Dominik Brands

Dominik Brands
University of Duisburg-Essen | uni-due · Institut für Mechanik

Dr.-Ing.
Post-Doctoral Researcher (akad. Oberrat); Team Leader Scientific Computing

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65
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Publications

Publications (65)
Article
The development of an elasto-plastic phase-field model is presented which is able to predict nonlinear behavior of high performance concrete (HPC) during low-cycle fatigue. An elasto-plastic damage model which follows the Drucker–Prager yield criterion is formulated. For the modeling of unsymmetric tension–compression behavior of HPC two different...
Article
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We construct two-dimensional, two-phase random heterogeneous microstructures by stochastic simulation using the planar Boolean model, which is a random collection of overlapping grains. The structures obtained are discretized using finite elements. A heterogeneous Neo-Hooke law is assumed for the phases of the microstructure, and tension tests are...
Article
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This contribution aims to analyze the deterioration behaviour of steel fibre-reinforced high-performance concrete (HPC) in both experiments as well as numerical simulations. For this purpose, flexural tensile tests are carried out on beams with different fibre contents and suitable damage indicators are established to describe and calibrate the dam...
Article
The influence of reinforced steel fiber on the failure behavior of high performance concrete (HPC) is mainly characterized by the complex fiber-matrix interaction at microscale. A phenomenological material model is developed for more efficient simulation of the overall material behavior of fiber reinforced HPC. For the calibration of the material p...
Article
The direct consideration of residual stresses can positively influence the properties of a component and offers a new perspective compared to the typical strategy of avoiding residual stresses. Instead of minimizing residual stresses in forming processes, their consideration can positively influence the properties of the final component. For instan...
Article
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Zusammenfassung Ziel dieser Arbeit ist die Einstellung eines vorteilhaften Druckeigenspannungsprofils in warmumgeformten Bauteilen durch intelligente Prozessführung mit angepasster Abkühlung aus der Schmiedewärme. Die Machbarkeit und das Potenzial werden an einem Warmumformprozess, bei dem zylindrische Proben mit exzentrischer Bohrung bei 1000 °C u...
Article
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The resulting shapes in production processes of metal components are strongly influenced by deformation induced residual stresses. Dual-phase steels are commonly used for industrial application of, e.g., forged or deep-drawn structural parts. This is due to their ability to handle high plastic deformations, while retaining desired stiffness for the...
Article
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In this contribution, the two-scale analysis of residual stress states in a hot bulk formed part with subsequent cooling in the framework of the $$\hbox {FE}^2$$ FE 2 -method is presented. The induction of specific residual stress states in order to improve a component’s properties is an area of current research. In general, residual stresses can b...
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In production engineering, current research focuses on the induction of targeted residual stress states in components in order to improve their properties. Therein, the combination of experiment and simulation plays an important role. In this contribution, a focus is laid on the investigation of hot forming processes with subsequent cooling. A nume...
Article
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In this contribution, ellipsoidal and hexagonal prism representative volume element (RVE) which characterize the steel fiber reinforced high performance concrete (HPC) along a preferred fiber direction are constructed and analyzed numerically. A virtual experiment is simulated using a microscopic boundary value problem based on two different RVEs....
Article
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For modeling the solid‐solid transformation using the phase‐field method, we need to describe the phase‐fields strain and stress fields in the interfacial regions which are necessary to define the mechanical driving force density of the phase‐fields motion. Seeking quantitative modeling, we introduce briefly a multi‐phase‐field elasticity model bas...
Article
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The consideration of residual stresses in forming processes is a promising opportunity to influence the final component's properties in a positive manner. Instead of their minimization, a targeted application of residual stresses can extend life time or durability and enhance manufacturability of metallic components. For this reason, detailed exper...
Article
The pseudo-ductile material behavior of fiber reinforced high performance concrete is mainly characterized by the fiber pullout process. Thereby, complex fiber-concrete interactions, i.e. interface debonding, concrete micro cracks, slippage, adhesion and further unknown processes, are commonly investigated in single-fiber pullout tests. The study i...
Chapter
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We present a numerical two-scale simulation approach of the Nakajima test for dual-phase steel using the software package FE2TI, a highly scalable implementation of the well known homogenization method FE2. We consider the incorporation of contact constraints using the penalty method as well as the sample sheet geometries and adequate boundary cond...
