Nach oben pdf Multi-material simulation with the Material Point Method

Multi-material simulation with the Material Point Method

Multi-material simulation with the Material Point Method

Die Material Point Method (MPM) hat sich in der Computergrafik als äußerst fähige Simulationsmethode erwiesen, die in der Lage ist ansonsten schwierig zu animierende Materialien zu modellieren [1, 2]. Abgesehen von der Simu- lation einzelner Materialien stellt die Simulation mehrerer Materialien und ihrer Interaktion weitere Herausforderungen bereit. Dies ist Thema dieser Arbeit. Es wird gezeigt, dass die MPM durch die Fähigkeit Eigenkollisio- nen implizit handzuhaben ebenfalls in der Lage ist Kollisionen zwischen Objekten verschiedenster Materialien zu beschreiben, selbst, wenn verschie- dene Materialmodelle eingesetzt werden. Dies wird dann um die Interaktion poröser Materialien wie in [3] erweitert, was ebenfalls gut mit der MPM integriert. Außerdem wird gezeigt das MPM auf Basis eines einzelnen Gitters als Untermenge dieses Mehrgitterverfahrens betrachtet werden kann, sodass man das gleiche Verhalten auch mit mehreren Gittern modellieren kann. Die poröse Interaktion wird auf beliebige Materialien erweitert, einschließlich eines frei formulierbaren Materialinteraktionsterms. Das Resultat ist ein fle- xibles, benutzersteuerbares Framework das unabhängig vom Materialmodell ist. Zusätzlich wird eine einfache GPU-Implementation der MPM vorgestellt, die die Rasterisierungspipeline benutzt um Schreibkonflikte aufzulösen. An- ders als andere Implementationen wie [4] ist die vorgestellte Implementation kompatibel mit einer Breite an Hardware.
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Inelastic material response in multi-physics earthquake rupture simulations

Inelastic material response in multi-physics earthquake rupture simulations

The dynamics and potential size of earthquakes depend crucially on rupture transfers between ad- jacent fault segments. To accurately describe earthquake source dynamics, numerical models can account for realistic fault geometries and rheologies such as nonlinear inelastic processes off the slip interface. We present implementation, verification, and application of off-fault Drucker-Prager plasticity in the open source software SeisSol (www.seissol.org). SeisSol is based on an arbi- trary high-order derivative modal Discontinuous Galerkin (ADER-DG) method using unstructured, tetrahedral meshes specifically suited for complex geometries. Two implementation approaches are detailed, modelling plastic failure either employing sub-elemental quadrature points or switching to nodal basis coefficients. At fine fault discretizations the nodal basis approach is up to 6 times more ef- ficient in terms of computational costs while yielding comparable accuracy. Both methods are verified in community benchmark problems and by three dimensional numerical h- and p-refinement studies with heterogeneous initial stresses. We observe no spectral convergence for on-fault quantities with respect to a given reference solution, but rather discuss a limitation to low-order convergence for het- erogeneous 3D dynamic rupture problems. For simulations including plasticity, a high fault resolution may be less crucial than commonly assumed, due to the regularization of peak slip rate and an increase of the minimum cohesive zone width. In large-scale dynamic rupture simulations based on the 1992 Landers earthquake, we observe high rupture complexity including reverse slip, direct branching, and dynamic triggering. The spatio-temporal distribution of rupture transfers are altered distinctively by plastic energy absorption, correlated with locations of geometrical fault complexity. Computational cost increases by 7% when accounting for off-fault plasticity in the demonstrating application. Our results imply that the combination of fully 3D dynamic modelling, complex fault geometries, and off-fault plastic yielding is important to realistically capture dynamic rupture transfers in natural fault systems.
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A simulation-based method for improving material efficiency within the constraints of existing production systems

