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van den Boom, S.J. (author), van Keulen, A. (author), Aragon, A.M. (author)An immersed enriched finite element method is proposed for the analysis of phononic crystals (PnCs) with finite element (FE) meshes that are completely decoupled from geometry. Particularly, a technique is proposed to prescribe Bloch–Floquet periodic boundary conditions strongly on non-matching edges of the periodic unit cell (PUC). The...journal article 2021
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van de Ven, E.A. (author), Maas, Robert (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)Although additive manufacturing (AM) allows for a large design freedom, there are some manufacturing limitations that have to be taken into consideration. One of the most restricting design rules is the minimum allowable overhang angle. To make topology optimization suitable for AM, several algorithms have been published to enforce a minimum...journal article 2021
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Bijster, R.J.F. (author), van Keulen, A. (author)Multilayer cantilever beams are used in the measurement of near-field radiative heat transfer. The materials and dimensions of the cantilever probe are chosen in order to improve system performance in terms of sensitivity and noise. This is done using an analytical model that describes the thermo-mechanical and mechanical behavior of the...journal article 2021
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Zhang, Y. (author), Tichem, M. (author), van Keulen, A. (author)Multi-stable metastructures composed of curved beams can switch to a series of stable configurations via elastic snap-through transitions. The elastic deformations allow metastructures to function as reusable energy absorbers. However, conventional metastructure designs based on solid beams often result in relatively low energy dissipation....journal article 2021
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Misiun, Grzegorz (author), van de Ven, E.A. (author), Langelaar, Matthijs (author), Geijselaers, Hubert (author), van Keulen, A. (author), van den Boogaard, Ton (author), Ayas, C. (author)An important cause of failure in powder bed additive manufacturing is the distortion of the part due to thermal shrinkage during printing and the relaxation of residual stresses after its release from the base plate. In this paper, Additive Manufacturing simulations are coupled with Topology Optimization in order to generate designs that are...journal article 2021
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De Lazzari, Elena (author), van den Boom, S.J. (author), Zhang, J. (author), van Keulen, A. (author), Aragon, A.M. (author)Enriched finite element methods have gained traction in recent years for modeling problems with material interfaces and cracks. By means of enrichment functions that incorporate a priori behavior about the solution, these methods decouple the finite element (FE) discretization from the geometric configuration of such discontinuities. Taking...journal article 2021
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Zhang, Y. (author), Tichem, M. (author), van Keulen, A. (author)Metastructures consisting of planar arrangements of bi-stable snap-through beams are able to exhibit multiple stable configurations. Apart from the expected translational state transition, when all beam elements snap through, rotational states may exist as well. In this paper we explore the rotational properties of multi-stable metastructures...journal article 2021
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van de Ven, E.A. (author), Ayas, C. (author), Langelaar, Matthijs (author), Maas, Robert (author), van Keulen, A. (author)Additive manufacturing (AM) and topology optimization (TO) have a synergetic relation, as AM can produce complex TO designs, and TO provides high-performance parts that utilize the form freedom provided by AM. Recently, TO has been tailored more toward AM with the inclusion of the minimum allowable overhang angle as a design constraint:...journal article 2021
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van den Boom, S.J. (author), Zhang, J. (author), van Keulen, A. (author), Aragon, A.M. (author)During design optimization, a smooth description of the geometry is important, especially for problems that are sensitive to the way interfaces are resolved, e.g., wave propagation or fluid-structure interaction. A level set description of the boundary, when combined with an enriched finite element formulation, offers a smoother description...journal article 2020
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Yang, Y. (author), van Keulen, A. (author), Ayas, C. (author)Selective laser melting (SLM) is a widely used additive manufacturing method for building metal parts in a layer-by-layer manner thereby imposing almost no limitations on the geometrical layout of the part. The SLM process has a crucial impact on the microstructure, strength, surface quality and even the shape of the part, all of which depend on...journal article 2020