Article
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This study proposes a micromechanical modeling scheme to predict relevant mechanical behavior of DP600 steel for the sheet metal forming process. This study can be divided into two parts which are the prediction of the advanced anisotropic initial yield function by means of microstructure-based simulations and the investigation of microstructure ch...
Article
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The adjustment of targeted residual stress states is important in order to improve the properties of a component. Here, especially hot forming processes offer a meaningful potential since a number of parameters such as deformation state, temperature profile or cooling media can be adapted independently. This publication presents first simulation st...
Article
Full-text available
In this paper, the pullout behavior of steel fiber embedded in high‐performance concrete (HPC) is investigated. First, a constitutive framework of elasto‐plastic phase‐field model of fracture is constructed and applied to simulation of pullout tests for different embedded lengths of steel fibers. Thereby, the description of the mechanical behavior...
Article
This paper aims at extending the existing knowledge regarding the pull‐out behavior of single steel fibers embedded in high‐ and ultra‐high‐strength concretes with compressive strengths exceeding 100 MPa. Apart from the compressive strength, straight fibers, and fibers with hooked‐ends as well as different embedded lengths are considered. The exper...
Chapter
The aim of this contribution is to describe and analyse the pull-out behaviour of single steel fibres embedded in high-and ultra-high performance concrete (HPC and UHPC). To achieve this, experimental series are described as basis for numerical analyses using phase-field models. In the first part, several series of fibre pull-out tests are describe...
Article
Full-text available
Residual stresses in components are a central issue in almost every manufacturing process, as they influence the performance of the final part. Regarding hot forming processes, there is a great potential for defining a targeted residual stress state, as many adjustment parameters, such as deformation state or temperature profile, are available that...
Article
Dual‐Phase (DP) steels exhibit excellent macroscopic properties such as high strength, ductility and energy absorption. However, the increase of strength also results in a large springback behavior which should be considered for an optimal production process design. Thus, accurate modeling of springback during forming applications is important. The...
Article
A precise representation of the residual stresses, their development in numerical simulations as well as their interpretation in experimental results requires a profound knowledge of the thermal, mechanical as well as metallurgical properties of the considered material. This publication presents initial approaches for the calculation of residual st...
Article
For the generation of synthetic storms in order to estimate claims due to storm hazards there exist a couple of commercial tools. They are based on expert's knowledge and physical models of wind appearance or work with distortions of historical hazards. In contrast to these approaches we present a purely data driven model. From the historical data...
Article
In this contribution, a constitutive framework of elasto‐plastic phase‐field model for fracture is applied to simulation of pullout test of single steel fiber embedded in concretes and compare it to the experimental results. For the description of the mechanical behavior the Drucker‐Prager plasticity model is used. The aim is to examine the pullout...
Article
A method for constructing statistically similar representative volume elements (SSRVEs) for a real dual-phase (DP) steel microstructure is presented in this contribution. The advantageous material properties of such kind of steels originate from the interaction of the microstructure constituents of the material on the microscale. In order to captur...
Article
The microstructure of dual-phase steels consisting of a ferrite matrix with embedded martensite inclusions is the main contributor to the mechanical properties such as high ultimate tensile strength, high work hardening rate, and good ductility. Due to the composite structure and the wide field of applications of this steel type, a wide interest ex...
Article
In this paper an extended optimization procedure is proposed for the construction of statistically similar RVEs (SSRVEs) which are defined as artificial microstructures showing a lower complexity than the associated real microstructures. This enables a computationally efficient discretization required for numerical calculations of microscopic bound...
Article
A metallurgical material description of the flow behavior for finite element (FE) simulations was developed. During hot compression tests, the dynamic microstructure evolution is modeled on the example of high-strength martensitic steel MS-W 1200. Compression tests at 900–1000 °C with a strain rate of 0.1 1 s−1 on fine-grain and coarse-grain sample...
Article
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The magneto-electric (ME) coupling of multiferroic materials is of high interest for a variety of advanced applications like in data storage or sensor technology. Since the ME coupling of single-phase multiferroics is too low for technical applications, the manufacturing of composite structures becomes relevant. These composites generate the effect...
Article
In modern engineering, micro-heterogeneous materials are designed to satisfy the needs and challenges in a wide field of technical applications. The effective mechanical behavior of these materials is influenced by the inherent microstructure and therein the interaction and individual behavior of the underlying phases. Computational homogenization...
