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Using finite element (FE) method corrects the microstress field resulting from the theory of homogenization in the region of composite in vicinity of the boundary. Obtains the corrected microstress field via an unsmearing procedure based on the known global solution and local peturbation. Analyses two examples: near a free boundary and next to a constrained border. FE models are constructed using both commercial FE code and the authors’ program for homogenization with some interfacing procedures. Shows qualitative results of computations and estimates influence on the microstress description of the local perturbation near the boundary.

Purpose — The purpose of this paper is to assess the accuracy of homogenization or the smeared stiffness approach in analyzing quadrigrid plates under transverse loads is assessed by comparing two distinct finite element solutions. The grid is assumed to be made of homogeneous isotropic material. However, the numerical solution procedure adopted here is applicable to grids made of unidirectional composite ribs. Design/methodology/approach — The finite element structural analysis is conducted by using plate elements based on the first‐order shear deformable theory (FSDT) and grillage analysis using first‐order shear deformable beam elements. The grillage analysis results, which are taken as the exact results, are compared with the approximate results obtained using FSDT plate elements, where the stiffness matrices obtained by the smeared stiffness approach are incorporated in the plate finite element formulation. Several sample problems are solved and the influences of rib spacing, rib thickness‐to‐width ratio, plate dimensions, and loading are examined. Findings — The results presented here show that homogenization yields reliable results when certain conditions are satisfied. Originality/value — The paper demonstrates that it is necessity to conduct thorough and systematic research studies revealing the accuracy of these models, as the applicability limits of homogenization are not clearly known.

The purpose of this paper is to obtain a permeability law of a gas flow through a permeable medium using particle image velocimetry experimental data as primal information, which is conflated with numerical calculations by means of a multi-scale method.

The D2Q9 single-relaxation-time Lattice Boltzmann model (LBM) implemented in GPU is used for the numerical calculations. In a first homogenized micro-scale, the drag forces are emulated by means of an effective Darcy law acting only in the close neighborhood of the solid structures. A second mesoscopic level of homogenization makes use of the effective drag forces resulting from the first-scale model.

The procedure is applied to an experiment consisting of a regular array of wires. For the first level of homogenization, an effective drag law of the individual elemental obstacles is produced by conflating particle image velocimetry measurements of the flow field around the wires and numerical calculations performed with a GPU implementation of the LBM. In the second homogenization, a Darcy–Forchheimer correlation is produced, which is used in a final homogenized LBM model.

The numerical simulations at the first level of homogenization require a substantial amount of calculations, which in the present case were performed by means of the computational power of a GPU.

The homogenization procedure can be extended to other permeable structures. The micro-scale-level model retrieves the fluid-structure forces between the flow and the obstacles, which are difficult to obtain experimentally either from direct measurement or by indirect assessment from velocity measurements.

Modeling of material behavior by physically or microstructure-based models helps in understanding the relationships between its properties and microstructure. However, the majority of the numerical investigations on the prediction of the deformation behavior of AA2024 alloy are limited to the use of phenomenological or empirical constitutive models, which fail to take into account the actual microscopic-level mechanisms (i.e. crystallographic slip) causing plastic deformation. In order to achieve accurate predictions, the microstructure-based constitutive models involving the underlying physical deformation mechanisms are more reliable. Therefore, the aim of this work is to predict the mechanical response of AA2024-T3 alloy subjected to uniaxial tension at different strain rates, using a dislocation density-based crystal plasticity model in conjunction with computational homogenization.

A dislocation density-based crystal plasticity (CP) model along with computational homogenization is presented here for predicting the mechanical behavior of aluminium alloy AA2024-T3 under uniaxial tension at different strain rates. A representative volume element (RVE) containing 400 grains subjected to periodic boundary conditions has been used for simulations. The effect of mesh discretization on the mechanical response is investigated by considering different meshing resolutions for the RVE. Material parameters of the CP model have been calibrated by fitting the experimental data. Along with the CP model, Johnson–Cook (JC) model is also used for examining the stress-strain behavior of the alloy at various strain rates. Validation of the predictions of CP and JC models is done with the experimental results where the CP model has more accurately captured the deformation behavior of the aluminium alloy.

