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Current research focuses on the induction of residual stresses in a component during its manufacturing process, which shows a significant impact on the final component's properties. During the manufacturing of a hot bulk forming component, the temperature evolution allows to influence the resulting residual stress state efficiently and purposefully. Following the characterization of residual stresses...
The influence of different fiber contents and orientations on the overall material behavior of steel microfiber reinforced UHPC is studied. To analyze the failure behavior of UHPC, the three‐point bending beam tests at low cycle is investigated experimentally and simulated numerically. For that purpose, recently developed phenomenological material model, see our recent works [1] and [2], based on...
The cost‐ and time‐efficient design of today's manufacturing processes is closely linked to numerical simulations. By developing and applying suitable simulation models, component properties can be specifically predicted and, if necessary, modified according to the customer's specifications. One important aspect of this is the adjustment towards advantageous residual stress profiles, for example to...
A phenomenological material model is developed to understand the pseudo‐ductile material behavior of steel fiber reinforced high performance concrete (HPC) during failure. In that respect, an energy function is formulated using an additive composition of a transversal isotropic elasto‐plastic model and an elasto‐plastic phase‐field model representing the individual behavior of the steel fibers and...
The direct current (DC) and alternative current (AC) electromechanically coupled phenomena have been reported in carbon nanotube (CNT)‐based nanocomposite sensors. In this contribution, a unified micromechanics‐based model is established for the DC and AC strain sensors. The electric damage and volume change of nanocomposite are considered to be responsible for the electromechanically coupled effects...
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 parameters and to verify the efficiency of the presented...
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 instance, the targeted adjustment of residual stresses can...
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. The suitable mechanical and periodic boundary conditions...
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 experimental and numerical analyses are an object of current...
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 based on the rank‐one convexification of the pairwise...
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 the Drucker‐Prager plasticity model is used. The numerical...
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 steps for the calculation of residual stresses on microscale...
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 experiments have shown that the bond strength for straight...
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 we extracted the hourly wind peaks over the last two...
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 behavior of a single steel fiber and its influence...
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 macroscopic behavior of DP steels is closely tied...
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 stresses. For this purpose, the thermo‐mechanical behaviour...
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 modeling of the material is the FE 2 - method....
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 on the microscale. Our aim is to directly incorporate...
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 for an efficient computation SSRVEs with a reduced complexity...
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