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van de Ven, E.A. (author), Maas, Robert (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)It is attractive to combine topology optimization (TO) with additive manufacturing (AM), due to the design freedom provided by AM, and the increased performance that can be achieved with TO. One important aspect is to include the design rules associated with the process restrictions of AM to prevent the requirement of relatively large support...journal article 2020
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Delissen, A.A.T.M. (author), van Keulen, A. (author), Langelaar, Matthijs (author)In many engineering applications, the dynamic frequency response of systems is of high importance. In this paper, we focus on limiting the extreme values in frequency response functions, which occur at the eigenfrequencies of the system, better known as resonant peaks. Within an optimization, merely sampling the frequency range and limiting the...journal article 2020
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Zhang, Y. (author), Wang, Q. (author), Tichem, M. (author), van Keulen, A. (author)Multi-stable structures are able to achieve significant geometric change and retain specific deformed configurations after the loads have been removed. This reconfiguration property enables, for example, to design metamaterials with tunable features. In this work, a type of multi-stable metastructures exhibiting both level and tilted stable...journal article 2020
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Ranjan, R. (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author)The powder bed fusion (PBF) process is a type of Additive Manufacturing (AM) technique which enables fabrication of highly complex geometries with unprecedented design freedom. However, PBF still suffers from manufacturing constraints which, if overlooked, can cause various types of defects in the final part. One such constraint is the local...journal article 2020
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Delissen, A.A.T.M. (author), Laro, Dick (author), Kleijnen, Harry (author), van Keulen, A. (author), Langelaar, Matthijs (author)In the design process of high-precision motion stages, the dynamic behavior is of paramount importance. Manual design of such a stage is a time-consuming process, involving many iterations between engineers responsible for mechanics, dynamics and control. By using topology optimization in combination with additive manufacturing, post...conference paper 2020
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Gupta, D.K. (author), van Keulen, A. (author), Langelaar, Matthijs (author)Multiresolution topology optimization (MTO) methods involve decoupling of the design and analysis discretizations, such that a high‐resolution design can be obtained at relatively low analysis costs. Recent studies have shown that the MTO method can be approximately 3 and 30 times faster than the traditional topology optimization method for 2D...journal article 2020
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Sinico, Mirko (author), Ranjan, R. (author), Moshiri, Mandana (author), Ayas, C. (author), Langelaar, Matthijs (author), van Keulen, A. (author), Dewulf, Wim (author), Witvrouw, Ann (author)Numerous challenges of additive manufacturing (AM) are tackled in the European Horizon 2020 project PAM^2 by studying and linking every step of the AM process cycle. For example, PAM^2 researchers from the design, processing and application side have collaborated in this work to optimise the manufacturability of metal AM parts using an improved...journal article 2019
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Zhang, J. (author), van den Boom, S.J. (author), van Keulen, A. (author), Aragon, A.M. (author)A new enriched finite element technique, named the Discontinuity-Enriched Finite Element Method (DE-FEM), was introduced recently for solving problems with both weak and strong discontinuities in 2-D. In this mesh-independent procedure, enriched degrees of freedom are added to new nodes collocated at the intersections between discontinuities...journal article 2019
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Wang, W. (author), Munro, D.P. (author), Wang, C.C. (author), van Keulen, A. (author), Wu, J. (author)The design of optimal structures and the planning of (additive manufacturing) fabrication sequences have been considered typically as two separate tasks that are performed consecutively. In the light of recent advances in robot-assisted (wire-arc) additive manufacturing which enable addition of material along curved surfaces, we present a...journal article 2019
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Wu, L. (author), Tiso, P. (author), Tatsis, Konstantinos (author), Chatzi, Eleni (author), van Keulen, A. (author)This paper presents a novel model order reduction technique for 3D flexible multibody systems featuring nonlinear elastic behavior. We adopt the mean-axis floating frame approach in combination with an enhanced Rubin substructuring technique for the construction of the reduction basis. The standard Rubin reduction basis is augmented with the...journal article 2019