Article
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Advanced high strength steels, such as dual-phase steel (DP steel), provide advantages for engineering applications compared to conventional high strength steel. The main constituents of DP steel on the microscopic level are martensitic inclusions embedded in a ferritic matrix. A way to include these heterogeneities on the microscale into the model...
Chapter
In computational homogenization approaches the definition of a representative volume element (RVE) strongly influences the performance of the resulting numerical scheme, not only with respect to its physical accuracy but also with respect to the computational effort required. Here, we propose a method for the construction of statistically similar R...
Article
A method for the construction of three-dimensional statistically similar representative volume elements (SSRVEs) is presented. Since the beneficial material properties of microheterogeneous materials originate in the microstructure, its incorporation in material modeling is desired. The FE2 method is a suitable tool to accomplish this step. Applyin...
Article
In this paper a method is presented for the construction of two- and three-dimensional statistically similar representative volume elements (SSRVEs) that may be used in computational two-scale calculations. These SSRVEs are obtained by minimizing a least-square functional defined in terms of deviations of statistical measures describing the microst...
Article
This contribution presents a method for the construction of three-dimensional Statistically Similar Representative Volume Elements (SSRVEs) for dual phase steels (DP steels). From such kind of advanced high strength steels, enhanced material properties are observed, which originate in the interaction of the individual constituents of the material o...
Article
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This paper communicates perspectives and ideas for lengthscale-transitions for metallic materials from nano over micro to macro. For micro-macro transitions, the FE2-method is described, where a top-down perspective manifests the need to introduce even finer-scaled information than typically considered on the microscale, such as e.g. atomistic deta...
Article
This contribution presents a method to construct three-dimensional Statistically Similar RVEs (SSRVEs) for the simulation of dual phase steel (DP steel). Since the microstructure of DP steel strongly influences the overall material properties, it should be incorporated in numerical calculations. For this purpose the FE2 method can be applied and fo...
Article
The authors greatly appreciate the Deutsche Forschungsgemeinschaft (DFG) for the financial support under the research grant KL 2094/1 and SCHR 570/7. The authors also acknowledge the scientific support for assistance regarding the numerical calculations by S. Brinkhues (Institute of Mechanics, University Duisburg‐Essen, Germany) and J. Kownatzki (W...
Article
An increasing number of engineering structures in the fields of light weight constructions or automotive applications makes use of advanced high-strength steels. To optimize the overall mechanical behavior computer simulations taking into account the micro-heterogeneity of these materials have been becoming the major tool. Direct micro-macro-transi...
Article
In this contribution we reconstruct the three dimensional microstructure of a dual-phase steel based on the tomographic experimental data provided by the 3D electron backscatter diffraction (3D EBSD) method. The cross sections of the resulting microstructure are compared to the 2D reconstruction, which are obtained directly from the 3D EBSD data. W...
Article
For the direct incorporation of micromechanical information into macroscopic boundary value problems, the FE2-method provides a suitable numerical framework. Here, an additional microscopic boundary value problem, based on evaluations of representative volume elements (RVEs), is attached to each Gauss point of the discretized macrostructure. Howeve...
Article
Micrographs of a dual-phase steel obtained from a EBSD-FIB imaging are analyzed with respect to a set of statistical measures. Then the applicability of this data to the construction of statistically similar representative volume elements (SSRVEs) is discussed. These SSRVEs are obtained by minimizing a least-square functional taking into account di...
Article
In our contribution we discuss the applicability of statistically similar representative volume elements (SSRVEs) for the incorporation of microstructural information during multiscale simulations using the FE2-method. Such SSRVEs are characterized by a lower complexity than usual random representative volume elements (RVEs), but they represent qui...
Article
Full-text available
For the simulation of micro-heterogeneous materials the FE 2 -method provides incorporation of the mechanical behavior at the microscale in a direct manner by taking into account a microscopic boundary value problem based on a representative volume element (RVE). A main problem of this approach is the high computational cost, when we have to deal w...
Article
In this contribution we propose a method for the construction of statistically similar representative volume elements (SSRVEs) which are characterized by a much less complexity than usual random RVEs and which represent quite accurately the mechanical response of the real material. For the design of such SSRVEs an objective function is minimized ta...