A simulation-based method for improving material efficiency within the constraints of existing production systems

strategy II aims to reduce consumer demand for goods from raw virgin materials, therefore lessening the demand for material extraction. This includes the approaches of light-weighting, component re-use, and using recycled materials in manufacturing. Unlike the first two strategies, strategy III assumes an unchanged consumer demand for material goods and focusses on lessening the demand for material extraction and materials manufacturing by reducing the waste caused by these process stages. The fields of action include reducing gross material requirements, using less material intensive manufacturing processes, and improving industrial yield. Strategy IV seeks to reduce the environmental repercussions through material substitution, including using less toxic materials and less energy intensive materials. The application of these four strategies results in a less intense, loss-free material flow to the consumer or service provider and the reintroduction of end-of life products as late in the supply chain as possible. This vision is in- line with the circular economy concept; however, this thesis will focus on strategy III, since it is the only strategy compatible with set product program and process specifications.
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Multi-material design in welding arc additive manufacturing

Multi-material design in welding arc additive manufacturing

Figure 8. Metallographic grinding of the modified fillet weld. Samples with a thickness of 5 mm were taken out by milling from the fillet welds for investigations under fatigue using the notch stress concept. The tests were carried out on a resonance testing machine of the type Rumul Testronik 110 kN (Russenberger Prüfmaschinen AG, Neuhaus am Rheinfall, Switzerland). The T-sample is loaded by bending, Figure 6 . This causes a local tensile load in the seam transition area in the area of a metallurgical and geometric notch. These fatigue samples were then tested under cyclic bending up to fracture with the help of a resonance testing machine under the stress ratio R = 0.1. The calculation of the notch stresses was carried out by means of FEM (finite element method) simulation based on the procedure presented in Eurocode3–9.
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Inverse Estimation Method of Material Randomness Using Observation

Inverse Estimation Method of Material Randomness Using Observation

In this study, a method of inversely estimating the correlation distance was proposed using measurement (observation), and it was confirmed that the actual correlation distance (d) agreed well with the estimated actual distance. Therefore, we could overcome the current disadvantage and find the true result of the actual structure, and not the assumption. Incidentally, the proposed method has a temporal advantage over the response variance. Verification was performed using an example by assuming that the program running time was 1 min at a time. A total of 100,000 (= 1000 ×1 ×100) minutes of program running time is required in order to analyze 1000 samples per correlation distance for COV from d = 1~100. This means a decrease in the number of interpretations of the Monte-Carlo simulation, and the program running time was reduced to a total of 1000 (= 1000 ×1 ×1) minutes.
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Atomistic simulations for material processes within multiscale method

Atomistic simulations for material processes within multiscale method

Atomistic simulation technique such as first-principles, molecular dynam- ics and Monte Carlo methods has been recognised as a powerful engineering tool to design a new functional material. It serves as the most fundamental procedure to construct a reliable and integral multiscale simulation frame- work, as well as gives the mechanisms behind the characteristic property and process at atomic scale. In this work some attempts to realize a kind of multiscale simulation have been carried out, paying attention to the nec- essary information availabe from smaller scale simulations for larger scale simulations. Firstly, an efficient first-principles approach with virtual crys- tal approximation has been proposed for calculating the material properties of solid solutions within density functional theory. The capability of the previous approaches was extended to treat a virtual atom composed of the heterovalent atoms with reasonable accuracy. The results for the perovskite structure ferroelectric solid solution, x BiScO 3 –(1-x )PbTiO 3 , which contains
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Theory and Numerical Modeling of Geomechanical Multi-material Flow

Theory and Numerical Modeling of Geomechanical Multi-material Flow

tinct materials separated by sharp material interfaces undergo large de- formations. The research presented in this paper addresses a particular class of multi-material flow situations encountered in geomechanics and geotechnical engineering which is characterized by a complex coupled behavior of saturated granular material as well as by a hierarchy of dis- tinct spatial scales. Examples include geotechnical installation processes, liquefaction-induced soil failure, and debris flow. The most attractive numerical approaches to solve such problems use variants of arbitrary Lagrangian-Eulerian descriptions allowing interfaces and free surfaces to flow through the computational mesh. Mesh elements cut by inter- faces (multi-material elements) necessarily arise which contain a hetero- geneous mixture of two or more materials. The heterogeneous mixture is represented as an effective single-phase material by using mixture the- ory. The paper outlines the specific three-scale mixture theory developed by the authors and the MMALE numerical method to model and sim- ulate geomechanical multi-material flow. In contrast to traditional flow models which consider the motion of multiple single-phase materials or single multi-phase mixtures, the present research succeeds in incorpo- rating both the coupled behavior of saturated granular material and its interaction with other (pure) materials.
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Cutting simulation with consideration of the material hardening in the Shear Zone of AISI1045

