper deals with the phenomenon of strain localization in nonlinear and nonlocal material models. Particularly, in the description of the material not only nonlinear constitutive relations (damage, plasticity) are included, but also geometrical nonlinearities (large strains) are taken into account. The strain localization in the analysed model has a twofold source: geometrical effects (necking) and softening due to damage of the material. To avoid pathological mesh sensitivity of numerical test results the gradient averaging is applied in the damage model. The material description is implemented within the finite element method and numerical simulations are performed for a uniaxial tensile bar benchmark. Selected results are presented for the standard and regularized continuum.

PL

Artykuł dotyczy zjawiska lokalizacji odkształceń w nieliniowych i nielokalnych modelach materiałowych. W szczególności, przedstawiony opis materiału zawiera nie tylko nieliniowe związki konstytutywne (uszkodzenie, plastyczność), ale również nieliniowości geometryczne (duże odkształcenia). Lokalizacja odkształceń w analizowanym modelu ma dwojakie źródło: efekty geometryczne (szyjkowanie) oraz osłabienie spowodowane uszkodzeniem materiału. Zastosowanie standardowych modeli continuum nie prowadzi do poprawnej symulacji zachowania materiałów z osłabieniem. Spowodowane jest to utratą eliptyczności równań równowagi, gdy zależność między naprężeniami a odkształceniami wchodzi na ścieżkę opadającą. W takim przypadku odkształcenia lokalizują się w najmniejszej możliwej objętości materiału, która w symulacji numerycznej określona jest przez rozmiar elementu skończonego. Aby uniknąć patologicznej zależności wyników testów numerycznych od dyskretyzacji należy zastosować odpowiednią regularyzację. W niniejszej pracy zastosowano uśrednianie gradientowe, w którym istotną rolę odgrywa wewnętrzna skala długości. Jest to dodatkowy parametr materiału związany z jego mikrostrukturą, który może określać szerokość strefy lokalizacji odkształceń. W artykule przedstawiono zwięźle opis analizowanego modelu sprężysto-plastycznego sprzężonego z uszkodzeniem przy dużych odkształceniach oraz zastosowanej regularyzacji gradientowej. Model ten został oprogramowany w pakiecie Ace- Gen w środowisku Mathematica oraz przetestowany przy użyciu pakietu AceFEM. W pracy zaprezentowane są wybrane wyniki symulacji rozciągania pręta dla różnych wariantów przyjętego opisu materiału, w których można zaobserwować lokalizację odkształceń zarówno związaną z osłabieniem materiału jak i osłabieniem geometrycznym.

14

Instabilities in membrane tension: Parametric study for large strain thermoplasticity

60%

Mucha M. , Wcisło B. , Pamin J. , Kowalczyk-Gajewska K.

Archives of Civil and Mechanical Engineering

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2018

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tom Vol. 18, no. 4

1055--1067

EN

This paper deals with the numerical analysis of localized deformation for a rectangular plate in membrane tension, modelled with large strain thermoplasticity. The aim is to determine the influence of selected factors on the localization phenomena, which can result from geometrical, material, and thermal softening. Two types of boundary conditions are considered: plane stress and plane strain, as well as two yield functions, Huber–Mises–Hencky and Burzyński–Drucker–Prager, with selected values of friction angle. First, isothermal conditions are considered and next, a conductive case with thermal softening is studied. Moreover, three types of plastic behaviour are analysed: strain hardening (with different values of hardening modulus), ideal plasticity, and strain softening. Numerical tests, performed using AceGen/FEM packages, are carried out for the rectangular plate under tension with an imperfection, using three finite element discretizations. The results for plane strain in the isothermal model show that with the decrease of linear hardening modulus, we can observe stronger mesh sensitivity, while for plane stress, mesh sensitivity is visible for all cases. Furthermore, for the thermomechanical model the results also depend on the mesh density due to insufficient heat conduction regularization.