The CP model is able to predict the mechanical response of AA2024-T3 alloy over a wide range of strain rates with a single set of material parameters. Furthermore, it is observed that the inhomogeneity in stress-strain fields at the grain level is linked to both the orientation of the grains as well as their interactions with one another. The flow and hardening rule parameters influencing the stress-strain curve and capturing the strain rate dependency are also identified.

Computational homogenization-based CP modeling and simulation of deformation behavior of polycrystalline alloy AA2024-T3 alloy at various strain rates is not available in the literature. Therefore, the present computational homogenization-based CP model can be used for predicting the deformation behavior of AA2024-T3 alloy more accurately at both micro and macro scales, under different strain rates.

In some three-dimensional (3D) printing application scenarios, e.g., model manufacture, it is necessary to print large-sized objects. However, it is impossible to implement large-size 3D printing using a single projector in digital light processing (DLP)-based mask projection 3D printing because of the limitations of the digital micromirror device chips.

A multi-projector DLP with energy homogenization (EHMP-DLP) scheme is proposed for large-size 3D printing. First, a large-area printing plane is established by tiling multiple projectors. Second, the projector set’s tiling pattern is obtained automatically, and the maximum printable plane is determined. Third, the energy is homogenized across the entire printable plane by adjusting gray levels of the images input into the projectors. Finally, slices are automatically segmented based on the tiling pattern of the projector set, and the gray levels of these slices are reassigned based on the images of the corresponding projectors.

Large-area high-intensity projection for mask projection 3D printing can be performed by tiling multiple DLP projectors. The tiled projector output energies can be homogenized by adjusting the images of the projectors. Uniform ultraviolet energy is important for high-quality printing.

A prototype device is constructed using two projectors. The printable area becomes 140 × 210 mm from the original 140 × 110 mm.

The proposed EHMP-DLP scheme enables 3D printing of large-size objects with linearly increasing printing times and high printing precision. A device was established using two projectors to practice the scheme and can easily be extended to larger sizes by using more projectors.

The purpose of this paper is to determine the broadband frequency response of the impedance matrix of wireless power transfer (WPT) systems comprising litz wire coils.

A finite-element (FE)-based method is proposed which treats the microstructure of litz wires by an auxiliary cell problem. In the macroscopic model, litz wires are represented by a block with a homogeneous, artificial material whose properties are derived from the cell problem. As the frequency characteristics of the material closely resemble a Debye relaxation, it is possible to convert the macroscopic model to polynomial form, which enables the application of model reduction techniques of moment-matching type.

FE-based model-order reduction using litz wire homogenization provides an efficient approach to the broadband analysis of WPT systems. The error of the reduced-order model (ROM) is comparable to that of the underlying original model and can be controlled by varying the ROM dimension.

Since the present model does not account for displacement currents, the operating frequency of the system must lie well below its first self-resonance frequency.

The proposed method is well-suited for the computer-aided design of WPT systems. It outperforms traditional FE analysis in computational efficiency.

The presented homogenization method employs a new formulation for the cell problem which combines the benefits of several existing approaches. Its incorporation into an order-reduction method enables the fast computation of broadband frequency sweeps.

The purpose of this paper is to present a homogenization approach to model mechanical structures with multiple scales and periodicity, as they occur, e.g. in power transformer windings, subjected to magnetic forces.

The idea is based on the framework of generalized finite element methods (GFEM), where the normal polynomial finite element basis functions are enriched by problem dependent basis functions, which are, in this case, the eigenmodes of a quasi‐periodic unit cell setup. These eigenmodes are used to enrich the standard polynomial basis functions of higher order on a coarse grid modeling the whole periodic structure.

It is shown that heterogeneous magnetomechanical structures can be homogenized with the developed method, as demonstrated by homogenization of a transformer coil setup.