Cutting simulation with consideration of the material hardening in the Shear Zone of AISI1045

the force-displacement behaviour of the nano indentation experiments. Due to the inhomogeneity of the hardness values caused by the ferrite-perlite structure the reference was averaged over the nano indentation points in the chip above the shear zone. The procedure corresponds to the method of B OBZIN ET AL . [4]. The indenter is considered as a rigid body. The material model of the workpiece material is based on the model that was used for the simulations within the previous investigations [6, 9]. The flow curves used in this model were obtained by compression tests with a Rastegaev geometry with different strain rates [6, 12]. A more detailed description of the material model is described by U HLMANN ET AL . [6]. The flow curves were integrated as mathematical functions in the subroutines of DEFORM. In order to depict the material hardening in the shear zone the flow curves were modified
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A convex analysis approach to multi-material topology optimization.

A convex analysis approach to multi-material topology optimization.

This work is concerned with optimal control of partial differential equations where the control enters the state equation as a coefficient and should take on values only from a given discrete set of values corresponding to available materials. A “multi- bang” framework based on convex analysis is proposed where the desired piecewise constant structure is incorporated using a convex penalty term. Together with a suitable tracking term, this allows formulating the problem of optimizing the topology of the distribution of material parameters as minimizing a convex functional subject to a (nonlinear) equality constraint. The applicability of this approach is validated for two model problems where the control enters as a potential and a diffusion coefficient, respectively. This is illustrated in both cases by numerical results based on a semi- smooth Newton method.
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Multi-material topology optimization for composite metal aircraft structures

Multi-material topology optimization for composite metal aircraft structures

Figure 9 Aluminum occupies 7% of the design domain Figure 6 to Figure 9 show the topology optimization process of the hybrid structure. It is a relatively simple implementation of level set based method. As the volume fraction of aluminum decreases, aluminum tends to accumulate in regions with the highest strain energy. Also, the complex geometries at the joints which are not easily achieved by using MMC solely are easily formed by level sets. As a result, the obtained structure has the following advantages: Firstly, the material ratio is still controllable in case the total material cost needs to be optimized against the compliance. Secondly, the geometry features are controllable by constraint the width function as a constant. In this way, the manufacturability of the hybrid structure is ensured and the cost to build this structure is minimized. Most importantly, this routine embedded some logic in the conventional topology optimization by distributing specific materials in specific regions.
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Multi-equation modelling of desirable and undesirable outputs satisfying the material balance

Multi-equation modelling of desirable and undesirable outputs satisfying the material balance

literature. It is assumed that the secondary residual has the same form as the primary residual, e.g. measured in CO 2 , or SO 2 , or in the form determined by the combustion process or production process in general. In order to express the residual variables in the same unit, we can convert abatement residuals z a , typically given another form than the primary residual, into units of primary residual applying a conversion coefficient δ and then do a simple subtraction shown in the second equation in (10). It is assumed that the abated residuals do not create any environmental damage. The feasible range of modification is from zero to 1. It is typically the case that at least all gaseous residuals cannot be dealt with completely and modified to harmless substances, so z   z a  z D  0 . A limit around 95 % is often mentioned in practice for the ratio for e.g. flue-gas desulphurisation. The partial productivities in the abatement production function are assumed positive. Increases in the abatement inputs contribute to an increase in the relative share of abated amount and an absolute increase for a given amount of primary residual. Given the amount of the primary residual from the production stage knowing the rate of abatement A both the absolute amounts of the two abatement outputs can be calculated:  z a  Az z , D   (1 A z ) . Applying the materials balance principle in the last equation of (10) the abatement activity will add to the total mass of residuals if material inputs are used, but the point is that abatement means less mass of the harmful residual; z D < z. The conversion coefficient for the material input is now a’ that in general is different from a, and likewise b’ is in general different from b. The c coefficient is the same as in (6). The conversion coefficients measure the common substance in all variables in the same unit, e.g. weight (not accounting the substances in the residuals added from the air during the combustion). The mass of the primary residual on the left-hand side is now functioning as an input. The right-hand side shows where the mass ends up.
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A Multi-Objective Optimization Approach for Bulk Material Blending Systems