15

Enhanced coupled elasto-plastic-damage models to describe concrete behaviour in cyclic laboratory tests: comparison and improvement

51%

Marzec I. , Tejchman J.

Archives of Mechanics

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2012

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tom Vol. 64, nr 3

227-227

EN

The paper presents two-dimensional FE simulation results of the concrete behaviour under quasi-static cyclic loading using different enhanced coupled elasto-plastic-damage continuum models. Attention is paid to strain localization and stiffness degradation under tensile bending failure. To ensure the mesh-independence, to properly reproduce strain localization and to capture a deterministic size effect, all constitutive models include a characteristic length of micro-structure by means of a non-local theory. Numerical results are compared with corresponding cyclic laboratory tests on concrete specimens under bending. Advantages and disadvantages of coupled models used are outlined. In addition, numerical aspects of implementation and non-local averaging of coupled models are discussed. Finally, a new improved model is proposed to describe strain localization simultaneously under both tension and compression.

16

Investigation of strain rate sensitivity of Gum Metal under tension using digital image correlation

51%

Golasiński K. , Pieczyska E. , Maj M. , Staszczak M. , Świec P. , Furuta T. , Kuramoto S.

Archives of Civil and Mechanical Engineering

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2020

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tom Vol. 20, no. 2

339--352

EN

Mechanical behavior of a multifunctional titanium alloy Gum Metal was investigated by conducting tensile tests at various strain rates and applying digital image correlation (DIC) technique. Stress–strain curves confirmed low Young’s modulus and high strength of the alloy. The determined values of yield strength had a tendency to increase, whereas the elongation to the specimen rupture tended to decrease with increasing strain rate. True stress versus strain curves were analyzed using selected lengths of virtual extensometer (VE) placed in the strain localization area. When the initial length of the VE was the same as the gauge length, work hardening was observed macroscopically at lower strain rates, and a softening was seen at higher strain rates. However, the softening effect was not observed at the shorter VE lengths. Evolution of the Hencky strain and rate of deformation tensor component fields were analyzed for various strain rates at selected stages of Gum Metal load-ing. The DIC analysis demonstrated that for lower strain rates the deformation is macroscopically uniform up to the higher average Hencky strains, whereas for higher strain rates the strain localization occurs at the lower average Hencky strains of the deformation process and takes place in the smaller area. It was also found that for all strain rates applied, the maximal values of Hencky strain immediately before rupture of Gum Metal samples were similar for each of the applied strain rates, and the maximal local values of deformation rate were two orders higher when compared to applied average strain rate values.

17

Komputerowe modelowanie procesów przetwórstwa metali - analiza wieloskalowa

51%

Pietrzyk M. , Madej Ł. , Żmudzki A.

Hutnik, Wiadomości Hutnicze

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2005

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tom Vol. 72, nr 4

238-246

PL

W pierwszej części artykułu przedstawiono wybrane przykłady symulacji przeprowadzonych z wykorzystaniem metody elementów skończonych. Przykłady dotyczą przewidywania rozwoju mikrostruktury podczas procesów plastycznej przeróbki z uwzględnieniem rzeczywistego stanu termomechanicznego. W drugiej części pracy zaprezentowano opracowywane nowe podejście, oparte na analizie wieloskalowej, umożliwiające skuteczną symulację odkształcenia z uwzględnieniem zjawisk zachodzących w skali mikro. Analiza taka umożliwia uzyskiwanie informacji o szeregu zjawisk zachodzących na różnym poziomie w rozpatrywanym materiale i w konsekwencji umożliwia szczegółową interpretację wyników.

EN

Several examples of computer simulations based on the finite element method are shown in the first part of the paper. The work is focused on the microstructure development during plastic deformation accounting for the thermo-mechanical phenomena. An alternative approach, the multiscale modelling of localization phenomena, is presented in the second part. This analysis is crucial for simulation of the processes, which take place in different scales in the material. As a consequence a detail interpretation of these phenomena is achieved.

18

Application of the Digital Material Representation to strain localization prediction in the two phase titanium alloys for aerospace applications

51%

Muszka K. , Madej L. , Wynne B. P.