An efficient homogenization procedure is proposed on the basis of the GFEM, which is extended using a special set of enrichment functions, i.e. the mechanic eigenmodes of a generalized eigenvalue problem.

The purpose of this study is to present a multi-scale analysis methodology for calculating the effective stiffnesses and the micro stresses of helically wound structures efficiently and accurately. The helically wound structure is widely applied in ocean and civil engineering as load-bearing structures with high flexibility, such as wire ropes, umbilical cables and flexible risers. Their structures are usually composed of a number of twisted subcomponents with relatively large slender ratio and have the one-dimensional periodic characteristic in the axial direction. As the huge difference between the axial length and the cross-section size of this type of structures, the finite element modeling and theoretical analysis based on some assumption are usually unavailable leading to the reduction of computability; even the optimization design becomes infeasible.

Based on the asymptotic homogenization theory, the one-dimensional periodic helically wound structure is equivalent to the one-dimensional homogeneous beam. A novel implementation of the homogenization is derived for the analysis of the effective mechanical properties of the helically wound structure, and the tensile, bending, torsional and coupling stiffness properties of the effective beam model are obtained. On this basis, a downscaling analysis formation for the micro-component stress in the one-dimensional periodic wound structure is constructed. The stress of micro-components in the specified geometry position of the helically wound structure is obtained basing on the asymptotic homogenization theory simultaneously.

By comparing with the result from finite element established accurately, the established multi-scale calculation method of the one-dimensional periodic helically wound structure is verified. The influence of size effects on the macro effective performance and the micro-component stress is discussed.

This paper will provide the theoretical basis for the efficient elastoplastic analysis of the helically wound structure, even the fatigue analysis. In addition, it is necessary to point out that the axial length of the helically wound structure in the general engineering problems that such as deep-sea risers and submarine cables.

Examines the role of small, locally based management consultancies as global change agents. Based on evidence from Italy, shows that these consultancies not only have managed to develop successful survival strategies, but also play an important role in the dissemination and translation of new management knowledge into a local context, thus contributing to an increasing homogenization of management practice. Draws on new evidence, namely questionnaires completed by Italian consultants as well as a large number of face‐to‐face interviews. It is part of an ongoing, large‐scale research project on management practices in Europe.

The purpose of this paper is to present, the global behaviour of sandwich structures comprising cellular cores is predicted by finite element (FE) analysis. Two modelling approaches are investigated, providing different levels of accuracy; in both approaches, the sandwich structure is idealised as a layered stack with the skin modelled using shell elements; while the core is either modelled with fine detail using beam micro-elements representing the cell struts, or is modelled by three-dimensional solid elements after an appropriate core homogenisation.

The applied homogenisation methodology, as well as the all important modelling issues are presented in detail. Experimental tests performed using a mass-drop testing machine are used for the successful validation of the simulation models.

It was concluded that the core microscale models having detailed FE modelling of the core unit cells geometry with fine scale beam elements are suitable for the analysis of the core failure modes and the prediction of the basic core stiffness and strength properties. It was demonstrated that the homogenised core model provides significant advantages with respect to computing time and cost, although they require additional calculations in order to define the homogenised stress-strain curves.

Special microscale material tests are required for the determination of appropriate materials parameters of the core models, as steel selective laser melting (SLM) microstrut properties differ from the constitutive steel material ones, due to the core manufacturing SLM technique. Stress interactions were not taken into account in the homogenisation, as the applied core material model supports the introduction of independent stress-strain curves; however, the predicted load deflection results appeared to be very close to those obtained from the detailed core micromodels.

The paper is original. The dynamic behaviour of conventional sandwich structures comprising conventional honeycomb type cores has been extensively studied, using simple mass-spring models, energy based models, as well as FE models. However, the response of sandwich panels with innovative SLM cellular cores has been limited. In the present paper, novel modelling approaches for the simulation of the structural response of sandwich panels having innovative open lattice cellular cores produced by SLM are investigated.