A Multi-Objective Optimization Approach for Bulk Material Blending Systems

This thesis is focused on longitudinal blending beds as illustrated in figure 2.3. The blending bed is an area allocated for building so-called stockpiles of raw material. The blending bed can have a typical length up to 1000 m and a width up to 50 m. The bed is located between two rail tracks on which huge stacking and reclaiming machines move along the bed which can be seen in the figures 2.5 and 2.4 published on [sta13, rec13]. The stacking machine is fed with the input bulk stream using a conveyor belt. The reclaimer collects the bulk material on one end of the stockpile and feeds it to a conveyor belt moving to the plant. The stacking machine has a long arm which reaches over the middle of the blending bed where the material is deposited. The material is then stacked to stockpiles by layering it with so-called cone-shell or chevron stacking methods [BCW00]. For instance using the chevron stacking method the material is layered in horizontal levels. Defined by the speed of the stacking machine and the material flow the levels become thicker or thinner. The bridge reclaiming machine ablates the material in diagonal layers. If the stockpile was stacked using the chevron stacking method the cross sections ablated diagonally contain material of all levels. The blending result correlates mostly with the amount of layers and hence with the speed of the stacking machine but is also influenced byte the material quality curve shape as illustrated in detail in section 5.4.
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Solving Material Mechanics and Multiphysics Problems of Metals with Complex Microstructures Using DAMASK—The Düsseldorf Advanced Material Simulation Kit

Solving Material Mechanics and Multiphysics Problems of Metals with Complex Microstructures Using DAMASK—The Düsseldorf Advanced Material Simulation Kit

To create RVE that incorporate the complex features of DP steels, Tata Steel has developed a microstructure generation tool which is based on the multi-level Voronoi tessellation [128] and has been enriched with additional features. In contrast to the stan- dard Voronoi tessellation, which is only capable of creating convex shaped cells (i.e., grains), the multi-level algorithm makes it possible to create complex-shaped grains. Moreover, different size and spa- tial distributions for ferrite grains and martensite inclusions can be generated. More details of the tool can be found in refs. [129,130]. In the study presented here, the in fluence of the spatial dis- tribution of martensite particles and their orientations on hard- ening behavior and the r-value is investigated. 2D electron backscatter diffraction (EBSD) data from an industrial DP600 steel grade forms the basis for building 3D microstructures. Figure 14 shows the measured microstructure colored according to the inverse pole and the ferrite grain size distribution. The area fraction of martensite was determined as 11.7%. The orientation distributions of ferrite and martensite are shown in Figure 15. For the RVE generation, the phase volume fraction, ferrite and martensite orientation distribution, ferrite and martensite size distribution, as well as the spatial distribution of martensite has been used. To determine the volume fraction of martensite from the area fraction the simple stereological formula dV i
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Lebensdauerabschätzung hybrid gefügter Multi-Material Feinblechverbindungen

Lebensdauerabschätzung hybrid gefügter Multi-Material Feinblechverbindungen

Due to increasingly restrictive emission limits, the automotive industry is forced to find new solu- tions to reduce weight. One way of reducing weight is to use different materials in body development. In contrast to conventional welding, new joining techniques such as self-piercing riveting (SPR) en- able an assembly of such dissimilar material combinations. But to fully exploit the lightweight po- tential it is important to represent and evaluate joints correctly in CAE calculations. Since both spot welds and SPRs are local circular joints, it appears reasonable to adapt and modify already estab- lished methods for spot welds to estimate the fatigue life of SPRs. Therefore, the numerical assess- ment of the riveted joints is developed using a structural stress approach. A major challenge here is to represent the behavior of different materials in the SPR joints. With material-specific SN curves and an adapted stress calculation, the estimated fatigue life shows a good agreement with the exper- imental results. The fatigue life of the adhesively bonded connections is estimated by a stress-based approach as well. The stresses from additionally modeled shell layers on the free areas of the solid adhesive elements in the finite element simulation are proposed as the main cause for the crack ini- tiation of the adhesive layer. A regression through the calculated stress values and the fatigue life leads to the reference SN curve with a low scatter. The developed methods are validated and evalu- ated on component-level specimens. It is also shown that the fatigue life of the hybrid joined con- nections can be estimated by superposing the contributing fatigue lives of the purely SPR and purely adhesive joints.
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Mode II Delamination Analysis of Asymmetrical Four Point Bend Layered Beams with Considering Material Non-linearity