Archives of Civil and Mechanical Engineering

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2016

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tom Vol. 16, no. 2

224--234

EN

In the present work Digital Material Representation (DMR) approach was utilized to simulate the deformation behavior of the two phase Ti-6Al-4V alloy. DMR models of the two phase structure, containing different morphologies of alpha grains within a beta matrix – lamellar and equiaxed, were created. Each phase was then separated and different mechanical properties were assigned. Subsequently, their response to loading was tested using simple shear numerical simulations with special focus on strain inhomogeneities, as the main driving force for spheroidization is considered to be the formation of intense shearing within alpha lamellae. The proposed modeling approach combining Finite Element Method (FEM) with DMR allowed for much more detailed numerical analysis of deformation behavior of two phase titanium alloys at the micro scale and provided information such as strain localization and stress distributions within the alpha and beta phases. It was showed that presented model offers a new and powerful tool to study the physical bases of microstructure evolution processes such as spheroidization or recrystallization of Ti alloys. It shows good potential in simulation of deformation processes of complex two-phase morphologies that is a crucial step towards optimization of process parameters during hot forming of Ti-6Al-4V alloys.

19

Digital Materials - nowe kierunki rozwoju symulacji numerycznej procesów przetwórstwa metali

51%

Gawąd J. , Kusiak J. , Pietrzyk M. , Rauch Ł. , Madej Ł.

Hutnik, Wiadomości Hutnicze

|

2007

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tom Vol. 74, nr 4

208-216

PL

W pracy omówiono nowoczesne metody analizy procesów zachodzących w metalach i stopach podczas przeróbki plastycznej, wykorzystujące metodę analizy wieloskalowej CAFE (Cellular Automata in Finite Element). Szczególny nacisk położono na wykorzystanie zalet cyfrowej reprezentacji materiału, pozwalającej wiernie odwzorować rzeczywistą mikrostrukturę z jej cechami charakterystycznymi, stwarzając nową jakość symulacji numerycznej. W artykule przedstawiono przegląd dotychczasowych zastosowań koncepcji cyfrowej reprezentacji materiału oraz propozycję własnego rozwiązania w tej dziedzinie. Zaprezentowano również opis tworzenia cyfrowej struktury materiału opierając się na rzeczywistym zdjęciu z mikroskopu optycznego oraz możliwości wykorzystania tak przygotowanej struktury w opracowanych modelach analizy wieloskalowej CAFE.

EN

Application of new multi scale CAFE (Cellular Automata in Finite Element) models to numerical simulation of material behaviour during deformation processing is the subject of the paper. Particular attention is put on investigation of capabilities created by the digital material representation approach. This approach provides a possibility for detailed description of microstructure taking into account its specific features. Literature review on application of the digital material methodology, as well as proposition of the model developed by the Authors based on this idea, are presented in the work. Entire cycle of generation of the digital structure from the optical microscope image, as well as possibilities of its further application in developed multi scale CAFE models, are discussed in the paper.

20

Computational modelling of localized deformations with regularized continuum models

51%

Pamin J.

Mechanics and Control

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2011

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tom Vol. 30, no. 1

27-33

EN

The paper presents a short overview of selected problems related to the numerical analysis of localized deformations. After defining the localization phenomenon and the class of gradient models, two simulation examples are shown. They are applications of the plasticity theory with a Laplacian of the hardening parameter and of the damage theory with an additional averaging equation for an equivalent strain measure.

PL

Artykuł przedstawia krótki przegląd wybranych problemów analizy numerycznej deformacji zlokalizowanych. Po zdefiniowaniu zjawiska lokalizacji i klasy modeli gradientowych zwięźle opisano dwa przykładowe zastosowania teorii płynięcia plastycznego zawierającej laplasjan parametru wzmocnienia i teorii uszkodzenia z dodatkowym równaniem uśredniającym miarę odkształcenia w otoczeniu punktu.