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Vehicle monitoring is an important prequisite for predictive maintenance applications. Virtual sensors can be deployed to establish relationships between fatigue related quantities of interest and readily available measurement data, which reduces the costs of monitoring for vehicle fleets. This work describes a data‐driven virtual sensing approach using the scattering transform and principal component...
A common strategy for reducing the computational effort of descriptor‐based microstructure reconstruction in the Yeong–Torquato algorithm lies in restricting the choice of descriptors to an efficiently computable subset. As an alternative, the number of iterations can be reduced by gradient‐based optimization as in differentiable microstructure characterization and reconstruction (DMCR). This allows...
Descriptor‐based microstructure characterization plays a crucial role in the field of reversed material engineering for random heterogeneous media. With the advent of differentiable microstructure characterization and reconstruction, there has been a growing interest in the development of differentiable formulations of descriptors. The search for effective descriptors becomes indispensable to adequately...
Labeling time series data according to operating states is often a time‐consuming task that requires expert domain knowledge of the underlying mechanical system. In this paper, we propose a data‐driven algorithm that identifies and detects operating states from time series data by grouping time ranges of similar signal behavior together using an unsupervised machine learning approach. The scattering...
In machining technologies for fibre reinforced polymers, remote laser cutting plays a special role as it can minimize the drawbacks of conventional laser cutting methods, in particular thermally induced damage such as charred edges and matrix evaporation. In this contribution, a thermal simulation model for the remote laser cutting process is presented. With the aim of a universally applicable model...
In this contribution, the causes leading to the undesired unevenness on the exterior surface of a paper‐based sandwich structure during the manufacturing process are investigated. This provides insight into the manufacturing parameters that need to be adjusted to reduce this waviness. A finite element model of the pressing process is developed in the commercial software ABAQUS and then used to analyze...
Laser shock peening (LSP) is a promising technique to systematically introduce local compressive residual stresses in metal sheets, inhibiting fatigue cracks in these areas. We model fatigue crack growth in these specimen with the help of a phase‐field model for fatigue fracture [1]. First, we parametrise the model using untreated aluminium specimens. In a second step, we use the determined parameters...
Lattice structures and their characterization are much discussed in current research. The complex manufacturing process of laser powder bed fusion with its repeated melting and remelting of metallic powder influences the resulting material properties.
Within this contribution the influence of process parameters on the overall behaviour of lattice structure compression test specimens is inherently...
Herein, a neural network‐based constitutive model for isotropic hyperelastic solids which makes use of a physically motivated dimensionality reduction into the invariant space is presented. In order to automatically fulfill thermodynamic consistency, gradients of the network with respect to the input quantities are considered within a customized training loop. The proposed approach is exemplarily...
In this contribution, we introduce a hybrid model for virtual sensing applications which combines a frequency response function model with a Long Short‐Term Memory network. It estimates the behavior of non‐linear dynamic systems with multiple input and output channels by generating predictions on short subsequences of signals and recombining them using a windowing technique. The approach is tested...
Herein, a unified phase‐field formulation of fracture in viscoelastic materials is presented. The model is characterised by a pseudo‐energy functional from which the governing equations for the phase‐field and the viscous internal variables are derived. Depending on the specific choice of the parameters, the formulation has flexibility in capturing the coupling between viscous mechanisms and fracture...
In this contribution a modelling approach for the laser cutting process simulation of carbon fibre reinforced polymers is introduced. The cutting process is modelled in a 3D thermal simulation, the material is modelled layer‐wise orthotropically. For the evaporation of matrix and fibre phase transitions are utilised. The laser spot is modelled with its gaussian distribution as a heat input on the...
In this contribution, a variational crack phase‐field model for heterogeneous materials is used to study periodic microstructures. The discontinuity at material interfaces is taken into account by an additional static order parameter. A partial rank‐I relaxation ensures the pointwise fulfillment of the Hadamard jump condition and static equilibrium within the diffuse interface. Crack propagation is...
In engineering practice generally empirical durability concepts, such as the Local Strain Approach (LSA) [1], are used for the fatigue life estimation of components. The LSA calculation is based on a given series of reversal points of the elastic stress history, e.g. computed in terms of a finite element model of the component. The fatigue life of components is subject to various factors. During the...
Recently, the problem of modelling fatigue fracture has been approached by the phase‐field method. The approach of Seiler et al. [1] focusses on a reduction of computational cost by combing the phase‐field method for fracture with a classic fatigue concept. For this model, we perform a parameter study analysing the influence of the fatigue degradation function and the crack propagation behaviour under...
In this contribution, particle‐matrix interactions in magneto‐active elastomers are analyzed with regard to the resulting mechanical deformations. By comparing experimental observations with the results of finite element simulations, a fully coupled continuum model for magneto‐active elastomers is validated with the help of real data. The model under consideration permits the investigation of magneto‐active...
In this contribution, the interface region of a fiber reinforced polymer and a metal component is considered within a representative volume element. The connecting surface exhibits a random height distribution with a defined roughness. Under shear loading, different failure mechanisms are studied with respect to the local interface roughness. Furthermore, adhesive failure of the interface and cohesive...
In this contribution, we apply adaptive isogeometric analysis to a phase‐field model for topology optimization. To increase the efficiency of the computation, we perform local mesh refinement and coarsening between the time increments of the simulation. To provide a trial solution for the iterative solver of the next increment, state variables are projected from the old to the new mesh. The quality...
When it comes to failure of a heterogeneous material, the adhesive interfaces linking the different constituents can crucially influence its mechanical behavior. In this contribution, a diffuse description of interfaces in the context of the phase‐field approach to brittle fracture is outlined. Two‐ and three‐dimensional simulations of crack phenomena are presented and serve for validation of the...
Herein, the development and calibration of a macroscopic model for magneto‐active elastomers based on data generated from computational homogenizations is presented. The advantage of this strategy is the possibility to adjust the model independent of any macroscopic sample geometry. Using the calibrated model, the magnetostrictive and magnetorheological effect of macroscopic samples are simulated...
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