Chapter
A main problem of direct homogenization methods is the high computational cost, when we have to deal with large random microstructures. This leads to a large number of history variables which needs a large amount of memory, and moreover a high computation time. We focus on random microstructures consisting of a continuous matrix phase with a high n...
Article
Biological soft tissues appearing in arterial walls are characterized by a nearly incompressible, anisotropic, hyperelastic material behavior in the physiological range of deformations. For the representation of such materials we apply a polyconvex strain energy function in order to ensure the existence of minimizers and in order to satisfy the Leg...
Article
In the field of direct homogenization methods large representative volume elements (RVE's) cause a high computational cost, which is indicated by a large number of history variables allocating a large amount of memory. Additionally, a high computation time is necessary to solve the systems of equations on the micro-scale as well as on the macro-sca...
Article
Atherosclerosis has become one of the most frequent causes of death in the last decades. So the analysis and improvement of corresponding medical treatments, e.g., balloon-angioplasty or stenting, are significant tasks in the fields of biomechanics and biomedical engineering. One important component of the simulation of arterial walls, especially o...
Article
The simulation of a balloon–angioplasty (clinical treatment of atherosclerotically degenerated arteries) requires information of the anatomical and physiological composition of the arterial wall. The intravascular ultrasound and the interpretation by a virtual histology provide cross–sectional images of the diseased arterial walls where the differe...
Article
Arterial walls are characterised by nearly incompressible, anisotropic, hyperelastic material behaviour. Several polyconvex material functions representing such materials are considered and adjusted to experimental data. For all of these functions and for different parameter sets numerical simulations using a three-dimensional model of a diseased a...
Article
Biological soft tissues appearing in arterial walls are characterized by a nearly incompressible, anisotropic hyperelastic material behavior in the physiological range of deformations. For the representation of such materials we apply a polyconvex strain energy function in order to ensure the existence of minimizers and in order to satisfy the Lege...
Article
Full-text available
The focus of this contribution is to show the applicability of statistically similar representative volume elements (SSRVEs) for multiscale simulations like the FE 2 -method. Such SSRVEs are characterized by a lower complexity than usual random representative volume elements (RVEs), but they represent quite accurately the mechanical response of the...

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Projects (2)
Project
In formed metallic components, the avoidance or minimization of residual stresses has so far been the main objective, with the aim of improving service life and manufacturability. A goal-oriented use of residual stresses for improvement of properties e.g. the operational strength in the field of forming technology has received rare attention until now. The aim of this project is to analyse the influences on distribution and stability of the residual stress development in thermo-mechanically processed components by means of a targeted process control using both experiments as well as numerical simulations. For this purpose, cylindrical specimen with eccentric holes are thermo-mechanically treated in various process cases in order to investigate the resulting inhomogeneous residual stress states. For the experimental as well as numerical analysis of the evolution and distribution of residual stresses in the used material a comprehensive characterisation of the thermal, metallurgical and mechanical properties was carried out in the first funding period. Due to the classification of residual stresses in 1st, 2nd and 3rd type multiscale numerical models were taken into account. The close interaction between experiment and numerical simulation allowed a calibration and validation of models and material descriptions. With these models a good prediction on the development of residual stresses in the reference process was gained. Furthermore, the developed numerical models are used during the second funding period and enhanced as well as optimized with respect to the new work program. Thereby, a macroscopic, phenomenological description in the framework of the Finite Element Method (FEM) based on thermo-mechanical and metallurgical properties is used for the representation of the residual stresses of the 1st type. For modelling microstructural residual stresses (2nd and 3rd type) and microstructure evolution phasefield models and multiscale FEM simulations are applied. After the validation of material data, the current aim is to investigate the controllability of residual stresses with regard to improve the properties of the hot-formed components. Besides specific control of the forming parameters, spray field cooling for active temperature management will be integrated into the forming process, which makes also further modification of the numerical models necessary. Subsequent numerical and experimental studies are used to analyse the interactions between process parameters and residual stresses. In the long term, a methodology should be developed which allows a deeper understanding of the thermo-mechanical material phenomena in connection with the resulting residual stress evolution occuring during the hot forming. Based on this knowledge, it is aimed for a simulation-aided process design with regard to the goal-oriented adjustment of defined, stable residual stresses, which positively influence the component properties.
Project
Systematic investigations of the deterioration of high- (HPC) and ultra-high-performance concrete (UHPC) subjected to fatigue loading.