Mode II Delamination Analysis of Asymmetrical Four Point Bend Layered Beams with Considering Material Non-linearity

The stedy-state delamination fracture behaviour of multilayered beams has been analyzed assuming linear-elastic material behaviour by Hsueh et al., 2009. The fracture has been studied in terems of the strain energy release rate by applying the classical beam theory. A closed form analytical solution has been derived for a delamination crack located arbitrary along the beam height. The solution can be used for multilayered beam configurations with any number of layeres. Besides, each layer can have individual thickness and modulus of elasticity.
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Material and Methods 

Material and Methods 

mice. Each group represents the mean of 6 to 8 experi­ ments and the vertical bars indicate the s.e.m. * * P < 0.01 com pared with corresponding control value. which presented ID 50 of 133 and 125 mmol/kg, ip, respectively, in the same experimental model (Gaertner et al., 1999). The antinociceptive effect was observed over a long time period, extending its action until 4 hours after the algesic stimuli with acetic acid (Fig. 2). When the animals were treated

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Raw material markets

Raw material markets

Terms of use: Documents in EconStor may be saved and copied for your personal and scholarly purposes. You are not to copy documents for public or commercial purposes, to exhibit the documents publicly, to make them publicly available on the internet, or to distribute or otherwise use the documents in public.

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Regionale Material- und Energieflußrechnungen

Regionale Material- und Energieflußrechnungen

§ In der aktivitätsbezogenen Rechnung wird das Aufkommen und die Verwendung von Material und Energie dargestellt, die von den Aktivitäten der 58 Produktionsbereiche der inländischen Wirtschaft sowie der Haushalte ausgehen. Unter einem Produktionsbereich ist dabei die Gesamt- heit aller wirtschaftlichen Aktivitäten, die ausschließlich und vollständig die Güter einer Güter- gruppe erzeugen, zu verstehen. Durch die Verwendung der Gliederung nach homogenen Produk- tionsbereichen können die Daten zu umweltrelevanten Material- und Energieströmen sowie zu Umweltbelastungen direkt in Beziehung zu ökonomischen Kennziffern aus der Volkswirtschaft- lichen Gesamtrechnung gesetzt werden. Produktionsbereiche stellen somit das Bindeglied zwischen Wirtschafts- und Umweltdaten dar.
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Raw material markets

Raw material markets

Terms of use: Documents in EconStor may be saved and copied for your personal and scholarly purposes. You are not to copy documents for public or commercial purposes, to exhibit the documents publicly, to make them publicly available on the internet, or to distribute or otherwise use the documents in public.

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Enhancing Material Nature

Enhancing Material Nature

The foregoing discussion has been restricted to the area of new materials, an area that, while important for nano research, is still rather limited in view of the larger ambitions associated with nanotechnologies. In contrast to this, the programmes of nanobiotechnology and synthetic biology open a huge gulf between accomplished research and envisioned application. Especially in synthetic biology the intent is to merge technology and nature and thus to go beyond nature with technical means. One perhaps extreme vision speaks of plants with black silicon leaves whose purpose is to gather and store energy (Dyson 2007). Such envisioned syntheses express the aspiration of a technological convergence (VDI 2003) that is enabled by nanotechnologies' indifferent manipulation of all molecular structure: by surpassing the distinction between the organic and the inorganic, between the natural and the artificial, molecular recombinations are to enable the fusion of plants and solar panels. This programme of technological convergence is dedicated by no means to human enhancement, in particular, but includes, for another example, visions of using information technology to penetrate and enhance all ecosystems (Banfield 2002).
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